JPS5821636A - Preparation of acetal - Google Patents

Abstract

PURPOSE:In reacting an olefin with an alcohol and an ester of nitrous acid, to obtain the titled substance useful as a raw material for synthesizing agricultural chemicals, etc. by a simple operation in high yield, by contacting them in a gaseous phase in the presence of both a platinum group metal and an iron compound. CONSTITUTION:An olefin such as ethylene, propylene, etc. is brought into contact with an alcohol and an ester of nitrous acid using a platinum group metal such as palladium, platinum, etc. or their hydrochlorides as a catalyst and an iron compound as a cocatalyst in a gaseous phase, to give an acetal. The reaction is carried out usually in a temperature range of 50-200 deg.C at normal pressure or under pressure, for example, at <=20kg/cm<2> (gauge). FeCl2, FeCl3.6H2O, FeBr3, etc. are useful as the iron compound, and its amount used is an amount to give an atom ratio of iron to the platinum group metal or 0.1-10, preferably 0.5-5.

Description

[Detailed description of the invention] The present invention relates to a new method for producing acetal.

Acetals have a variety of industrial uses, such as as organic solvents, raw materials for the synthesis of fragrances and agricultural chemicals, and by dealcoholization to produce vinyl ethers, which are raw materials for water-soluble polymers.

Traditionally, acetals have been produced industrially by reactions between alcohols and aldehydes, or by oxidizing alcohols.

711 o, j engineering, Yoyori □ built.

Also olefins, alcohols and oxygen.

Various methods for producing acetals are also known in which the reaction is carried out in the presence of a platinum group metal catalyst. However, in all methods for producing acetal by this reaction, the reaction rate is slow, the yield and selectivity of the target product are poor, or the catalyst system is complex and operations such as separation, recovery, and regeneration are complicated. However, it has not been put into practical use due to the following industrial problems.

The present inventors conducted extensive research with the aim of establishing a method for producing acetal that can improve the above problems and can be applied industrially.

As a result, olefins, alcohols and nitrite esters are combined with (a) platinum group metals or salts thereof.

and (1)) if it is brought into contact with the gas phase in the coexistence of an iron compound.

All the problems of the above-mentioned known methods have been improved.

It has been discovered that acetal can be produced very industrially and advantageously.

Specific examples of olefins in the present invention include:

Aliphatic olefins such as ethylene, propylene, butene, isobutylene; Olefin aldehydes such as acrolei/, croto/aldehyde; Olefin ketones such as methyl vinyl ketone, ethylide/aceto/, allyl methyl ketone; acrylonitrile, methacrylonitrile, croto/ Olefin nitrile such as nitrile; acrylic acid,
Olefin carboxylic acids and their esters such as methacrylic acid, crotonic acid, cinnamic acid; acrylamide°.

Examples include olefin amides such as methacrylamide; alicyclic olefins such as cyclopentene, cyclohexene, and cycloheptene; and styrene.

Alcohols include methanol and ethanol.

n-(or 1-)prono(nol, n-(or 1-)
) butanol, 5ec-butanol, n-(or 1-) pentanol, n-(or 1-) hexanol, n-(or 1-) heptatool.

n- (or 1-) octatool, n- (or 1-)
Aliphatic alcohols having 1 to 12 carbon atoms are used, such as decanol and n-(or 1-)dodecanol.

These alcohols can also have substituents that do not inhibit the reaction, such as an alkoxyl group, a halogen atom, or a phenyl group.

Also, useful nitrite esters include esters of the alcohol and nitrous acid, such as methyl nitrite.

Ethyl nitrite, propyl nitrite, butyl nitrite.

Amyl nitrite, hexyl nitrite, heptyl nitrite.

Examples include nonyl nitrite, decyl nitrite, hexadecyl nitrite, and benzyl nitrite.

The proportions of these olefins, alcohols, and nitrites in the gas phase can vary within a wide range,9 but typically:
Olefins are 5-25 Vo1%.

Alcohol 5-25 Vow%, nitrite ester power 1
~30 VOI chi.

These may be supplied to the two reaction systems singly or in combination.7 They are usually supplied diluted with a gas inert to the reaction, such as nitrogen gas or carbon dioxide gas.

Note that instead of nitrite ester, nitrogen oxide or its hydrate may be supplied to the reaction system together with oxygen gas as needed.
Nitrite esters may be formed by reaction with alcohol in-system.

As the catalyst in the present invention, platinum group metals such as palladium, platinum, rhodium, and ruthenium, or salts of these metals such as hydrochlorides, sulfates, nitrates, phosphates, and acetates are used. These can also be used in combination with appropriate amounts of metals such as gold, vanadium, molybdenum, or salts thereof.

These platinum group metals or their salts, along with iron compounds as co-catalysts, include activated carbon, silica gel, alumina, silica alumina, silicon carbide, and diatomaceous earth.

It is used by being supported on a carrier such as magnesia, pumice, or molecular sheep. In this case, the amount of platinum group metal relative to the carrier is o, o 1wt* or more, preferably 0.1
It is preferable to carry it so that it is in the range of ~10 wt%.

Examples of iron compounds include FeCl21 Fe043.
FeCl2・4H20+FeC! t3-6H20,Fe
Br31 Fed, Fe2O3, Fe3O4, Fe(
OH)atF'5(303,Fe2(804)3.F
'e(NO3)3.9H20 etc. are useful.

These iron compounds have an atomic ratio of iron to platinum group metals,
It is preferable to use the amount in the range of 0.1 to io, preferably 0.5 to 5.

