WO2008098676A1

WO2008098676A1 - Process for producing sec-butylbenzene

Info

Publication number: WO2008098676A1
Application number: PCT/EP2008/000664
Authority: WO
Inventors: Jane C. Cheng; Michael C. Clark; Terry E. Helton; Michael J. Brennan; Gordon J. Kennedy; Mohan Kalyanaraman
Original assignee: Exxonmobil Chemical Patents Inc.; Exxonmobil Chemical Limited
Priority date: 2007-02-13
Filing date: 2008-01-25
Publication date: 2008-08-21
Also published as: TW200904778A

Abstract

A process for producing sec-butylbenzene comprises reacting benzene with at least one linear butene under alkylation conditions and in the presence of a catalyst comprising at least one molecular sieve having an X-ray diffraction pattern including d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstrom to produce an alkylation product comprising sec- butylbenzene. Prior to the reacting, the catalyst is contacted with water under conditions to improve the sec-butylbenzene selectivity of the catalyst.

Description

PROCESS FOR PRODUCING SEC-BUTYLBENZENE

FIELD

[0001] The present invention relates to a process for producing sec-butylbenzene and for converting the sec-butylbenzene to phenol and methyl ethyl ketone.

BACKGROUND

[0002] Phenol and methyl ethyl ketone are important products in the chemical industry. For example, phenol is useful in the production of phenolic resins, bisphenol A, ε-caprolactam, adipic acid, alkyl phenols, and plasticizers, whereas methyl ethyl ketone can be used as a lacquer, a solvent and for dewaxing of lubricating oils.

[0003] The most common route for the production of methyl ethyl ketone is by dehydrogenation of sec-butyl alcohol (SBA), with the alcohol being produced by the acid-catalyzed hydration of butenes. For example, commercial scale SBA manufacture by reaction of butylene with sulfuric acid has been accomplished for many years via gas/liquid extraction.

[0004] Currently, the most common route for the production of phenol is the Hock process. This is a three-step process in which the first step involves alkylation of benzene with propylene to produce cumene, followed by oxidation of the cumene to the corresponding hydroperoxide and then cleavage of the hydroperoxide to produce equimolar amounts of phenol and acetone. However, the world demand for phenol is growing more rapidly than that for acetone. In addition, the cost of propylene relative to that for butenes is likely to increase, due to a developing shortage of propylene. Thus, a process that uses butenes instead of propylene as feed and coproduces methyl ethyl ketone rather than acetone may be an attractive alternative route to the production of phenol. [0005] It is known that phenol and methyl ethyl ketone can be co-produced by a variation of the Hock process in which sec-butylbenzene is oxidized to obtain sec- butylbenzene hydroperoxide and the peroxide decomposed to the desired phenol and methyl ethyl ketone. An overview of such a process is described in pages 1 13-421 and 261 -263 of Process Economics Report No. 22B entitled "Phenol", published by the Stanford Research Institute in December 1977. [0006] Sec-butylbenzene can be produced by alkylating benzene with n-butenes over an acid catalyst. Thus, in our International Patent Publication No. WO 06/15826 we have described an integrated process for producing phenol and methyl ethyl ketone, in which a feed comprising benzene and a C₄ alkylating agent is contacted under alkylation conditions with a catalyst comprising zeolite beta or an MCM-22 family molecular sieve to produce an alkylation effluent comprising sec-butylbenzene. The sec-butylbenzene is then oxidized to produce a hydroperoxide and the hydroperoxide is cleaved to produce the desired phenol and methyl ethyl ketone.

[0007] Traditionally, molecular sieves such as zeolite beta and the MCM-22 family materials are produced by reacting an aqueous mixture of a source of silica or other tetravalent metal oxide, a source of alumina or other trivalent metal oxide and a directing agent, generally a nitrogen-containing organic base, at elevated temperatures for several hours to a few days until a crystalline product is obtained. The crystalline product is then separated from the remainder of the synthesis mixture and subjected to a variety of finishing steps, such as extrusion, ion exchange and calcination before being used as a catalyst for example in the alkylation process described in WO 06/15826. Generally, the final step in the catalyst preparation is a calcination step or at least a drying step at 130°C to 220°C in the presence of an inert gas, such as nitrogen, to remove water adsorbed during storage. Thus, molecular sieve catalysts are typically very dry when used as catalysts in processes such as the production of sec-butylbenzene. [0008] When molecular sieve catalysts, such as zeolite beta and the MCM-22 family materials, are used in the production of sec-butylbenzene, there is usually a lineout period, immediately following start-up, during which the catalyst produces high levels of dialkylation and trialkylation products. Depending on how the catalyst is produced and calcined, sec-butylbenzene selectivity during startup and at steady-state production can vary considerably. Although polyalkylated products can be converted back to sec-butylbenzene by transalkylation, this adds an additional step and hence there is significant interest in optimizing monoalkylation selectivity both during start-up and at steady state conditions. [0009] According to the present invention, it has now been found that the sec- butylbenzene selectivity of MCM-22 family materials can be enhanced, both during start-up and at steady state conditions, by contacting the molecular sieve with water in vapor or liquid form prior to use of the molecular sieve in the alkylation process to produce the sec-butylbenzene. Although the reason for the improved selectivity is not fully understood, 29Si MAS NMR data suggest that the water contacting promotes re-insertion of Al into the tetrahedral framework of the zeolite and/or a relaxation of the local geometric strains that are induced by earlier steps in the zeolite production, particularly calcination and/or dehydration. Irrespective of the reason for the improved selectivity, it is found that the improvement is maintained even if the zeolite is dried at around 150⁰C after the water contacting step and before being used in the alkylation process. [0010] US Patent No. 4,468,475 discloses a hydrothermal method for enhancing the acid catalytic activity of a high-silica crystalline zeolite, such as ZSM-5, which comprises mixing the zeolite with an activating amount of alumina; and then contacting the mixture of zeolite and alumina with an aqueous liquid medium, typically water, at elevated temperature of about 100°C to 370°C under conditions to increase catalytic activity of the zeolite.

[0011] US Patent No. 5,077,445 discloses a process for preparing an alkylbenzene, particularly ethylbenzene, wherein the process comprises contacting an olefin having from 2 to 6 carbon atoms and liquid benzene with a catalyst under alkylation conditions, said catalyst comprising a hydrated synthetic porous crystalline MCM-22 material, said hydrated crystalline material comprising at least 10% by weight of liquid water included in the pore space of the crystalline material when the crystalline material is first contacted with said benzene and olefin, wherein the alkylation conditions include a combination of temperature and pressure sufficient to maintain said benzene and said water in the liquid state, wherein said hydrated crystalline material is hydrated by placing the crystalline material in liquid water for a time sufficient to sorb at least 10% by weight of water in the pore space of the crystalline material. The presence of water is said to inhibit multi-alkylation reactions, thus minimizing the formation of undesirable by-products, especially those having 9 or more carbon atoms.

SUMMARY [0012] In one aspect, the present invention resides in a process for producing sec- butylbenzene, the process comprising reacting benzene with at least one C4 alkylating agent under alkylation conditions and in the presence of a catalyst comprising at least one molecular sieve of the MCM-22 family to produce an alkylation product comprising sec-butylbenzene, wherein, prior to said reacting, said catalyst is contacted with water under conditions to improve the sec- butylbenzene selectivity of the catalyst.

[0013] In another aspect, the present invention resides in the use of a catalyst comprising at least one molecular sieve of the MCM-22 family in a process for producing sec-butylbenzene by reacting benzene with a C4 alkylating agent under alkylating conditions, which molecular sieve has been contacted with water prior to said use, to improve the sec-butylbenzene selectivity of said catalyst. [0014] In a preferred embodiment the sec-butylbenzene selectivity of the catalyst that has been contacted with water, as required by the process of the invention, is at least 1 wt %, more preferably at least 2 wt %, and even at least 3 wt % higher than the sec-butylbenzene selectivity obtained with otherwise identical reactants, catalyst and process conditions but where the catalyst has not been contacted with water.

[0015] Conveniently, said contacting with water is conducted under conditions including at a temperature of at least 0°C. The water contacting is preferably carried out for a time of at least 0.5 hour. The more preferred water contacting temperature is in the range of about 10°C to about 50°C and the more preferred water contacting time is in the range of about 2 hours to about 24 hours. [0016] In one embodiment, said contacting with water is conducted under conditions sufficient to produce changes in the amplitude or width of at least one peak in the 29Si MAS NMR spectrum of the catalyst in the chemical shift range of -80 to -120 ppm from tetramethylsilane (TMS), more particularly in the range of -90 to -100, -94 to -100 or around -98 ppm from TMS. [0017] In one embodiment, said catalyst is contacted with liquid water. In a further embodiment, said catalyst is contacted with water vapor.

