CA2193407A1 - Esterification of (meth)acrylic acid with an alkanol - Google Patents
Esterification of (meth)acrylic acid with an alkanolInfo
- Publication number
- CA2193407A1 CA2193407A1 CA002193407A CA2193407A CA2193407A1 CA 2193407 A1 CA2193407 A1 CA 2193407A1 CA 002193407 A CA002193407 A CA 002193407A CA 2193407 A CA2193407 A CA 2193407A CA 2193407 A1 CA2193407 A1 CA 2193407A1
- Authority
- CA
- Canada
- Prior art keywords
- meth
- acid
- acrylic acid
- bottom product
- weight
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 title claims abstract description 35
- 238000005886 esterification reaction Methods 0.000 title claims abstract description 26
- 230000032050 esterification Effects 0.000 title claims abstract description 25
- 238000000034 method Methods 0.000 claims abstract description 29
- -1 acrylic ester Chemical class 0.000 claims abstract description 22
- 239000003054 catalyst Substances 0.000 claims abstract description 16
- 239000003377 acid catalyst Substances 0.000 claims abstract description 9
- 238000004821 distillation Methods 0.000 claims abstract description 8
- 239000007858 starting material Substances 0.000 claims abstract description 7
- 238000010494 dissociation reaction Methods 0.000 claims description 24
- 230000005593 dissociations Effects 0.000 claims description 24
- 239000002253 acid Substances 0.000 claims description 23
- 239000000047 product Substances 0.000 claims description 23
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 16
- 150000007513 acids Chemical class 0.000 claims description 9
- 239000007789 gas Substances 0.000 claims description 7
- JOXIMZWYDAKGHI-UHFFFAOYSA-N toluene-4-sulfonic acid Chemical compound CC1=CC=C(S(O)(=O)=O)C=C1 JOXIMZWYDAKGHI-UHFFFAOYSA-N 0.000 claims description 4
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 3
- 229910001882 dioxygen Inorganic materials 0.000 claims description 3
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 3
- 239000011707 mineral Substances 0.000 claims description 3
- 150000007524 organic acids Chemical class 0.000 claims description 2
- 235000005985 organic acids Nutrition 0.000 claims description 2
- 206010013457 Dissociation Diseases 0.000 claims 2
- AFVFQIVMOAPDHO-UHFFFAOYSA-N Methanesulfonic acid Chemical compound CS(O)(=O)=O AFVFQIVMOAPDHO-UHFFFAOYSA-N 0.000 claims 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims 2
- 208000018459 dissociative disease Diseases 0.000 claims 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims 1
- 229940098779 methanesulfonic acid Drugs 0.000 claims 1
- 239000001301 oxygen Substances 0.000 claims 1
- 229910052760 oxygen Inorganic materials 0.000 claims 1
- 150000002148 esters Chemical class 0.000 description 17
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 14
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 13
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 8
- 150000002500 ions Chemical class 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 7
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 6
- 241000282320 Panthera leo Species 0.000 description 6
- CQEYYJKEWSMYFG-UHFFFAOYSA-N butyl acrylate Chemical compound CCCCOC(=O)C=C CQEYYJKEWSMYFG-UHFFFAOYSA-N 0.000 description 5
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 238000010626 work up procedure Methods 0.000 description 4
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 238000006845 Michael addition reaction Methods 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 125000000484 butyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- DURPTKYDGMDSBL-UHFFFAOYSA-N 1-butoxybutane Chemical compound CCCCOCCCC DURPTKYDGMDSBL-UHFFFAOYSA-N 0.000 description 2
- YIWUKEYIRIRTPP-UHFFFAOYSA-N 2-ethylhexan-1-ol Chemical compound CCCCC(CC)CO YIWUKEYIRIRTPP-UHFFFAOYSA-N 0.000 description 2
- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 150000001336 alkenes Chemical class 0.000 description 2
- 125000000217 alkyl group Chemical group 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 125000000383 tetramethylene group Chemical group [H]C([H])([*:1])C([H])([H])C([H])([H])C([H])([H])[*:2] 0.000 description 2
- MMNSHNBVSJFTNA-UHFFFAOYSA-N 1h-phosphole-2-carboxylic acid Chemical compound OC(=O)C1=CC=CP1 MMNSHNBVSJFTNA-UHFFFAOYSA-N 0.000 description 1
- ALRHLSYJTWAHJZ-UHFFFAOYSA-N 3-hydroxypropionic acid Chemical compound OCCC(O)=O ALRHLSYJTWAHJZ-UHFFFAOYSA-N 0.000 description 1
- 101150114464 ATRN gene Proteins 0.000 description 1
- 241000125205 Anethum Species 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 description 1
- 101150021395 JUND gene Proteins 0.000 description 1
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 description 1
- 241000153282 Theope Species 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 150000001252 acrylic acid derivatives Chemical class 0.000 description 1
- 230000001154 acute effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 125000003545 alkoxy group Chemical group 0.000 description 1
- 125000005907 alkyl ester group Chemical group 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- PYRZPBDTPRQYKG-UHFFFAOYSA-N cyclopentene-1-carboxylic acid Chemical compound OC(=O)C1=CCCC1 PYRZPBDTPRQYKG-UHFFFAOYSA-N 0.000 description 1
- 239000008130 destillate Substances 0.000 description 1
- 150000001983 dialkylethers Chemical class 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000011552 falling film Substances 0.000 description 1