In addition, when using iron compounds other than iron halides, lHC6I HBr, H, 8nC64, CaC
l2. CrCts+N1ct2. MoCt3+ A
tC1310aC! /% of t2+ M1i'Bra etc.
The tff genide has a dulam ion amount of halogen ions of 0.1 to 10 with respect to the total dulam atoms of platinum group metals and iron.
It is preferable to use double the amount.

In the method of the present invention, it is preferable to carry out the reaction within the range of usually 50 to 200°C, and the pressure is from normal to pressurized, e.g.
It is carried out under pressure up to 0 Kp/cfA (gauge).

Furthermore, the rate of acetal production can be further increased by introducing oxygen into the reaction system.

In the present invention. The space velocity (sv) at which the raw material gas is brought into contact with the catalyst layer is preferably in the range of 500 to 5,000/hour.

Next, nine examples of the present invention will be described.

Table 1 *i HCut is r 50Vo1%Hc diluted with Nl
t and was supplied together with the raw material mixed gas at a rate of + + llj/min.

Example 13 From the top of the reactor, a raw material mixed gas consisting of 1 avo 1 qb of cyclohexene, 14 VO 1 methyl nitrite, 14 VO 1% oxygen, 15 VO 1% -nitrogen oxide, and 39 VO 1% nitrogen was added at 20.4 t/hr + methanol (liquid). Each speed of 9 m/hr (space velocity, 169 o/hr)
An experiment was conducted in the same manner as in Example 1, except that the reaction temperature was 95°C.

As a result, 1,1-dimethoxycyclohexane was obtained as an acetal with a space-time yield of 16.4 t/l-cat-hr.

Example 14 Methyl acrylate 18v01% from the top of the reactor.

A raw material mixed gas consisting of 18 VO 1% of oxygen, 2 q VO 1% of nitrogen oxide and 3 s VO 1% of nitrogen is 16-
61/hr.

Methyl nitrite (gaseous) at 3t/hr and methanol (liquid) at 9+tl! /hr each velocity (space velocity, 1
An experiment was conducted in the same manner as in Example 1, except that the reaction temperature was 85°C.

As a result, methyl 3,3-dimethoxypropionate was obtained as an acetal with a space-time yield of 130 f/1-cat-hr.

Example 15 From the top of the reactor, propylene 18. VO1% + nitrous acid l
An experiment was conducted in the same manner as in Example 1, except that fk 14 Vo1%, oxygen 14 Vo1%, -nitrogen oxide 15 (space velocity, 16 q o/hr) were supplied, and the reaction temperature was 97 ° C. Ta.

As a result, acetone di-n-butyl acetal was obtained as an acetal with a space-time yield of 75 t/1-cat-hr.

Example 16 Acrylonitrile 15 VO 1% from the top of the reactor.

Ethyl nitrite 15Vol, ethanol 18VO'1%
, 11 vol of oxygen, 16 vol of nitrogen oxide, and 25 vol of nitrogen at 48 t/h.
Supply at a speed of r (space velocity, 3200/hr),
Further, an experiment was conducted in the same manner as in Example 1, except that the reaction temperature was 75°C.

As a result, cyanoacetaldehyde diethyl acetal was obtained as an acetal with a space-time yield of 33 f/l -cat-hr.

Example 17 From the top of the reactor, methyl nitrite 14 Vo 1%, oxygen 1
4Vo1%, -nitrogen oxide 16■01ch and nitrogen 56V
16.71/hr of raw material mixed gas consisting of o1%,
251 methanol solution containing 60VO1'% 1,4-hexadiene! //Each velocity in hr (space velocity, 16
An experiment was conducted in the same manner as in Example 1, except that the water was supplied at a rate of 90/hr).

As a result, 5,5-dimethoxy-2-
Hexene was obtained with a space-time yield of 24 f/l-cat-hr.

Example 18 From the top of the reactor, oxygen 5 VO 1% + nitrogen 95 Vol
Mixed gas consisting of qlr at 17t/hr, 18■01e
The same procedure as that of Example 1 was used, except that an n-butanol solution containing lb1-hexene and 22Vo1% n-butyl nitrite was supplied at a rate of 50yxl/br (space velocity, 1950/hr), and the reaction temperature was 114°C. The experiment was conducted in the same manner as in 1.

As a result, 2,2-dibutoxyhexane was obtained as an acetal with a space-time yield of 35 f/1-cat-hr.

Example 19 A raw material mixed gas consisting of 17Vo1% ethanol, 14V01% oxygen, 18Vo1% -nitrogen oxide, 14Vo1% ethyl nitrite, and 1% Nitrogen 35V at 15.21%
/hr.

An ethanol solution containing 20 Vo1% ethyl crotonate was added at each rate of 40 ml/hr (space velocity + 1950/hr).
hr) and the reaction temperature was 125°C.

An experiment was conducted in the same manner as in Example 1.

As a result, β, β-jethoxy n-ethyl butyrate was obtained as an acetal with a space-time yield of 10 f/t-cat-hr.

Patent applicant: Ube Industries Co., Ltd. Continuation of page 1 0 shots clear person Takashi Umezu 5 U, 1978 Oaza Kogushi, Ube City Bukosan Co., Ltd. Central Research Laboratory

Claims (1)

[Claims] Olefins, alcohols and nitrites. (a) a platinum group metal or a salt thereof; and (b) A method for producing acetal characterized by contacting in a gas phase in the coexistence of an iron compound.