[0018] Conveniently, said catalyst is dried after being contacted with water and prior to said reacting. The drying temperature may be, for example, in the range of about 100°C to about 200°C. Preferably the drying is carried out for a time of about 1 hour to about 5 hours.

[0019] Conveniently, said C4 alkylating agent comprises a linear butene, such as butene- 1 , butene-2 or a mixture thereof. Preferably, said linear butene is added to the process in stages such that said alkylation conditions include an overall molar ratio of benzene to butene from about 1 to about 20, preferably about 3 to aboutl O, more preferably about 4 to about 9.

[0020] Conveniently, said alkylation conditions also include a temperature of from about 60°C to about 260°C and/or a pressure of 7000 kPa or less and/or a feed weight hourly space velocity (WHSV) based on C₄ alkylating agent of from about 0.1 to 50 hr^"1.

[0021 ] In one embodiment, said reacting is conducted under at least partial liquid phase conditions.

[0022] Typically, the molecular sieve of the MCM-22 family has an X-ray diffraction pattern including d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstrom. Conveniently, the molecular sieve is selected from

MCM-22, PSH-3, SSZ-25, ERB-I , ITQ-I, ITQ-2, MCM-36, MCM-49, MCM-56,

UZM-8, and mixtures thereof.

[0023] In one embodiment the process of the invention further comprises oxidizing the sec-butylbenzene to produce a hydroperoxide and cleaving the hydroperoxide to produce phenol and methyl ethyl ketone. Accordingly, in a further, preferred, aspect, the present invention resides in a process for producing phenol and methyl ethyl ketone, the process comprising:

(a) contacting a catalyst comprising at least one molecular sieve of the

MCM-22 family with water; (b) after (a), reacting benzene with at least one linear butene under alkylation conditions and in the presence of said catalyst to produce an alkylation effluent comprising sec-butylbenzene; (c) oxidizing the sec-butylbenzene from (b) to produce a hydroperoxide; and

(d) cleaving the hydroperoxide from (c) to produce phenol and methyl ethyl ketone. [0024] Conveniently, the oxidizing [step (c) in the preferred aspect detailed above] is conducted in the presence of a catalyst, such as a catalyst selected from (i) an oxo (hydroxo) bridged tetranuclear metal complex comprising manganese, (ii) an oxo (hydroxo) bridged tetranuclear metal complex having a mixed metal core, one metal of the core being a divalent metal selected from Zn, Cu, Fe, Co, Ni, Mn and mixtures thereof and another metal being a trivalent metal selected from In, Fe, Mn, Ga, Al and mixtures thereof, (iii) an N-hydroxy substituted cyclic imide either alone or in the presence of a free radical initiator, and (iv) N,N',N"-trihydroxyisocyanuric acid either alone or in the presence of a free radical initiator. In one embodiment, the oxidization catalyst is a heterogeneous catalyst. [0025] Conveniently, the oxidizing is conducted at a temperature of about 70°C to about 200°C and/or a pressure of about 50 to about 2000 kPa (0.5 to 20 atmospheres).

[0026] Conveniently, the cleaving [step (d) in the preferred aspect detailed above] is conducted in the presence of a catalyst. The catalyst can be a homogeneous or heterogeneous catalyst. In one embodiment, the catalyst is a homogeneous catalyst, such as sulfuric acid.

[0027] Conveniently, the cleaving is conducted at a temperature of about 40°C to about 120⁰C and/or a pressure of about 100 to about 2500 kPa and/or a liquid hourly space velocity (LHSV) based on the hydroperoxide of about 0.1 to about 100 hr^'1.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a graph of sec-butylbenzene selectivity against time on stream for the dried MCM-49/V300 catalyst of Example 1 and the humidified MCM- 49/V300 catalyst of Example 2. It shows that humidification improves SBB selectivity. [0029] Figure 2 is a graph of weight % of dibutylbenzene to sec-butylbenzene against time on stream for the dried MCM-49/V300 catalyst of Example 1 and the humidified MCM-49/V300 catalyst of Example 2. It shows that humidification reduces dialkylation. [0030] Figures 3 (a) and (b) are graphs comparing the sec-butylbenzene selectivity and the weight % of dibutylbenzene to sec-butylbenzene against time on stream for the MCM-49/V300 catalysts of Examples 1 to 3. [0031] Figures 4 (a) and (b) are graphs comparing the sec-butylbenzene selectivity and the weight % of dibutylbenzene to sec-butylbenzene against time on stream for the MCM-49/V300 catalysts of Examples 1 to 4.

[0032] Figures 5 (a) and (b) are graphs comparing the sec-butylbenzene selectivity and the weight % of dibutylbenzene to sec-butylbenzene against time on stream for the MCM-49/V300 catalysts of Examples 1 to 5. Figures 3(a), 4(a) and 5(a) show that humidification improves SBB selectivity; and Figures 3(b), 4(b) and 5(b) show that humidification reduces dialkylation.

[0033] Figures 6 (a) and (b) are graphs comparing the sec-butylbenzene selectivity and the weight % of dibutylbenzene to sec-butylbenzene against time on stream for the MCM-49/Condea catalysts of Examples 6 and 7. Figure 6(a) shows that humidification results in a better SBB selectivity than is obtained with dry catalyst, both at start up and after several days on stream. Figure 6(b) shows that humidification results in lower dialkylation than is obtained with dry catalyst both at start up and after several days on stream.

[0034] Figure 7 compares the ²⁹Si MAS NMR spectra in the chemical shift range of -70 to -140 ppm for the dried MCM-49/V300 catalyst of Example 1 and the humidified MCM-49/V300 catalyst of Example 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The present invention is directed to a process for producing sec- butylbenzene by alkylating benzene with a C₄ alkylating agent in the presence of a catalyst comprising a zeolite of the MCM-22 family, wherein the zeolite has undergone prior treatment with water. In particular, the invention is based on the discovery that water treatment of MCM-22 family zeolites enhances their sec- butylbenzene selectivity both during start-up and at steady state conditions. Surprisingly, this improvement, which is not exhibited by other zeolites known to be active alkylation catalysts, such as zeolite beta, is retained even if the water- treated zeolite undergoes a subsequent drying step. (0036] In addition to improved sec-butylbenzene selectivity, the water treatment is found to decrease the amount of butene oligomers and polybutylbenzenes produced as by-products to the alkylation step. This reduction in oligomer formation, which is not a problem with lower alkene feeds, such as ethylene, is particularly important when the sec-butylbenzene is to be used in the production of phenol and methyl ethyl ketone, in which the sec-butylbenzene is initially oxidized to the corresponding hydroperoxide and the resulting hydroperoxide is then cleaved to produce the desired phenol and methyl ethyl ketone (MEK). Thus the oxidation of sec-butylbenzene is highly sensitive to the presence of impurities, particularly butene oligomers, and hence any alkylation process that increase^'s sec- butylbenzene production and decreases butene oligomer production provides significant advantages in the overall phenol/MEK production regime.

Benzene Alkylation

[0037] The benzene employed in the alkylation step to produce sec-butylbenzene can be any commercially available benzene feed, but preferably the benzene has a purity level of at least 99 wt%.

[0038] The C₄ alkylating agent comprises at least one linear butene, namely butene- 1 , butene-2 or a mixture thereof. The alkylating agent can also be an olefinic C₄ hydrocarbon mixture containing linear butenes, such as can be obtained by steam cracking of ethane, propane, butane, LPG and light naphthas, catalytic cracking of naphthas and other refinery feedstocks and by conversion of oxygenates, such as methanol, to lower olefins.

[0039] For example, the following C₄ hydrocarbon mixtures are generally available in any refinery employing steam cracking to produce olefins; a crude steam cracked butene stream, Raffinate-1 (the product remaining after solvent extraction or hydrogenation to remove butadiene from the crude steam cracked butene stream) and Raffinate-2 (the product remaining after removal of butadiene and isobutene from the crude steam cracked butene stream). Generally, these streams have compositions within the weight ranges indicated in Table 1 below.