- 229940085918 formadon Drugs 0.000 description 1
- ZZUFCTLCJUWOSV-UHFFFAOYSA-N furosemide Chemical compound C1=C(Cl)C(S(=O)(=O)N)=CC(C(O)=O)=C1NCC1=CC=CO1 ZZUFCTLCJUWOSV-UHFFFAOYSA-N 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- BDJSOPWXYLFTNW-UHFFFAOYSA-N methyl 3-methoxypropanoate Chemical compound COCCC(=O)OC BDJSOPWXYLFTNW-UHFFFAOYSA-N 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 210000003254 palate Anatomy 0.000 description 1
- PNJWIWWMYCMZRO-UHFFFAOYSA-N pent‐4‐en‐2‐one Natural products CC(=O)CC=C PNJWIWWMYCMZRO-UHFFFAOYSA-N 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 150000003460 sulfonic acids Chemical class 0.000 description 1
- 238000005809 transesterification reaction Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
- C07C69/52—Esters of acyclic unsaturated carboxylic acids having the esterified carboxyl group bound to an acyclic carbon atom
- C07C69/533—Monocarboxylic acid esters having only one carbon-to-carbon double bond
- C07C69/54—Acrylic acid esters; Methacrylic acid esters
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/08—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/60—Separation; Purification; Stabilisation; Use of additives by treatment giving rise to chemical modification
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C68/00—Preparation of esters of carbonic or haloformic acids
- C07C68/08—Purification; Separation; Stabilisation
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Abstract
In a process for esterifying (meth)acrylic acid with an alkanol in the presence of an esterification catalyst in which unreacted starting com-pounds and the (meth)acrylic ester formed are separated off by distillation and a bottom product containing oxy esters is obtained, the bottom product is separated off and either the bottom product is directly admixed with (meth)acrylic acid and the oxy esters present in the bottom product are then dissociated at an elevated temperature in the presence of acid catalysts different from (meth)acrylic acid, or the oxy esters are first separated by distillation from the bottom product, the distillate is admixed with (meth)acrylic acid and is then dissociated at an elevated temperature in the presence of acid catalysts different from (meth)acrylic acid.
Description
2193~07 .` 1 sEsteriflcation of (meth)acrylic acid with an aL~canol The invention relates to a process for the esterification of (meth)acrylic acid with an alkanol in the p-~sence of an est~ ~ification catalyst, in which ul~acl~d starting co,llpounds and the (meth)acrylic ester o formed are sepal.-t~ off by ~lictill~tion and a bottom product compLisillg oxy esters is oblaill~d. The term (meth)acrylic acid here denotes, as is ;u~tOludl~, acrylic or methacrylic acid.
The ~l~pdl~liOn of alkyl esters of (meth)acrylic acid is usually carried out by esterification of (meth)acrylic acid with alkanols at elevated IS lelllpclatul~ in the liquid phase in the pl~æ~ce or absellce of solvent and in the plesen~e of acid as catalyst (DE-A 23 39 519). A disad~an~ge of this method of pl~ar~lion is the second&~ acliol~ occulli,lg under the ab.,~_.l,cntiol~d esterification conditions, viz. as yet unreacted starting alcohol adds onto the double bond of alkyl (meth)acrylate already formed 20 (Michael addition) to give a coll~.Jund of the general formula I below an as yet u,~act~d (meth)acrylic acid adds onto the double bond of the ester formed to give a colllp~ulld of the general formula II. Multiple addition is also pGssible. In addition, mixed types can occur. These addl-c~c (alkoxy esters and acyloxy esters) are abbreviated as oxy esters.
R' RO--(CH2--CH--C02),~--R (I) R' R' 3SCH2 = C--CO2 --(CH2--CH --C02)y--R (II) 2193~07 where x,y = 1-5 R = alkyl R' = H or CH3 When R' = H, the esterification is of acrylic acid, when R' = CH3, the esterification is of ~ lic acid.
The problem of oxy ester fo~ ation is particularly acute in the preparation of esters of acrylic acid, with the main oxy esters formed being alkuAy~ropionic esters and acylox~l,rol~ionic esters where x,y = 1. In the preparation of esters of methacrylic acid, oxy ester follnalion occurs to a o lesær extent. The formation of oxy esters is de3clil~i in DE-A 23 39 529.
This indicates that the f~J~llldlio~ of oxy esters occurs es~-n;~lly ;.~rlepe-~-dently of the specific esterification co~ ;o!~ Of very particular in~ ce, is oxy ester formadon in the pl~alaliol of acrylates of Cl-C8-alkanols, in particular C4-C8-alkanols, very particularly in the pl~pal~iliOII of n-butyl acrylate and 2-ethylhe%yl acrylate.
It is a chala~tl.ist;c of the oxy esters that their boiling point is above the boiling point of starting acid, starting alcohol, target ester formed and any organic solvent also used.
The work-up of any such est~,ifcation reaction mi~lure is normally 20 carried out by, separadng unleact~ starting coml,uunds and the target este - from the reaction IlliA~, by disdlladon, with the acid catalyst used for the est~,.;fic~io.~ being able to be l~.llo~ befo.~halld, if appropriate, by extraction with water and/or aqueous , lkali (cf. for e,~alnple, Ullmann's Encyclopedia of In~llial Cl~.~i~,t~y, Vol. A1, 5th Ed., VCH, p. 167 ff.).
2s The bottom plul~lct re~nsini~ in such a ~ictillq~ive work-up c`ontains the o~y esters which result in a consid~.able loss in yield.
For this reason, various further ~ have been e-~-..in~d in order to solve the ploble~s res~ from follllalioll of the oxy esters.