Table 1

[0040] Other refinery mixed C₄ streams, such as those obtained by catalytic cracking of naphthas and other refinery feedstocks, typically have the following composition:

Propylene = 0-2 wt% Propane = 0-2 wt% Butadiene = 0-5 wt%

Butene- 1 = 5-20 wt% Butene-2 = 10-50 wt% Isobutene = 5-25 wt% Iso-butane = 10-45 wt% N-butane = 5-25 wt% [0041] C₄ hydrocarbon fractions obtained from the conversion of oxygenates, such as methanol, to lower olefins more typically have the following composition: Propylene = 0-1 wt%

Propane = 0-0.5 wt% Butadiene = 0-l wt%

Butene-1 = 10-40 wt%

Butene-2 = 50-85 wt%

Isobutene = 0-10 wt%

N- + iso-butane = 0-10 wt% [0042] Any one or any mixture of the above C₄ hydrocarbon mixtures can be used in the present alkylation process. In addition to linear butenes and butanes, these mixtures typically contain components, such as isobutene and butadiene, which can be deleterious to the alkylation process. For example, the normal alkylation product of isobutene with benzene is tert-butylbenzene which, as previously stated, acts as an inhibitor to the subsequent oxidation step. Thus, prior to the alkylation step, these mixtures preferably are subjected to butadiene removal and isobutene removal. For example, isobutene can be removed by selective dimerization or reaction with methanol to produce MTBE, whereas butadiene can be removed by extraction or selective hydrogenation to butene-1. Preferably, the C₄ alkylating agent employed in the present process contains less than 1 wt% isobutene and less than 0.1 wt% butadiene.

[0043] In addition to other hydrocarbon components, commercial C₄ hydrocarbon mixtures typically contain other impurities which could be detrimental to the alkylation process. For example, refinery C₄ hydrocarbon streams typically contain nitrogen and sulfur impurities, whereas C₄ hydrocarbon streams obtained by oxygenate conversion process typically contain unreacted oxygenates and water. Thus, prior to the alkylation step, these mixtures may also be subjected to one or more of sulfur removal, nitrogen removal and oxygenate removal, in addition to butadiene removal and isobutene removal. Removal of sulfur, nitrogen, oxygenate impurities is conveniently effected by one or a combination of caustic treatment, water washing, distillation, adsorption using molecular sieves and/or membrane separation. Water is also typically removed by adsorption. [0044] Conveniently, the total feed to the alkylation step of the present process contains less than 1000 ppm, such as less than 500 ppm, for example less than 100 ppm, water; and/or, the total feed typically contains less than 100 ppm, such as less than 30 ppm, for example less than 3 ppm, sulfur; and/or the total feed typically contains less than 10 ppm, such as less than 1 ppm, for example less than 0.1 ppm, nitrogen.

[0045] Although not preferred, it is also possible to employ a mixture of a C₄ alkylating agent, as described above, and C₃ alkylating agent, such as propylene, as the alkylating agent in the present alkylation process so that the alkylation step produces a mixture of cumene and sec-butylbenzene. The resultant mixture can then be processed through oxidation and cleavage, to make a mixture of acetone and MEK, along with phenol, preferably where the molar ratio of acetone to phenol is 0.5: 1, to match the demand for bisphenol-A production.

[0046] The alkylation catalyst used in the present process is a crystalline molecular sieve of the MCM-22 family. The term "MCM-22 family material" (or

"material of the MCM-22 family" or "molecular sieve of the MCM-22 family" or

"MCM-22 family zeolite"), as used herein, includes one or more of: • molecular sieves made from a common first degree crystalline building block unit cell, which unit cell has the MWW framework topology. (A unit cell is a spatial arrangement of atoms which if tiled in three-dimensional space describes the crystal structure. Such crystal structures are discussed in the "Atlas of Zeolite Framework Types", Fifth edition, 2001, the entire content of which is incorporated as reference);

• molecular sieves made from a common second degree building block, being a 2-dimensional tiling of such MWW framework topology unit cells, forming a monolayer of one unit cell thickness, preferably one c-unit cell thickness; • molecular sieves made from common second degree building blocks, being layers of one or more than one unit cell thickness, wherein the layer of more than one unit cell thickness is made from stacking, packing, or binding at least two monolayers of one unit cell thickness. The stacking of such second degree building blocks can be in a regular fashion, an irregular fashion, a random fashion, or any combination thereof; and

• molecular sieves made by any regular or random 2-dimensional or 3- dimensional combination of unit cells having the MWW framework topology.

[0047] Molecular sieves of the MCM-22 family include those molecular sieves having an X-ray diffraction pattern including d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstrom. The X-ray diffraction data used to characterize the material are obtained by standard techniques using the K-alpha doublet of copper as incident radiation and a diffractometer equipped with a scintillation counter and associated computer as the collection system. [0048] Materials of the MCM-22 family include MCM-22 (described in U.S. Patent No. 4,954,325), PSH-3 (described in U.S. Patent No. 4,439,409), SSZ-25 (described in U.S. Patent No. 4,826,667), ERB-I (described in European Patent No. 0293032), ITQ-I (described in U.S. Patent No 6,077,498), ITQ-2 (described in International Patent Publication No. WO97/17290), MCM-36 (described in U.S. Patent No. 5,250,277), MCM-49 (described in U.S. Patent No. 5,236,575), MCM- 56 (described in U.S. Patent No. 5,362,697), UZM-8 (described in U.S. Patent No. 6,756,030), and mixtures thereof. Molecular sieves of the MCM-22 family are preferred as the alkylation catalyst since they have been found to be highly selective to the production of sec-butylbenzene, as compared with the other butylbenzene isomers. Preferably, the molecular sieve is selected from (a) MCM- 49, (b) MCM-56 and (c) isotypes of MCM-49 and MCM-56, such as ITQ-2. [0049] The alkylation catalyst can include the molecular sieve in unbound or self- bound form or, alternatively, the molecular sieve can be combined in a conventional manner with an oxide binder, such as alumina, such that the final alkylation catalyst preferably contains between 2 and 80 wt% sieve. [0050] In one embodiment, the catalyst is unbound and has a crush strength much superior to that of catalysts formulated with binders. Such a catalyst is conveniently prepared by a vapor phase crystallization process, in particular a vapor phase crystallization process that prevents caustic used in the synthesis mixture from remaining in the zeolite crystals as vapor phase crystallization occurs.

[0051 J Prior to use in the present alkylation process, the MCM-22 family zeolite, either in bound or unbound form, is contacted with water, either in liquid or vapor form, under conditions to improve its sec-butylbenzene selectivity. Although the conditions of the water contacting are not closely controlled, improvement in sec- butylbenzene selectivity can generally be achieved by contacting the zeolite with water at temperature of at least 0°C, such as from about 10°C to about 50°C. Preferably the contacting is carried out for a time of at least 0.5 hour, for example for a time of about 2 hours to about 24 hours. Typically, the water contacting is conducted so as to increase the weight of the catalyst by from 20 to 80 wt%, preferably 25 to 80 wt%, more preferably 30 to 75 wt%, for example 40 to 60 wt% based on the initial weight of the zeolite. [0052] Although the reason for the improved selectivity is not fully understood, it is believed that the water contacting promotes re-insertion of the trivalent metal, usually aluminium, into the tetrahedral framework of the zeolite and/or a relaxation of the local geometric strains that are induced by earlier steps in the zeolite production, particularly calcination and/or dehydration. As a result, the water contacting seems to be accompanied by increases in the amplitude or width of at least one of the peaks in the ²⁹Si MAS NMR spectrum of the zeolite in the chemical shift range of -80 to -120 ppm from tetramethylsilane (TMS). In particular, the water contacting frequently seems to improve the resolution of a peak in the -90 to -100 ppm chemical shift range Of ²⁹Si MAS NMR spectrum of the zeolite, which peak is not present or is unresolved in the zeolite without water treatment. In this respect all references in the present specification to NMR chemical shift values are determined based on the shift from the reference peak for tetramethylsilane (TMS).

[0053 J After water treatment, the MCM-22 family zeolite may be used directly as an alkylation catalyst for the production of sec-butylbenzene. Alternatively, after being contacted with water and prior to use as an alkylation catalyst, the zeolite can be dried in air or an inert gas, such as nitrogen, such as at a temperature of about 100⁰C to about 200°C for a time of about 1 hour to about 5 hours. Surprisingly, it is found that this drying step does not significantly detract from the improvement in sec-butylbenzene selectivity produced by the water contacting step.

[0054] The alkylation process is conducted such that the organic reactants, i.e., the alkylatable aromatic compound and the alkylating agent, are brought into contact with the alkylation catalyst described above under effective alkylation conditions controlled so as to maximize the conversion to sec-butylbenzene and minimize the formation of butene oligomers. In particular, a large stoichiometric excess of benzene is fed to the alkylation reaction and the local concentration of the alkylating agent is reduced preferably by staged addition of the alkylating agent. This is conveniently achieved by providing the alkylation catalyst in a plurality of fixed bed reaction zones connected in series. Most or all of the benzene is then fed to the first reaction zone, whereas the alkylating agent is divided into a plurality of equal or different aliquot portions, each of which is fed to a different reaction zone. Alternatively, the alkylation reaction can be conducted in a catalytic distillation reactor, with the alkylating agent being fed to the reactor continuously or in stages over the course of the reaction. In either case, the total amounts of benzene and alkylating agent fed to reaction are conveniently such that the overall molar ratio of benzene to alkylating agent is from about 1 to about 20, preferably about 3 to about 10, more preferably about 4 to about 9.

[0055] In addition, the alkylation conditions conveniently include a temperature of from about 60⁰C to about 260°C, for example between about 100°C and about 200⁰C and/or a pressure of 7000 kPa or less, for example from about 1000 to about 3500 kPa and/or a weight hourly space velocity (WHSV) based on C₄ alkylating agent of between about 0.1 and about 50 hr^"1, for example between about 1 and about 10 hr^'1.

[0056] The reactants can be in either the vapor phase or partially or completely in the liquid phase and can be neat, i.e., free from intentional admixture or dilution with other material, or they can be brought into contact with the zeolite catalyst composition with the aid of carrier gases or diluents such as, for example, hydrogen or nitrogen. Preferably, the reactants are at least partially in the liquid phase

[0057] Using the catalyst and alkylation conditions described above, it is found that the alkylation step of the process of the invention is highly selective to sec- butylbenzene. In particular, it is found that the alkylation product generally comprises at least 93 wt%, preferably at least 95 wt%, sec-butylbenzene and/or between about 0.01 wt% and about 1 wt%, preferably between about 0.05 wt% and about 0.8 wt% of butene oligomers and/or less than 0.5 wt% of isobutylbenzene. [0058] Although the alkylation step is highly selective towards sec-butylbenzene, the effluent from the alkylation reaction will normally contain some polyalkylated products, as well as unreacted aromatic feed and the desired monoalkylated species. The unreacted aromatic feed is normally recovered by distillation and recycled to the alkylation reactor. The bottoms from the benzene distillation are further distilled to separate monoalkylated product from any polyalkylated products and other heavies. Depending on the amount of polyalkylated products present in the alkylation reaction effluent, it may be desirable to transalkylate the polyalkylated products with additional benzene to maximize the production of the desired monoalkylated species. [0059] Transalkylation with additional benzene is typically effected in a transalkylation reactor, separate from the alkylation reactor, over a suitable transalkylation catalyst, such as a molecular sieve of the MCM-22 family, zeolite beta, MCM-68 (see U.S. Patent No. 6,014,018), zeolite Y or mordenite. Molecular sieves of the MCM-22 family include MCM-22 (described in U.S. Patent No. 4,954,325), PSH-3 (described in U.S. Patent No. 4,439,409), SSZ-25 (described in U.S. Patent No. 4,826,667), ERB-I (described in European Patent No. 0293032), ITQ-I (described in U.S.Patent No 6,077,498), ITQ-2 (described in International Patent Publication No. WO97/17290), MCM-36 (described in U.S. Patent No. 5,250,277), MCM-49 (described in U.S. Patent No. 5,236,575), MCM- 56 (described in U.S. Patent No. 5,362,697), UZM-8 (described in U.S. Patent No. 6,756,030), and mixtures thereof. The transalkylation reaction is typically conducted under at least partial liquid phase conditions, which suitably include a temperature of 100 to 300⁰C and/or a pressure of 1000 to 7000 kPa and/or a wweeiigghhtt hhoouurrllyy ssppaaccee vveelloocciittyy ooff 11 ttoo 5500 h hrr^""11 on total feed and/or a benzene/polyalkylated benzene weight ratio of 1 to 10.

Sec-Butyl Benzene Oxidation

[0060] In order to convert the sec-butylbenzene into phenol and methyl ethyl ketone, the sec-butylbenzene is initially oxidized to the corresponding hydroperoxide. This may be accomplished by introducing an oxygen-containing gas, such as air, into a liquid phase containing the sec-butylbenzene. Unlike cumene, atmospheric air oxidation of sec-butylbezene in the absence of a catalyst is very difficult to achieve. For example, at 1 10°C and at atmospheric pressure, sec-butylbenzene is not oxidized, while cumene oxidizes very well under the same conditions. At higher temperatures, the rate of atmospheric air oxidation of sec- butylbenzene improves; however, higher temperatures also produce significant levels of undesired by-products.

[0061] Improvements in the reaction rate and selectivity can be achieved by performing sec-butylbenzene oxidation in the presence of a catalyst. Suitable sec- butylbenzene catalysts include a water-soluble chelate compound in which multidentate ligands are coordinated to at least one metal from cobalt, nickel, manganese, copper, and iron (See U.S. Patent No. 4,013,725). More preferably, a heterogeneous catalyst is used. Suitable heterogeneous catalysts are described in U.S. Patent No. 5,183,945, wherein the catalyst is an oxo (hydroxo) bridged tetranuclear manganese complex and in U.S. Patent No. 5,922,920, wherein the catalyst comprises an oxo (hydroxo) bridged tetranuclear metal complex having a mixed metal core, one metal of the core being a divalent metal selected from Zn, Cu, Fe, Co, Ni, Mn and mixtures thereof and another metal being a trivalent metal selected from In, Fe, Mn, Ga, Al and mixtures thereof. The entire disclosures of said U.S. patents are incorporated herein by reference. [0062] Other suitable catalysts for the sec-butylbenzene oxidation step are the N- hydroxy substituted cyclic imides described in U.S. Patent No. 6,720,462 and incorporated herein by reference, such as N-hydroxyphthalimide, 4-amino-N- hydroxyphthalimide, 3-amino-N-hydroxyphthalimide, tetrabromo-N- hydroxyphthalimide, tetrachloro-N-hydroxyphthalimide, N-hydroxyhetimide, N- hydroxyhimimide, N-hydroxytrimellitimide, N-hydroxybenzene- 1 ,2,4- tricarboximide, N,N'-dihydroxy(pyromellitic diimide), N,N'- dihydroxy(benzophenone-3,3',4,4'-tetracarboxylic diimide), N-hydroxymaleimide, pyridine-2,3-dicarboximide, N-hydroxysuccinimide, N-hydroxy(tartaric imide), N-hydroxy-5-norbornene-2,3-dicarboximide, exo-N-hydroxy-7-oxabicyclo[2.2.1 ] hept-5-ene-2,3-dicarboximide, N-hydroxy-cis-cyclohexane-l ,2-dicarboximide, N- hydroxy-cis-4-cyclohexene-l,2 dicarboximide, N-hydroxynaphthalimide sodium salt or N-hydroxy-o-benzenedisulphonimide. Preferably, the catalyst is N- hydroxyphthalimide. Another suitable catalyst is N,N',N"-thihydroxyisocyanuric acid.

[0063] These materials can be used either alone or in the presence of a free radical initiator and can be used as liquid-phase, homogeneous catalysts or can be supported on a solid carrier to provide a heterogeneous catalyst. [0064] Suitable conditions for the sec-butylbenzene oxidation step include a temperature between about 70⁰C and about 200⁰C, such as about 90°C to about 130⁰C, and a pressure of about 50 to about 200OkPa (about 0.5 to about 20 atmospheres). A basic buffering agent may be added to react with acidic byproducts that may form during the oxidation. In addition, an aqueous phase may be introduced, which can help dissolve basic compounds, such as sodium carbonate. The per-pass conversion in the oxidation step is preferably kept below 50%, to minimize the formation of byproducts. The oxidation reaction is conveniently conducted in a catalytic distillation unit and the sec-butylbenzene hydroperoxide produced may be concentrated by distilling off the unreacted sec- butylbenzene prior to the cleavage step.

Hydroperoxide Cleavage

[0065] The final step in the conversion of the sec-butylbenzene into phenol and methyl ethyl ketone involves cleavage of the sec-butylbenzene hydroperoxide, which is conveniently effected by contacting the hydroperoxide with a catalyst in the liquid phase at a temperature of about 20⁰C to about 150⁰C, such as about 4O⁰C to about 120⁰C and/or a pressure of about 50 to about 2500 kPa, such as about 100 to about 1000 kPa and/or a liquid hourly space velocity (LHSV) based on the hydroperoxide of about 0.1 to about 100 hr^"1, preferably about 1 to about 50 hr^" . The sec-butylbenzene hydroperoxide is preferably diluted in an organic solvent inert to the cleavage reaction, such as methyl ethyl ketone, phenol or sec- butylbenzene, to assist in heat removal. The cleavage reaction is conveniently conducted in a catalytic distillation unit.