Thus, JP-A-82/62229 desclibes the qllrqlinP sai~ullirlcation of the high-boiling30 esterification lesiducs. In this way, part of the alcohol used and acrylic acid and ~B-hydroxypropionic acid or their salts are recovered. A simple and econol,lical return of the products to the esterification reaction is therefore not possible. JP-B-72/15936 describes the pl~pa,dtion of acrylic esters by reacting ~B-alko,~,ylopionic esters with acrylic acid in the presellce of strong5 acids (transesterification). However, this forms as by-product equimolar ~ r~ i of ~B-alkuAy~lopionic acid which caMot be elu"led to the esterifi-cation l~a~lion and ll,e.efol., r~present waste material. JP-A-93/25086 des-cribes the dissocid~ion of the Michael addition product butyl ,B-l-lto.~yl~lopiollate (see formula I, x = 1, R = butyl) at cle~,at~d te"l~la-o ture and in the p~c3el~ce of sulfuric acid and an excess of water. However,the yield is ody about 30%. Finally, JP-A-94/65149 desclibes the ~ oc;~
tion of the Michael addition pl~h~;ts I and II (see above, x = y - 1) in the pl~e of lits~ .,, aiL~ ;des. In this reaction, the coll~lsio~ is likewise low ( < 60%) and large a noun~ of titanate are luces~ y. This 15 process is thel~fol~ ullecol~o.l~ l and ell~o~e.lt~lly ullfiielldly because of the large amounts of titanate to be dk.posed of.
GB 923 595 desclibes the .~co~ of llo~--.el~ from the residue of the esterification of acrylic acid with alkanols in the ab~e.~ce of molecu-lar o~ygen. It ~co..-~ c, inter alia, the removal of all volatile .llonu 20 prior to the d,issociation, tli~soc;~;on in the ple3encc of sulfuric acid and removal of the di~s~ n pr~luc~ by means of a stream of inert gas.
Accol-iing to the CA~IpleS, the dissociation is always carried out at at least 300C. Coke is formed as residue (17~0%) and this has to be dug out of the reactor. This process is ~ fol~ neither econonlical nor can it be 25 carried out on an h~l~stlial scale. A further disadvantage is the need to e..~lude o~ygen.
CN-A 1,063,678 dc3~,lil~s the ~k$~i~t;Q" of the aL~ ~iJnic ester present in the est~lir.calion residue in the pl~sencc of sulfuric acid in a cascade, with temperature and catalyst conc~,nlldtion (0.8-1.5%) being 30 ~ al in each reactor. Coupled with the dicc~;qliQn is a distillation to separate alkanol and acrylate. The process is very cumbersome and does not achieve high conversions.
Finally, CN-A 1,058,390 describes the dissociation of alkoxypropionic esters in the presence of sulfuric acid, etc., into alkanols and acrylic esters. This is carried out stepwise. The dissociation is first carried out under reflux and the reaction products are subsequently distilled off. The dissociation of the acrylic acid-containing ester residues from the preparation of ethyl/methyl acrylate (ethyl ethoxy-lo propionate, methyl methoxypropionate) is carried out in thepresence of ethanol or methanol. Here too, the process is complicated and does not achieve high conversions.
It is an object of the present invention to carry out the redissociation of the oxy esters present in this bottom product and to reuse the starting acid, starting alcohol and target ester obtained thereby for the purposes of the esterification without the disadvantages of the processes of the prior art.
We have found that this object is achieved by a 20 process for esterifying (meth)acrylic acid with an alkanol in the presence of an esterification catalyst in which unreacted starting compounds and the (meth)acrylic ester formed are separated off by distillation and a bottom product containing oxy ester is obtained, wherein the bottom product is separated off and either (a) the bottom product is admixed directly with (meth)acrylic acid and the oxy esters present in the bottom product are dissociated at an elevated temperature in the presence of acid catalysts different from (meth)acrylic acid, or (b) the oxy esters are first separated by distillation from 30 the bottom product, the distillate is admixed with (meth)acrylic acid and is dissociated at an elevated temperature in the presence of acid catalysts different from (meth)acrylic acid. The alkanol is preferably n-butanol or 2-ethylhexanol. In general, from 5 to 50% by weight, preferably from 10 to 40% by weight, based on amount of bottom product in (a) or distillate in (b), of (meth) acrylic acid is added.
2193~07 4a (Meth)acrylic acid is normally added in a form known per se, stabilized by means of polymerization inhibitors. According to an advantageous embodiment of the invention, the process of dissociation is carried out in the presence of molecular oxygen.
In contrast to dissociation without the addition of (meth)acrylic acid, the process according to the invention results in reduced formation of by-products (dialkyl ethers, olefins).
According to an advantageous devetopment of the invention, the 5 bottom product has added to it, in addition to the acid esterification catalyst which is di~.~lt from (meth)acrylic acid and may already be present, further acids select~d from the group concicl;ne of mineral acids such as sulfuric acid or phospholic acid, and alkyl- or arylsulfonic acids such as "~ v-.lfonic acid or p-tolue!l~sulfonic acid. The total amount of acids ~o dill;~nl from (meth)acrylic acid which is then present can be from 1 to 20% by weight, p~ ,ably from 5 to 15% by weight, based on the amount of the bottom product in (a) or destillate in (b). Co~ yonding catalytic acid contents are a~l~anlage~ s for the l~iss~ialioll if this is pl~ceded by sti~ ive separation of the oxy esters. It is particularly useful if a strip-5 ping gas preferably co.-~ ;ng molecular oxygen is pæsed lhlougll the bottom pl~lucl in (a), or tll~vugll the ~i~till~e in (b) oht~ ed ~l,el~,fio-ll, æ
an ellt~aiL~r for the dicsoci~;on pl~lU~;lS. Air or IllLl~Ui~,S of air with inert gæ (e.g. niLI-)gel~) are advantageously used as sl,ip~ g gas.
The advantages of the process of the present hl~.dioll are, in 20 particular, that the dissociation pl~lcecds more quickly, a smaller amount ofby-plu~l~cls such as ethers or olefins is formed and a smaller ~nollnt of acidic C~iRsoc;qt;on catalyst is co~ ...r~. Thus, among other things, smaller losses of starting materials, particularly of alcohols, occur than in known p~cesses. In a~dition~ high l1iC~ ion yields can be achieved. The direct 25 return of the I;cs~i~t;on llli,~l.n., does not adversely affect the purity of the (meth)aclylic ester and leads to a low ether content. For this reason, no coLu~licated separation of the ether from the easily polyl~ i~bl~
(meth)acrylic ester is ~esc-~y.
In the ~istill~ive sepalalion of the oxy esters from the bottom 30 p~ ct, the (1ictill~tion coL~dilions depend on the type of alcohol colll~
2193~7 ~.
.- 6 used in the esterification. In general, a temperanlre of from 100 to 300C
and a pressure of from I to 50 mbar are employed. Any conventional ~i~tillq~ion appdlalus is suitable for the ~i~till~ion process. Since only a simple 3CpalatiOII task is to be pe,~u~llled, a simple splash guard is gener-5 ally ~ jen~, i.e. a column is not normally le~luil~d.
For the work-up accol~lh~g to the present i"~enliol~ of the oxy esters ûbtained in the bottom pl~blcl in the esterification or of the oxy ester ~ tillqt~ separated from the esterification bollo~lls a simple heatable stirred reactor with jacket heating or heating coil, or else a forced-circula-lO tion evaporator, for example a falling-film evaporator or flash e~olatol, c~,u~ vith a ia;~1F~ e time vessel, can be used. To achieve better separation of the ~I;R~ ';OU p.ud~ from the bottom p.û.luct or oxy ester distillate, it may be advsn~sgeous to use a ~e~l;fi~a~ion ~ super-posed on the diwociation apparatus, for example a packed or tray column.
15 This recdficadon attachment is generally O~l..t~ using stabUization by polr~e.~ation inhibitu.~ (e.g. phellolhi-~, hydro~luh~ol~e mol~ol.,e~h,l etber, etc.).
The conditiol~s for c~.yi"g out the process ûf the present invention for dissociating oxy esters fonned in the bottom p.ol~cl in the esh,irl~lion 20 or sep~dt d f,rom the bottom p-c~-ct are as follows:
Catalyst: at least one acid selecte~ from the group consi-sting of mineral acids, for cA~plE sulfuric acid and phû~lJh~.ic acid, and organic acids different from (meth)acrylic acid, for example alkyl- or arylsulfonic acids such as ~ h~l-f;,.. ifonic or p-toluenesulfonic acid Amount of catalyst: 1-20% by weight, preferably 5-15% by weight, based on the ~mo~ln~ of boKom ploducl in (a) or on the amount of the oxy ester di~ti~ e s~pa,~t~d from the boKom p~ . l in (b) .
Amount of (meth)acrylic acid: 5-50% by weight, preferably 10-40% by weight, based on the arnount of bottom pluducl in (a) or on the arnount of the oxy ester lictillqte s~paldted from the bottom plOduCt in (b) Te.n~eldt~le: 150-250C, preferably 180-230C
~I~S~ule: preferably at atlllos~he.ic ple~ ~ or under l'educed pl~S~UI'~_ (SO that the dissociation pro-ducts i.. ~ tely vapvli~e) (< 1 atrn) o S~ipping gas, if used: ~qrnolln~ 1-10" I/h Reaction time: 1-10 hours CGn~ ion: 2 90%
The reaction is carried out, for eAhl~le, by the bottom IJ.udu~l 15 to be dissociated being taken CV.~ U~J$IY from the distilladve work-up of the e~t.i~cation l,~t~i~ and fed tog~ el with the dissociation catalyst to the dissociadon reactor. However, the reaction can also be carried out bat~h..ise. It is also possible to use a ~lllicvnlilluous lea~lion l~lvceJul~, in which the l"vdu~:l to be dissociat~d is cG~ v!~sly fed to the ~icsoc;qt;v 20 reactor (which. cu~ i.u the ~licsoci~;on catalyst), and the bottom p.oduct isle,nv.~d batchwise frvm the dissociation reactor ody after the dissociadon is complete. The dissociation plodu~:ts are ~palat~ off condnuously by distillation.
The applicabiliq of the ~ksoc;~lion prvcess de~lil~ is not 25 ~tli~t~d to a sp~cific qpe of e~tlillcativl process from which the oxy esters, i.e. the addition co~u~ds I and Il, are obt~ d as by-plvluc~.
In genetal~ the esters are plep&cd by c~-~t~""q~ i"-lh~s (see Ullmann's E.~;)clo~ia of Industrial Ch--n;st~, Vol. Al, 5th Ed., VCH, p. 167 ff.).
2193~07 A typical example of the conditions under which the esterification prece~ing the d6sociation of the oxy esters can take place can be briefly ~l~nt~d as follows:
Alcohol: (meth)acrylic acid 1:0.7-1.2 (molar) Catalyst: sulfuric acid or sulfonic acids Amount of catalyst: 0.1-10% by weight (p-~f~ bly 0.5-S%
by weight) based on starting material Stabilization: 200-2,000 ppm of phello~ based on the weight of the starting o materials) Reacdon temperature: 80-160C, preferably 90-130C
Reaction time: 1-10 hours, preferably 1-6 hours If desired, an e~llaill~[ (e.g. cycloh~a.K or toluene) may be used to remove the water of est~lific~tion. The e~t~lification can be carried out ~s at ato ~ .ic l,le~ , under ~u~ nû~,hr~ic ~ or subat,.~ospk--.;c ,S~, either co.~ ly or batchwise.