[0066] The catalyst employed in the cleavage step can be a homogeneous catalyst or a heterogeneous catalyst.

[0067] Suitable homogeneous cleavage catalysts include sulfuric acid, perchloric acid, phosphoric acid, hydrochloric acid and p-toluenesulfonic acid. Ferric chloride, boron trifluoride, sulfur dioxide and sulfur trioxide are also effective homogeneous cleavage catalysts. The preferred homogeneous cleavage catalyst is sulfuric acid

[0068] A suitable heterogeneous catalyst for use in the cleavage of sec- butylbenzene hydroperoxide includes a smectite clay, such as an acidic montmorillonite silica-alumina clay, as described in U.S. Patent No. 4,870,217, the entire disclosure of which is incorporated herein by reference.

[0069] The following Examples are given for illustrative purposes and do not limit the scope of the invention.

Example 1 (Comparative)

Sec-butylbenzene production with MCM-49/V300 catalyst dried at 15O⁰C

[0070] A sample of fresh MCM-22 catalyst, with a nominal composition of 80 wt% zeolite and 20 wt% Versal 300 (V300) alumina, was extruded to 1.3 mm (1/20 inch) diameter quadralobe form and was cut to lengths of 1.3 mm (1/20 inch).. 0.38 gram of the catalyst was diluted with sand to 3 cc and loaded into an isothermal, down-flow, fixed-bed, tubular reactor having an outside diameter of 4.76 mm (3/16"). The catalyst was dried for 2 hours at 150°C and 101 kPa (1 atm) with 100 cc/min flowing nitrogen. The nitrogen was turned off and benzene was fed to the reactor at 60 cc/hr until reactor pressure reached 2170 kPa (300 psig). Benzene flow was then reduced to 7.63 cc/hr and the temperature was adjusted to 160°C. 2-Butene feed (57.1% cis-butene, 37.8% trans-butene, 2.5% n- butane, 0.8% isobutene and 1-butene, and 1.8% others) was introduced from a syringe pump at 2.57 cc/hr or 4.2 WHSV. Feed benzene/butene molar ratio was maintained at 3: 1 for the entire run. Liquid products were collected at 160°C and 2170 kPa (300 psig) in a cold-trap and analyzed off line. Butene conversion was determined by measuring unreacted butene relative to feed butene. Additional data were collected at 14.4, 25.2, then 4.2 WHSV on butene at 160°C, 2170 kPa (300 psig), and 3: 1 benzene/butene molar ratio. Sec-butylbenzene (s-BB) selectivity vs. time on stream is shown in Figure 1. Dibutylbenzene (Di-BB)/s-BB ratio vs. time on stream is shown in Figure 2. Representative data at 85% and 97% butene conversions are shown in Tables 2 and 3, respectively.

Example 2

Sec-Butylbenzene production with humidified MCM-49/V300 catalyst

[0071] A 0.38 g aliquot of the same MCM-49 catalyst as described in Example 1 (cut to 1.3 mm (1/20 inch) length) was weighed into a sample tray. The tray with the catalyst was placed on a holding-tray inside a desiccator which contained water at the bottom. There was no direct contact between the catalyst and liquid water. The catalyst was left in the closed desiccator overnight. The final weight of the catalyst was 0.51 g. The entire amount of humidified catalyst was loaded into the reactor using the same procedure as described in Example 1 , but without the catalyst drying step. Benzene was fed to the reactor at 60 cc/hr until reactor pressure reached 2170 kPa (300 psig), and reactor temperature reached 160⁰C (ramped at 5 deg C/min). Benzene flow was then reduced to 7.63 cc/hr and the same 2-butene feed as used in Example 1 was introduced at 2.57 cc/hr or 4.2 WHSV. Feed benzene/butene molar ratio was maintained at 3: 1 for the entire run. Additional data were collected at 12.6, 25.2, then 4.4 WHSV on butene at 16O⁰C, 2170 kPa (300 psig), and 3: 1 benzene/butene molar ratio. s-BB selectivity vs. time on stream is shown in Figure 1. Di-BB/s-BB ratio vs. time on stream is shown in Figure 2. Representative data at 85% and 97% butene conversion after lineout are shown in Tables 2 and 3, respectively. Table 2. Comparison of MCM-49 Performance at 85% Butene Conversion

Dry catalyst (Example 1) Humidified catalyst (Example 2)

Days on Stream 39 40 41 79 80 8 I

Benzene WHSV, h ' 1050 1050 1050 1050 1050 1050

Butene WHSV h ' 252 252 252 252 252 252

Butene Conversion, % 846 833 835 874 843 85 I

Product Selectivity, wt % ι-Butane 0001 0001 0001 0000 0000 0000

Isobutene + 1 -Butene 0411 0413 0416 0280 0373 0310

C₅-C₇ 0079 0077 0066 0061 0105 0057

C₈= 1285 1332 1255 0969 1083 1031

C9-11 0047 0059 0058 0034 0032 0032

C|₂= + C₁₀-Cn Arom 0106 0095 0103 0077 0072 0078

Cιri5 0085 0091 0092 0076 0066 0069

Cumene 0022 0021 0021 0025 0023 0023 t-Butylbenzene 0031 0029 0029 0039 0032 0032 i-Butylbenzene * 0000 0000 0000 0000 0000 0000 s-Butylbenzene 91.203 90.969 90.955 94.137 94.080 94.027 n-Butylbenzene 0007 0011 0008 0007 0011 0010

Dibutylbenzenes 6418 6588 6682 4101 3973 4174

Tπbutylbenzenes 0291 0304 0303 0181 0140 0150

Heavies 0014 0010 0011 0014 0011 0005

Sum 1000 1000 1000 1000 1000 1000 s-BB Puπtv, % t-BB/allBB, % 0034 0032 0032 0042 0034 0034 ι-BB*/a!l BB, % 0000 0000 0000 0000 0000 0000 s-BB/all BB, % 99959 99957 99960 99951 99955 99955 n-BB/al! BB % 0007 0012 0008 0007 0011 0011

Sum, % 1000 1000 1000 1000 1000 1000

Di-BB/s-BB Wt Ratio, % 70 72 73 44 42 44

1 st-order rate constant, h ' 46 49

All samples collected at 160⁰C, 2170 kPa (300 psig), and 31 benzene/butene molar ratio * iso-Butylbenzene less than 05% in total butylbenzene is not detectable with GC used Table 3. Comparison of MCM-49 Performance at 97% Butene Conversion

Dry catalyst (Example I) Humidified catalyst (Examole

Days on Stream 4.8 5.8 6.8 8.8 9.8 10.8

Benzene WHSV, h^" 17.5 17.5 17.5 17.5 17.5 17.5

Butene WHSV. h^"1 4.2 4.2 4.2 4.2 4.2 4.2

Butene Conversion. 96.7 96.5 96.7 96.7 96.4 96.5

Product Selectivity, i-Butane 0.001 0.001 0.001 0.001 0.001 0.001

Isobutene + 1 - 0.000 0.000 0.000 0.000 0.000 0.000

Cs-C₇ 0.063 0.061 0.060 0.057 0.055 0.047

Cs= 0.715 0.691 0.690 0.469 0.458 0.501

Cq-| I 0.033 0.050 0.054 0.016 0.025 0.025 + C|θ-C| | 0.102 0.152 0.130 0.101 0.1 13 0.1 13

Cπ-i¹! 0.101 0.215 0.101 0.105 0.076 0.130

Cumene 0.028 0.030 0.030 0.034 0.036 0.035 t-Butylbenzene 0.062 0.067 0.065 0.080 0.086 0.084 i-Butylbenzene * 0.000 0.000 0.000 0.000 0.000 0.000 s-Burvlbenzene 92.311 92.075 92.213 94.837 94.949 94.524 n-Butylbenzene 0.007 0.01 1 0.01 1 0.008 0.009 0.008

Dibutylbenzenes 5.933 5.910 6.029 4.046 3.966 4.273

Tributylbenzenes 0.475 0.575 0.426 0.239 0.220 0.251

Heavies 0.170 0.161 0.188 0.005 0.005 0.009

Sum 100.0 100.0 100.0 100.0 100.0 100.0 s-Butylbenzene t-BB/all BB, % 0.068 0.073 0.071 0.084 0.091 0.088 i-BB*/all BB, % 0.000 0.000 0.000 0.000 0.000 0.000 s-BB/all BB, % 99.925 99.915 99.917 99.908 99.900 99.903 n-BB/all BB, % 0.008 0.012 0.012 0.008 0.009 0.008

Sum, % 100.0 100.0 100.0 100.0 100.0 100.0

Di-BB/s-BB Wt 6.4 6.4 6.5 4.3 4.2 4.5

1 st-order rate 46 49

All samples collected at 160°C, , 2170 kPa (300 psig), and 3: 1 benzene/butene molar ratio. * iso-Butylbenzene less than 0.5% in total butylbenzene is not detectable with our GC.

[0072] Referring to Figure 1 , it will be seen that the dried catalyst of Example 1 made s-BB with 90% selectivity at startup and gradually improved selectivity to 92% at steady-state operation. In contrast, the humidified catalyst of Example 2 produced s-BB with 94% selectivity right after startup and remained at 94-95% through out the entire run. Referring to Figure 2, it will be seen that the dried catalyst of Example 1 produced twice as much di-BB as the humidified catalyst of Example 2 at startup, and the di-BB level remained 2 wt% higher at steady-state operation. Thus using humidified MCM-49 without drying eliminated the lineout period where higher di-BB is produced and provided 2% higher s-BB selectivity at steady-state operation.

|00731 Table 2 shows that, when compared to the dried MCM-49 at 85% butene conversion, the humidified catalyst produced 3% more s-BB (94% vs. 91 %) and much less butene oligomers and polybutylbenzenes. The first-order rate constants (see bottom of Table 2, calculated based on butene conversion) indicate that humidification had no negative impact on catalyst activity. In fact, the humidified catalyst had a slightly higher rate constant than the dried catalyst. [0074] Similarly, Table 3 shows that, when compared to dried MCM-49 at 97% butene conversion, the humidified catalyst produced 3% more s-BB (95% vs. 92%) and much less butene oligomers, polybutylbenzenes, and heavies. Humidification apparently modified catalyst activity, eliminated the lineout period, reduced byproduct formation, and improved s-BB selectivity.

Example 3 (Comparative)

Sec-butylbenzene production with MCM-49/V300 catalyst without drying or humidication

[0075] A 0.20 g aliquot of the same MCM-49 catalyst as described in Example 1 (cut to 1.3 mm (1/20 inch) length) was loaded into the reactor using the same procedure described in Example 1. The catalyst was used without drying. Benzene was fed to the reactor at 60 cc/hr until reactor pressure reached 2170 kPa (300 psig), and reactor temperature reached 160°C (ramped at 5 deg C/min). Benzene flow was then reduced to 7.63 cc/hr. 2-Butene was introduced at 2.57 cc/hr or 8.0 WHSV. Data were collected at 160°C, 2170 kPa (300 psig),, and 3:1 benzene/butene molar ratio. 95% butene conversion was observed at 8 WHSV, 73% butene conversion at 24 WHSV, and 67% butene conversion at 48 WHSV. First-order rate constant based on butene conversion was 51 h^"1. s-BB selectivity vs. time on stream is shown in Figure 3a. Di-BB/s-BB ratio vs. time on stream is shown in Figure 3b. For comparison, data for Examples 1 and 2 are also included. These data show that MCM-49 catalyst whether it is dried or not before startup provided lower s-BB selectivity and higher di-BB selectivity than its humidified version. Example 4

Sec-butylbenzene production with water-soaked MCM-49/V300 catalyst

[0076] A 0.20 g aliquot of the same MCM-49 catalyst as described in Example 1 (cut to 1.3 mm (1/20) inch length) was soaked at room temperature with de- ionized water for 1 hour, then air-dried overnight also at room temperature. The final weight of the catalyst was 0.26 g. The entire amount of catalyst was loaded into the reactor using the same procedure as described in Example 1. The catalyst was used without further drying. Benzene was fed to the reactor at 60 cc/hr until reactor pressure reached 2170 kPa (300 psig), and reactor temperature reached 160°C (ramped at 5 deg C/min). Benzene flow was then reduced to 7.63 cc/hr. 2-Butene was introduced at 2.57 cc/hr or 8 WHSV. Data were collected at 160⁰C, 2170 kPa (300 psig),, and 3: 1 benzene/butene molar ratio. 97% butene conversion was achieved at 8 WHSV, 83% butene conversion at 24 WHSV, and 67% butene conversion at 48 WHSV. First-order rate constant based on benzene conversion was 45 h^"1. s-BB selectivity vs. time on stream is shown in Figure 4a. Di-BB/s- BB ratio vs. time on stream is shown in Figure 4b. For comparison, data for Examples 1 to 3 are also included. These data show that water-soaking is as effective as humidity treatment to modify MCM-49 to achieve high s-BB selectivity and lower di-BB selectivity.

Example 5

Sec-butylbenzene production with humidified then dried MCM-49/V300 catalyst [0077] A 0.20 g aliquot of the same MCM-49 catalyst as described in Example 1 (cut to 1.3 mm (1/20 inch) length) was humidified using the same procedure described in Example 2. The final weight of the catalyst was 0.30 g after humidification. The entire amount of humidified catalyst was loaded the reactor using the same procedure as described in Example 1. The catalyst was dried at 150°C and 101 kPa (1 atm) with 100 cc/min flowing nitrogen for 2 hours. Nitrogen was turned off and benzene was fed to the reactor at 60 cc/hr until reactor pressure reached 2170 kPa (300 psig),. Reactor temperature was adjusted to 160°C and benzene flow was reduced to 7.63 cc/hr. 2-Butene was introduced at 2.57 cc/hr or 8 WHSV. Data were collected at 160°C, 2170 kPa (300 psig),, and 3: 1 benzene/butene molar ratio. 95% butene conversion was achieved at 8 WHSV, 80% butene conversion at 24 WHSV, and 66% butene conversion at 48 WHSV. First-order rate constant based on butene conversion was 42 h^'1. s-BB selectivity vs. time on stream is shown in Figure 5a. Di-BB/s-BB ratio vs. time on stream is shown in Figure 5b. For comparison, data for Examples 1 to 4 are also included. The data show that although this humidified catalyst was dried at 150°C before startup, its s-BB selectivity remained high and its di-BB remained low.

[0078] Table 4 compares the performance of the catalysts of Examples 1 to 5 at 92-97% butene conversion and steady-state conditions. When compared to untreated MCM-49, humidity/water treatment produced 3% more s-BB (95% vs. 92%) and less butene oligomers, dibutylbenzenes, tributylbenzenes and heavies. Humidification apparently modified catalyst activity, eliminated the lineout period, reduced byproduct formation, and improved s-BB selectivity.

Table 4. Comparison of MCM-49/V300 Performance

Example 3 1 2 5 4

Treatment No No Humidity Humidity Water

Drying at 150°C No Yes No Yes No

Days on Stream 4.9 6.8 10.8 1.8 2.8

Benzene WHSV 32.8 17.4 17.5 33.0 33.1

Butene WHSV 7.9 4.2 4.2 7.9 7.9

Butene Conversion, % 92.4 96.7 96.5 94.2 96.4

Product Selectivity, wt % i-Butane 0.001 0.001 0.001 0.001 0.001

Isobutene + 1 -Butene 0.023 0.000 0.000 0.039 0.000

C₅-C₇ 0.099 0.093 0.079 0.066 0.056

C₈= 0.755 0.690 0.501 0.413 0.500

C9-11 0.050 0.054 0.025 0.051 0.025

C|₂= + Cio-Ci i Arom. 0.1 15 0.130 0.1 13 0.1 14 0.090

Ci₃-I₅ 0.055 0.101 0.130 0.095 0.100

Cumene 0.023 0.030 0.035 0.022 0.026 t-Butylbenzene 0.042 0.065 0.084 0.083 0.051 i-Butylbenzene * 0.000 0.000 0.000 0.000 0.000 s-Butylbenzene 91.682 92.183 94.493 94.377 94.430 n-Butylbenzene 0.006 0.01 1 0.008 0.014 0.006

Dibutylbenzenes 6.397 6.027 4.271 4.536 4.538

Tributylbenzenes 0.440 0.426 0.251 0.158 0.166

Heavies 0.312 0.188 0.009 0.030 0.01 1

Sum 100.0 100.0 100.0 100.0 100.0 s-Butvlbenzene (BB) t-BB/all BB, % 0.045 0.071 0.088 0.088 0.054 i-BB*/all BB, % 0.000 0.000 0.000 0.000 0.000 s-BB/all BB, % 99.948 99.917 99.903 99.897 99.939 n-BB/all BB, % 0.007 0.012 0.008 0.015 0.007

Sum, % 100.0 100.0 100.0 100.0 100.00

Di-BB/s-BB Wt Ratio, % 7.0 6.5 4.5 4.8 4.8

1 st-order rate constant, h^' 52 46 49 42 45

All samples collected at 160⁰C, 2170 kPa (300 psig), sig, and 3: 1 benzene/butene molar ratio. * iso-Butylbenzene less than 0.5% in total burylbenzene is not detectable with our GC. Example 6 (Comparative)