In the acid-catalyzed esterification of acrylic acid with aLkanols, the bottom p~ ;l obl~d aRer sepaldting off the acid esterification catalyst, the unreacted starting materials and the acrylic ester generally has the following,cû~ )os;t~on:
1-20% by weight of acrylic ester 50-80% by weight of al~o~l"opio~t~s (see formula I) 5-30% by weight of acyluA~ opiollates (æe formula II) remsi~er: mainly stabilizers (pheno~t.i~ -) and polymers 2S Further details and advantages of the pl~lcesS of the present ~ion may bc taken from the P~ p!r5 dc3elit~d bclow.
Pirstly, a result achieved using a process not acwld~g to the prcsent in~cntion will be des~;lil,cd by means of a COnlpdl:ali~_ c~ple.
COMPARATIVE EXAMPLE
_ g A glass circulation reactor (volume: I l) heated by means of a heating plug was charged with 500 g of an oxy ester ~ till~te obtained from an esterification residue from n-butyl acrylate production which has been freed of the acid esterification catalyst, togetl,er with 40 g of p-tolue-5 nesulfonic acid. The oxy ester distillate co"~,ised 11.0% by weight of butyl acrylate, 64.8% by weight of butoxy ester I ( R = C4H9) 20.5% by weight of acyloxy ester II ( R = C4H9).
The ~iCs~ on temperature was 195C and the ope~ling p~s~ e was 1 atm.
During the dissociation, the esterification residue to be dissociated was co.~ o~Qly fed to the dissociation reactor, regl~ls~.~d by the level in the reactor.
The dissociation ploducls were taken off in vapor form and 15 CO~ ~ at the top of the column (50 cm x 2.8 cm, empty) w~yO3ed on the dissociation reactor. Over a period of 119.5 hours, 7,401 g of - lniAt~, (62 g/h) were fed to the ~icsoci~ion reactor and 7,080 g of dissociation pivdu~;ls were con-1~ n5e~.
Accol~ing to analysis by gas chr~n~dtu~.alJhy, the cond~,~ate 20 C~
72.0% by weight of butyl acrylate 13.9% by weight of butanol 4.8% by weight of acrylic acid 1.4% by weight of dibutyl ether 6.6% by weight of butenes 0.2% by weight of butyl l,.~lu~ vpionate Co.~ ;on: 96% by weight based on o~cy esters.
The dissociation bollv~s were still readily handleable (pumpable) at 25C and co..~ rd no solids.
3~ EXAMPLE OF THE PROCESS OF THE PRESENT INVENTION
2193gO7 A glass circulation reactor (volume: I l) heated by means of a heating plug was charged with 500 g of the oxy ester di.c~ te from the Co",pal~tive E~ample, with addition of 40 g of p-toluenPsl~lfonic acid and 150 g of acrylic acid (stabilked with 300 ppm of phe~ h;~7i.~r,).
The dicsoci~;oll t~mpe.dtu.e was 195C and the o~.ating p.~v;,.~,~
was 1 atm.
The o~y ester distillate to be dissociated and the co.,~v~onding addilioll of acrylic acid (30% by weight) were continuously fed to the dissociation reactor, regl~ ~ by the level in the reactor. The ~ s~i~l;o I,.~hl~ts were condcnsed at the top of the column (S0 cm x 2.8 cm, empty) ;.upe.~os~ on the reactor.
Over a period of 118 hours, 12,323 g of oxy ester distillate (104 g/h) and 3,697 g of stabilked acrylic acid were fed to the dissociation reactor and lS,S29 g of l,.odu. t ~ , were conf1e~-~d. Accolding to 5 analysis by gas chromatography, the colU~e~ COI~li~:
67.3 % by weight of butyl acrylate S.3 % by weight of butanol 21.2% by weight of acrylic acid 0.4% by weight of dibutyl ether 2.3 % by weight of butenes Co-~ ;on: 97 % by weight, based on o~cy esters.
It can be seen from the above e~mple of the ~.~ess of the present il~nlion that this process is able to achieve higher co-l~e.sions and results in srnaller losses of starting material than in known p..Jcesses.
The ~l~pdl~liOn of alkyl esters of (meth)acrylic acid is usually carried out by esterification of (meth)acrylic acid with alkanols at elevated IS lelllpclatul~ in the liquid phase in the pl~æ~ce or absellce of solvent and in the plesen~e of acid as catalyst (DE-A 23 39 519). A disad~an~ge of this method of pl~ar~lion is the second&~ acliol~ occulli,lg under the ab.,~_.l,cntiol~d esterification conditions, viz. as yet unreacted starting alcohol adds onto the double bond of alkyl (meth)acrylate already formed 20 (Michael addition) to give a coll~.Jund of the general formula I below an as yet u,~act~d (meth)acrylic acid adds onto the double bond of the ester formed to give a colllp~ulld of the general formula II. Multiple addition is also pGssible. In addition, mixed types can occur. These addl-c~c (alkoxy esters and acyloxy esters) are abbreviated as oxy esters.
R' RO--(CH2--CH--C02),~--R (I) R' R' 3SCH2 = C--CO2 --(CH2--CH --C02)y--R (II) 2193~07 where x,y = 1-5 R = alkyl R' = H or CH3 When R' = H, the esterification is of acrylic acid, when R' = CH3, the esterification is of ~ lic acid.
The problem of oxy ester fo~ ation is particularly acute in the preparation of esters of acrylic acid, with the main oxy esters formed being alkuAy~ropionic esters and acylox~l,rol~ionic esters where x,y = 1. In the preparation of esters of methacrylic acid, oxy ester follnalion occurs to a o lesær extent. The formation of oxy esters is de3clil~i in DE-A 23 39 529.
This indicates that the f~J~llldlio~ of oxy esters occurs es~-n;~lly ;.~rlepe-~-dently of the specific esterification co~ ;o!~ Of very particular in~ ce, is oxy ester formadon in the pl~alaliol of acrylates of Cl-C8-alkanols, in particular C4-C8-alkanols, very particularly in the pl~pal~iliOII of n-butyl acrylate and 2-ethylhe%yl acrylate.
It is a chala~tl.ist;c of the oxy esters that their boiling point is above the boiling point of starting acid, starting alcohol, target ester formed and any organic solvent also used.
The work-up of any such est~,ifcation reaction mi~lure is normally 20 carried out by, separadng unleact~ starting coml,uunds and the target este - from the reaction IlliA~, by disdlladon, with the acid catalyst used for the est~,.;fic~io.~ being able to be l~.llo~ befo.~halld, if appropriate, by extraction with water and/or aqueous , lkali (cf. for e,~alnple, Ullmann's Encyclopedia of In~llial Cl~.~i~,t~y, Vol. A1, 5th Ed., VCH, p. 167 ff.).
2s The bottom plul~lct re~nsini~ in such a ~ictillq~ive work-up c`ontains the o~y esters which result in a consid~.able loss in yield.
For this reason, various further ~ have been e-~-..in~d in order to solve the ploble~s res~ from follllalioll of the oxy esters.
Thus, JP-A-82/62229 desclibes the qllrqlinP sai~ullirlcation of the high-boiling30 esterification lesiducs. In this way, part of the alcohol used and acrylic acid and ~B-hydroxypropionic acid or their salts are recovered. A simple and econol,lical return of the products to the esterification reaction is therefore not possible. JP-B-72/15936 describes the pl~pa,dtion of acrylic esters by reacting ~B-alko,~,ylopionic esters with acrylic acid in the presellce of strong5 acids (transesterification). However, this forms as by-product equimolar ~ r~ i of ~B-alkuAy~lopionic acid which caMot be elu"led to the esterifi-cation l~a~lion and ll,e.efol., r~present waste material. JP-A-93/25086 des-cribes the dissocid~ion of the Michael addition product butyl ,B-l-lto.~yl~lopiollate (see formula I, x = 1, R = butyl) at cle~,at~d te"l~la-o ture and in the p~c3el~ce of sulfuric acid and an excess of water. However,the yield is ody about 30%. Finally, JP-A-94/65149 desclibes the ~ oc;~
tion of the Michael addition pl~h~;ts I and II (see above, x = y - 1) in the pl~e of lits~ .,, aiL~ ;des. In this reaction, the coll~lsio~ is likewise low ( < 60%) and large a noun~ of titanate are luces~ y. This 15 process is thel~fol~ ullecol~o.l~ l and ell~o~e.lt~lly ullfiielldly because of the large amounts of titanate to be dk.posed of.
GB 923 595 desclibes the .~co~ of llo~--.el~ from the residue of the esterification of acrylic acid with alkanols in the ab~e.~ce of molecu-lar o~ygen. It ~co..-~ c, inter alia, the removal of all volatile .llonu 20 prior to the d,issociation, tli~soc;~;on in the ple3encc of sulfuric acid and removal of the di~s~ n pr~luc~ by means of a stream of inert gas.
Accol-iing to the CA~IpleS, the dissociation is always carried out at at least 300C. Coke is formed as residue (17~0%) and this has to be dug out of the reactor. This process is ~ fol~ neither econonlical nor can it be 25 carried out on an h~l~stlial scale. A further disadvantage is the need to e..~lude o~ygen.
CN-A 1,063,678 dc3~,lil~s the ~k$~i~t;Q" of the aL~ ~iJnic ester present in the est~lir.calion residue in the pl~sencc of sulfuric acid in a cascade, with temperature and catalyst conc~,nlldtion (0.8-1.5%) being 30 ~ al in each reactor. Coupled with the dicc~;qliQn is a distillation to separate alkanol and acrylate. The process is very cumbersome and does not achieve high conversions.
Finally, CN-A 1,058,390 describes the dissociation of alkoxypropionic esters in the presence of sulfuric acid, etc., into alkanols and acrylic esters. This is carried out stepwise. The dissociation is first carried out under reflux and the reaction products are subsequently distilled off. The dissociation of the acrylic acid-containing ester residues from the preparation of ethyl/methyl acrylate (ethyl ethoxy-lo propionate, methyl methoxypropionate) is carried out in thepresence of ethanol or methanol. Here too, the process is complicated and does not achieve high conversions.
It is an object of the present invention to carry out the redissociation of the oxy esters present in this bottom product and to reuse the starting acid, starting alcohol and target ester obtained thereby for the purposes of the esterification without the disadvantages of the processes of the prior art.
We have found that this object is achieved by a 20 process for esterifying (meth)acrylic acid with an alkanol in the presence of an esterification catalyst in which unreacted starting compounds and the (meth)acrylic ester formed are separated off by distillation and a bottom product containing oxy ester is obtained, wherein the bottom product is separated off and either (a) the bottom product is admixed directly with (meth)acrylic acid and the oxy esters present in the bottom product are dissociated at an elevated temperature in the presence of acid catalysts different from (meth)acrylic acid, or (b) the oxy esters are first separated by distillation from 30 the bottom product, the distillate is admixed with (meth)acrylic acid and is dissociated at an elevated temperature in the presence of acid catalysts different from (meth)acrylic acid. The alkanol is preferably n-butanol or 2-ethylhexanol. In general, from 5 to 50% by weight, preferably from 10 to 40% by weight, based on amount of bottom product in (a) or distillate in (b), of (meth) acrylic acid is added.