Sec-butylbenzene production with dried MCM-49/Condea catalyst

[0079] A sample of fresh MCM-49 catalyst, with a nominal composition of 80 wt% zeolite and 20 wt% Condea alumina, was extruded to 1.3 mm (1/20 inch) diameter quadralobe form and was cut to lengths of 1.3 mm (1/20 inch). 0.40 gram of the catalyst was diluted with sand to 3 cc and loaded into an isothermal, down-flow, fixed-bed, tubular reactor having an outside diameter of 4.76 mm (3/16"). The catalyst was dried for 2 hours at 150°C and 101 kPa (1 atm) with 100 cc/min flowing nitrogen. Nitrogen was turned off and benzene was fed to the reactor at 60 cc/hr until the reactor pressure reached 2170 kPa (300 psig),. Reactor temperature was adjusted to 160⁰C and benzene flow was reduced to 7.63 cc/hr. 2-Butene feed was introduced at 2.57 cc/hr or 4 WHSV. Feed benzene/butene molar ratio was 3:1 for the entire run. s-BB selectivity vs. time on stream is shown in Figure 6a. Di-BB/s-BB ratio vs. time on stream is shown in Figure 6b.

Example 7

Sec-butylbenzene production with humidified MCM-49/Condea catalyst

[0080] A 0.20 g aliquot of the fresh MCM-49/Condea catalyst employed in Example 6 was humidified using the same procedure described in Example 2. The final weight of the catalyst was 0.35 g after humidification. The entire amount of humidified catalyst was loaded into the reactor with the same procedure as described in Example 1. The catalyst was used without drying. Benzene was fed to the reactor at 60 cc/hr until reactor pressure reached 2170 kPa (300 psig), and the reactor temperature reached 160⁰C (ramped at 5 deg C/min). Benzene flow was reduced to 7.63 cc/hr. 2-Butene was introduced at 2.57 cc/hr or 8.0 WHSV. Feed benzene/butene molar ratio was 3: 1 for the entire run. s-BB selectivity vs. time on stream is shown in Figure 6a. Di-BB/s-BB ratio vs. time on stream is shown in Figure 6b. [0081] Referring to Figures 6a and 6b, the data show that before humidity treatment, the MCM-49/Condea catalyst had very low s-BB selectivity and very high di-BB selectivity. It would probably have taken 2 weeks to eventually reach steady-state performance. After humidity treatment, s-BB selectivity improved significantly to the 94-95% level, comparable to that of the humidified MCM- 49/Versal 300 catalyst as shown in Example 2. [0082) Table 5 compares performance of the catalysts of Examples 6 and 7 at 95- 98% butene conversion. When compared to the dry catalyst, the humidified version produced 6% more s-BB (95% vs. 89%), reduced byproducts (including butene oligomers, dibutylbenzenes, and tributylbenzenes) to half, reduced cumene and heavies formation to nil, and significantly reduced t-BB and n-BB formation. Humidification apparently modified catalyst activity, eliminated the lineout period, reduced byproduct formation, and significantly improved s-BB selectivity.

Table 5. Comparison of MCM-49/Condea Performance

Dry catalyst (Example 6) Humidified catalyst (Example

Sample # 7 8 9 7 8 9

Days on Stream 7.1 8.1 9.1 6.8 7.8 8.8

Benzene WHSV, h^{" 1} 16.7 16.7 16.7 33.2 33.2 33.2

Butene WHSV, h^"' 4.0 4.0 4.0 8.0 8.0 8.0

Butene Conversion, % 95.4 95.3 96.3 97.7 95.9 96.4

Product Selectivity, wt % i-Butane 0.005 0.006 0.005 0.000 0.000 0.000

Isobutene + 1 -Butene 0.000 0.000 0.000 0.000 0.000 0.000

C₅-C₇ 0.101 0.1 15 0.109 0.046 0.099 0.064

C₈= 1.154 1.225 1.374 0.571 0.606 0.671

C₉-H 0.091 0.088 0.098 0.018 0.007 0.038

C|₂= + Ci₀-C_n Arom. 0.283 0.276 0.272 0.074 0.074 0.052

C |3"15 0.373 0.327 0.320 0.076 0.084 0.060

Cumene 0.290 0.288 0.286 0.000 0.020 0.000 t-Butylbenzene 0.164 0.158 0.146 0.047 0.045 0.042 i-Butylbenzene * 0.000 0.000 0.000 0.000 0.000 0.000 s-Butylbenzene 88.096 88.644 89.005 94.828 94.725 95.031 n-Butylbenzene 0.019 0.017 0.025 0.002 0.001 0.000

Dibutylbenzenes 8.583 8.124 7.597 4.280 4.291 4.002

Tributylbenzenes 0.767 0.669 0.599 0.059 0.049 0.039

Heavies 0.075 0.063 0.163 0.000 0.000 0.001

Sum 100.0 100.0 100.0 100.0 100.0 100.0 s-Burylbenzene (BB) Purity, t-BB/all BB, % 0.185 0.178 0.164 0.049 0.047 0.044 i-BB*/all BB, % 0.000 0.000 0.000 0.000 0.000 0.000 s-BB/all BB, % 99.794 99.803 99.808 99.949 99.952 99.956 n-BB/all BB, % 0.021 0.019 0.028 0.002 0.001 0.000

Sum, % 100.0 100.0 100.0 100.0 100.0 100.0

Di-BB/s-BB Wt Ratio, % 9.7 9.2 8.5 4.5 4.5 4.2

All samples collected at 160⁰C, 2170 kPa (300 psig),, and 3: 1 benzene/butene molar ratio. * Iso-Butylbenzene less than 0.5% in total butylbenzene is not detectable with our GC. Example 8

Comparison of Catalysts by ²⁹Si MAS NMR

[0083] Samples of the 150°C-dried and humidified catalysts described in Examples 1 and 2, respectively, were further characterized by ²⁹Si MAS NMR. The ²⁹Si MAS NMR data for these two materials are given in Figure 7. These ²⁹Si MAS NMR data clearly show differences that reflect the structural changes that occur upon dehydration or hydration. In particular, the ²⁹Si MAS NMR spectrum for the humidified catalysts described in Example 2 exhibits a peak at a chemical shift range of -90 to -100 ppm from TMS, more particularly at a chemical shift range of about -94 to -100, with the high point of the peak as shown being around -98 ppm from TMS. This peak is generally unresolved in the spectrum for the dried catalyst of Example 1. The differences in the NMR spectra are a reflection of the changes in the local environments of the Si, such as bond angles and nearest neighbor population, that are dependent on the level of hydration. These data suggest that wetting the sample promotes re-insertion of Al into the tetrahedral framework and/or a relaxation of the local geometric strains that are induced by dehydration. These subtle structural changes may account for the improved activity and selectivity of the hydrated catalyst.

Example 9 (Comparative)

Sec-butylbenzene production with dried and hydrated beta/alumina catalyst

[0084] A fresh zeolite beta catalyst, with a nominal composition of 65 wt% zeolite and 35 wt% Versal 300 alumina, was extruded to 1.3 mm diameter quadralobe form and was cut to lengths of 2 mm. [0085] One sample of the zeolite beta catalyst was used in the alkylation of benzene with the 2-butene feed of Example 1 using the procedure of Example 1 , that is with the catalyst being dried for 2 hours at 150°C and 101 kPa (1 atm) with 100 cc/min flowing nitrogen before contacting the benzene and butene feeds. Feed benzene/butene molar ratio was maintained at 3: 1 for the entire run and liquid products were collected at 16O⁰C and 2170 kPa (300 psig), in a cold-trap and analyzed off line. The results are summarized in Table 6. [0086] A further sample of the zeolite beta catalyst was used in the alkylation of benzene with the 2-butene feed of Example 1 using the procedure of Example 2, that is with the catalyst being humidified in a closed desiccator overnight before contacting the benzene and butene feeds. Feed benzene/butene molar ratio was again maintained at 3: 1 for the entire run and liquid products were collected at 160°C and 2170 kPa (300 psig),in a cold-trap and analyzed off line. The results are also summarized in Table 6.