2193~07 4a (Meth)acrylic acid is normally added in a form known per se, stabilized by means of polymerization inhibitors. According to an advantageous embodiment of the invention, the process of dissociation is carried out in the presence of molecular oxygen.
In contrast to dissociation without the addition of (meth)acrylic acid, the process according to the invention results in reduced formation of by-products (dialkyl ethers, olefins).
According to an advantageous devetopment of the invention, the 5 bottom product has added to it, in addition to the acid esterification catalyst which is di~.~lt from (meth)acrylic acid and may already be present, further acids select~d from the group concicl;ne of mineral acids such as sulfuric acid or phospholic acid, and alkyl- or arylsulfonic acids such as "~ v-.lfonic acid or p-tolue!l~sulfonic acid. The total amount of acids ~o dill;~nl from (meth)acrylic acid which is then present can be from 1 to 20% by weight, p~ ,ably from 5 to 15% by weight, based on the amount of the bottom product in (a) or destillate in (b). Co~ yonding catalytic acid contents are a~l~anlage~ s for the l~iss~ialioll if this is pl~ceded by sti~ ive separation of the oxy esters. It is particularly useful if a strip-5 ping gas preferably co.-~ ;ng molecular oxygen is pæsed lhlougll the bottom pl~lucl in (a), or tll~vugll the ~i~till~e in (b) oht~ ed ~l,el~,fio-ll, æ
an ellt~aiL~r for the dicsoci~;on pl~lU~;lS. Air or IllLl~Ui~,S of air with inert gæ (e.g. niLI-)gel~) are advantageously used as sl,ip~ g gas.
The advantages of the process of the present hl~.dioll are, in 20 particular, that the dissociation pl~lcecds more quickly, a smaller amount ofby-plu~l~cls such as ethers or olefins is formed and a smaller ~nollnt of acidic C~iRsoc;qt;on catalyst is co~ ...r~. Thus, among other things, smaller losses of starting materials, particularly of alcohols, occur than in known p~cesses. In a~dition~ high l1iC~ ion yields can be achieved. The direct 25 return of the I;cs~i~t;on llli,~l.n., does not adversely affect the purity of the (meth)aclylic ester and leads to a low ether content. For this reason, no coLu~licated separation of the ether from the easily polyl~ i~bl~
(meth)acrylic ester is ~esc-~y.
In the ~istill~ive sepalalion of the oxy esters from the bottom 30 p~ ct, the (1ictill~tion coL~dilions depend on the type of alcohol colll~
2193~7 ~.
.- 6 used in the esterification. In general, a temperanlre of from 100 to 300C
and a pressure of from I to 50 mbar are employed. Any conventional ~i~tillq~ion appdlalus is suitable for the ~i~till~ion process. Since only a simple 3CpalatiOII task is to be pe,~u~llled, a simple splash guard is gener-5 ally ~ jen~, i.e. a column is not normally le~luil~d.
For the work-up accol~lh~g to the present i"~enliol~ of the oxy esters ûbtained in the bottom pl~blcl in the esterification or of the oxy ester ~ tillqt~ separated from the esterification bollo~lls a simple heatable stirred reactor with jacket heating or heating coil, or else a forced-circula-lO tion evaporator, for example a falling-film evaporator or flash e~olatol, c~,u~ vith a ia;~1F~ e time vessel, can be used. To achieve better separation of the ~I;R~ ';OU p.ud~ from the bottom p.û.luct or oxy ester distillate, it may be advsn~sgeous to use a ~e~l;fi~a~ion ~ super-posed on the diwociation apparatus, for example a packed or tray column.
15 This recdficadon attachment is generally O~l..t~ using stabUization by polr~e.~ation inhibitu.~ (e.g. phellolhi-~, hydro~luh~ol~e mol~ol.,e~h,l etber, etc.).
The conditiol~s for c~.yi"g out the process ûf the present invention for dissociating oxy esters fonned in the bottom p.ol~cl in the esh,irl~lion 20 or sep~dt d f,rom the bottom p-c~-ct are as follows:
Catalyst: at least one acid selecte~ from the group consi-sting of mineral acids, for cA~plE sulfuric acid and phû~lJh~.ic acid, and organic acids different from (meth)acrylic acid, for example alkyl- or arylsulfonic acids such as ~ h~l-f;,.. ifonic or p-toluenesulfonic acid Amount of catalyst: 1-20% by weight, preferably 5-15% by weight, based on the ~mo~ln~ of boKom ploducl in (a) or on the amount of the oxy ester di~ti~ e s~pa,~t~d from the boKom p~ . l in (b) .
Amount of (meth)acrylic acid: 5-50% by weight, preferably 10-40% by weight, based on the arnount of bottom pluducl in (a) or on the arnount of the oxy ester lictillqte s~paldted from the bottom plOduCt in (b) Te.n~eldt~le: 150-250C, preferably 180-230C
~I~S~ule: preferably at atlllos~he.ic ple~ ~ or under l'educed pl~S~UI'~_ (SO that the dissociation pro-ducts i.. ~ tely vapvli~e) (< 1 atrn) o S~ipping gas, if used: ~qrnolln~ 1-10" I/h Reaction time: 1-10 hours CGn~ ion: 2 90%
The reaction is carried out, for eAhl~le, by the bottom IJ.udu~l 15 to be dissociated being taken CV.~ U~J$IY from the distilladve work-up of the e~t.i~cation l,~t~i~ and fed tog~ el with the dissociation catalyst to the dissociadon reactor. However, the reaction can also be carried out bat~h..ise. It is also possible to use a ~lllicvnlilluous lea~lion l~lvceJul~, in which the l"vdu~:l to be dissociat~d is cG~ v!~sly fed to the ~icsoc;qt;v 20 reactor (which. cu~ i.u the ~licsoci~;on catalyst), and the bottom p.oduct isle,nv.~d batchwise frvm the dissociation reactor ody after the dissociadon is complete. The dissociation plodu~:ts are ~palat~ off condnuously by distillation.