Table 6. Comparison of Zeolite Beta Performance

Dry catalyst Humidified catalyst

Da> s on Stream 0 83 1 83 2 83 0 79 I 79 2 79

Benzene WHSV, h ' 33 2 33 2 33 2 33 0 33 0 33 0

Butene WHSV, h ' 8 0 8 0 8 0 7 9 7 9 7 9

Butene Conversion, % 91 21 60 23 44 64 82 79 49 49 41 88

Product Selectivity, vvt % ι-Butane 0 004 0 003 0 000 0 006 0 000 0 003

Isobutene + 1 -Butene 0 21 1 3 478 9 208 0 812 6 065 9 301 c,-c₇ 0 159 0 250 0 346 0 139 0 321 0 398

C₈= I 039 8 652 12 575 2 721 1 1 460 12 393

0 198 0 670 0 284 0 445 0 470 0 341

C]₂= + C|o-C| | Arom 0 226 0 813 0 271 0 795 0 352 0 408

C |₃-| ₅ 0 361 0 088 0 025 0 587 0 025 0 021

Cumene 0 019 0 000 0 000 0024 0000 0 002 t-Butylbenzene 0 255 0 077 0 012 0 288 0 025 0 010 i-Butylbenzene * 0 000 0 000 0 000 0 000 0 000 0 000 s-Butylbenzene 85.316 80.627 74.829 81.370 76.713 73.999 n-Butylbenzene 0 006 0 017 0 000 0 093 0 1 13 0 000

Dibutylbenzenes 10 361 5 052 2 390 10 974 4 240 2 902

Tributylbenzenes 1 174 0 194 0 01 1 1 422 0 1 14 0 105

Heavies 0 672 0 079 0 049 0 325 0 103 0 1 16

Sum 100 0 100 0 100 0 100 0 100 0 100 0 s-BB Purity, % t-BB/all BB, % 0 298 0 095 0 016 0 352 0 033 0 013 i-BBVall BB, % 0 000 0 000 0 000 0 000 0 000 0 000 s-BB/ail BB, % 99 696 99 884 99 984 99 534 99 821 99 987 n-BB/all BB, % 0 007 0 021 0 000 0 1 13 0 147 0 000

Sum, % 100 0 100 0 100 0 100 0 1000 100 0

Di-BB/s-BB Wt Ratio, % 12 14 6 27 3 19 13 49 5 53 3 92

All samples collected at 16O⁰C, 21 70 kPa (300 psig),, and 3 I benzene/butene molar ratio * iso-Butylbenzene less than 0 5% in total butylbenzene is not detectable with GC used.

[0087] From the results in Table 6 it will be seen that, at the 3.1 benzene/butene molar ratio used in the test, the zeolite beta catalyst, both when dried and humidified, deactivated rapidly through the formation of oligomers. Moreover, unlike the MCM-49 catalyst employed in Examples 1 and 2, humification of the zeolite beta catalyst did not result in an initial increase in s-BB selectivity and an initial decrease in di-BB selectivity. On the contrary humidification of the zeolite beta catalyst resulted in a lower s-BB selectivity and a higher di-BB selectivity on start-up as compared with the dried catalyst. [0088] While the present invention has been described and illustrated by reference to particular embodiments, those of ordinary skill in the art will appreciate that the invention lends itself to variations not necessarily illustrated herein. For this reason, then, reference should be made solely to the appended claims for purposes of determining the true scope of the present invention.

Claims

1. A process for producing sec-butylbenzene, the process comprising reacting benzene with at least one C₄ alkylating agent under alkylation conditions and in the presence of a catalyst comprising at least one molecular sieve of the MCM-22 family to produce an alkylation product comprising sec-butylbenzene, wherein, prior to said reacting, said catalyst is contacted with water under conditions to improve the sec-butylbenzene selectivity of the catalyst.

2. The process of claim 1 , wherein said contacting with water is conducted under conditions including at temperature of at least 0⁰C,

3. The process of claim 2, wherein the temperature is in the range of from 10°C to 50°C.

4. The process of any preceding claim, wherein said contacting with water is conducted under conditions including for a time of at least 0.5 hour.

5. The process of claim 4, wherein the time is in the range of from 2 hours to 24 hours.

6. The process of claim 1 or 2, wherein said contacting with water is conducted under conditions sufficient to produce changes in the amplitude or width of at least one peak in the ²⁹Si MAS NMR spectrum of the catalyst in the chemical shift range of -80 to -120 ppm from tetramethylsilane (TMS).

7. The process of any preceding claim, wherein said catalyst is contacted with liquid water.

8. The process of any one of claims 1 to 6, wherein said catalyst is contacted with water vapor.

9. The process of any preceding claim, wherein said catalyst is dried after being contacted with water and prior to said reacting.

10. The process of claim 9, wherein said catalyst is dried at temperature in the range of from 100°C to 200°C for a time in the range of from 1 hour to 5 hours.

1 1. The process of any preceding claim wherein the sec-butylbenzene selectivity of the water-contacted catalyst is at least 1 wt% greater than the sec- butylbenzene selectivity of an identical catalyst that has not been contacted with water, for identical reactants and processs conditions.

12. The process of claim 1 1, wherein the sec-butylbenzene selectivity of the water-contacted catalyst is at least 2 wt% greater than the sec-butylbenzene selectivity of an identical catalyst that has not been contacted with water, for identical reactants and process conditions.

13. The process of any preceding claim, wherein said C₄ alkylating agent comprises a linear butene.

14. The process of claim 13, wherein said linear butene comprises butene-1 , butene-2 or a mixture thereof.

15. The process of claim 13 or 14 wherein said linear butene is contained in a mixed C₄ stream.

16. The process of any preceding claim, wherein the molecular sieve of the MCM-22 family has an X-ray diffraction pattern including d-spacing maxima at 12.4±0.25, 6.9±0.15, 3.57±0.07 and 3.42±0.07 Angstrom.

17. The process of any preceding claim, wherein the molecular sieve is selected from MCM-22, PSH-3, SSZ-25, ERB-I , ITQ-I, ITQ-2, MCM-36, MCM- 49, MCM-56, UZM-8, and mixtures thereof.

18. The process of any preceding claim, wherein the molecular sieve is selected from MCM-49, MCM-56 and isotypes thereof.

19. The process of any preceding claim, wherein said alkylation conditions include an overall molar ratio of benzene to C₄ alkylating agent from 1 : 1 to 20: 1.

20. The process of claim 19, wherein the overall molar ratio is from 4: 1 to 9: 1.

21. The process of claim 19 or 20, wherein said alkylation conditions also include a temperature of from 60°C to 260°C and/or a pressure of 7000 kPa or less and/or a feed weight hourly space velocity (WHSV) based on C₄ alkylating agent of from 0.1 to 50 hr^"'.

22. The process of any preceding claim, wherein said reacting is conducted in a catalytic distillation reactor.

23. The process of any preceding claim, wherein said C₄ alkylating agent is added to the process in stages.

24. The process of any preceding claim, wherein said reacting is conducted under at least partial liquid phase conditions.

25. The process of any preceding claim and further comprising oxidizing the sec-butylbenzene to produce a hydroperoxide and cleaving the hydroperoxide to produce phenol and methyl ethyl ketone.

26. The process of claim 25, wherein oxidizing the sec-butylbenzene is conducted in the presence of a catalyst.

27. The process of claim 26, wherein the catalyst is heterogeneous.

28. The process of claim 27 wherein the heterogeneous catalyst comprises a metal oxide catalyst.

29. The process of claim 26, wherein the catalyst is homogeneous.

30. The process of claim 29 wherein the homogeneous catalyst comprises an N-hydroxy substituted cyclic imide.

31. The process of claim 29 or 30 wherein the homogeneous catalyst comprises N-hydroxyphthalimide.

32. The process of any one of claims 25 to 31, wherein the oxidizing is conducted at a temperature of 70°C to 200°C and/or a pressure of 50 to 2000 kPa (0.5 to 20 atmospheres).

33. The process of any one of claims 25 to 32, wherein the cleaving of the hydroperoxide is conducted in the presence of a catalyst.

34. The process of claim 33, wherein the cleaving catalyst is homogeneous.

35. The process of claim 34, wherein the homogeneous catalyst comprises at least one of sulfuric acid, perchloric acid, phosphoric acid, hydrochloric acid, p- toluenesulfonic acid, ferric chloride, boron trifluoride, sulfur dioxide and sulfur trioxide.

36. The process of claim 33, wherein the cleaving catalyst is heterogeneous.

37. The process of claim 36, wherein the heterogeneous catalyst comprises a smectite clay.

38. The process of any one of claims 25 to 37, wherein the cleaving of the hydroperoxide is conducted at a temperature of 40⁰C to 120°C and/or a pressure of 100 to 1000 kPa and/or a liquid hourly space velocity (LHSV) based on the hydroperoxide of 1 to 50 hr^"1.