The applicabiliq of the ~ksoc;~lion prvcess de~lil~ is not 25 ~tli~t~d to a sp~cific qpe of e~tlillcativl process from which the oxy esters, i.e. the addition co~u~ds I and Il, are obt~ d as by-plvluc~.
In genetal~ the esters are plep&cd by c~-~t~""q~ i"-lh~s (see Ullmann's E.~;)clo~ia of Industrial Ch--n;st~, Vol. Al, 5th Ed., VCH, p. 167 ff.).
2193~07 A typical example of the conditions under which the esterification prece~ing the d6sociation of the oxy esters can take place can be briefly ~l~nt~d as follows:
Alcohol: (meth)acrylic acid 1:0.7-1.2 (molar) Catalyst: sulfuric acid or sulfonic acids Amount of catalyst: 0.1-10% by weight (p-~f~ bly 0.5-S%
by weight) based on starting material Stabilization: 200-2,000 ppm of phello~ based on the weight of the starting o materials) Reacdon temperature: 80-160C, preferably 90-130C
Reaction time: 1-10 hours, preferably 1-6 hours If desired, an e~llaill~[ (e.g. cycloh~a.K or toluene) may be used to remove the water of est~lific~tion. The e~t~lification can be carried out ~s at ato ~ .ic l,le~ , under ~u~ nû~,hr~ic ~ or subat,.~ospk--.;c ,S~, either co.~ ly or batchwise.
In the acid-catalyzed esterification of acrylic acid with aLkanols, the bottom p~ ;l obl~d aRer sepaldting off the acid esterification catalyst, the unreacted starting materials and the acrylic ester generally has the following,cû~ )os;t~on:
1-20% by weight of acrylic ester 50-80% by weight of al~o~l"opio~t~s (see formula I) 5-30% by weight of acyluA~ opiollates (æe formula II) remsi~er: mainly stabilizers (pheno~t.i~ -) and polymers 2S Further details and advantages of the pl~lcesS of the present ~ion may bc taken from the P~ p!r5 dc3elit~d bclow.
Pirstly, a result achieved using a process not acwld~g to the prcsent in~cntion will be des~;lil,cd by means of a COnlpdl:ali~_ c~ple.
COMPARATIVE EXAMPLE
_ g A glass circulation reactor (volume: I l) heated by means of a heating plug was charged with 500 g of an oxy ester ~ till~te obtained from an esterification residue from n-butyl acrylate production which has been freed of the acid esterification catalyst, togetl,er with 40 g of p-tolue-5 nesulfonic acid. The oxy ester distillate co"~,ised 11.0% by weight of butyl acrylate, 64.8% by weight of butoxy ester I ( R = C4H9) 20.5% by weight of acyloxy ester II ( R = C4H9).
The ~iCs~ on temperature was 195C and the ope~ling p~s~ e was 1 atm.
During the dissociation, the esterification residue to be dissociated was co.~ o~Qly fed to the dissociation reactor, regl~ls~.~d by the level in the reactor.
The dissociation ploducls were taken off in vapor form and 15 CO~ ~ at the top of the column (50 cm x 2.8 cm, empty) w~yO3ed on the dissociation reactor. Over a period of 119.5 hours, 7,401 g of - lniAt~, (62 g/h) were fed to the ~icsoci~ion reactor and 7,080 g of dissociation pivdu~;ls were con-1~ n5e~.
Accol~ing to analysis by gas chr~n~dtu~.alJhy, the cond~,~ate 20 C~
72.0% by weight of butyl acrylate 13.9% by weight of butanol 4.8% by weight of acrylic acid 1.4% by weight of dibutyl ether 6.6% by weight of butenes 0.2% by weight of butyl l,.~lu~ vpionate Co.~ ;on: 96% by weight based on o~cy esters.
The dissociation bollv~s were still readily handleable (pumpable) at 25C and co..~ rd no solids.
3~ EXAMPLE OF THE PROCESS OF THE PRESENT INVENTION
2193gO7 A glass circulation reactor (volume: I l) heated by means of a heating plug was charged with 500 g of the oxy ester di.c~ te from the Co",pal~tive E~ample, with addition of 40 g of p-toluenPsl~lfonic acid and 150 g of acrylic acid (stabilked with 300 ppm of phe~ h;~7i.~r,).
The dicsoci~;oll t~mpe.dtu.e was 195C and the o~.ating p.~v;,.~,~
was 1 atm.
The o~y ester distillate to be dissociated and the co.,~v~onding addilioll of acrylic acid (30% by weight) were continuously fed to the dissociation reactor, regl~ ~ by the level in the reactor. The ~ s~i~l;o I,.~hl~ts were condcnsed at the top of the column (S0 cm x 2.8 cm, empty) ;.upe.~os~ on the reactor.
Over a period of 118 hours, 12,323 g of oxy ester distillate (104 g/h) and 3,697 g of stabilked acrylic acid were fed to the dissociation reactor and lS,S29 g of l,.odu. t ~ , were conf1e~-~d. Accolding to 5 analysis by gas chromatography, the colU~e~ COI~li~:
67.3 % by weight of butyl acrylate S.3 % by weight of butanol 21.2% by weight of acrylic acid 0.4% by weight of dibutyl ether 2.3 % by weight of butenes Co-~ ;on: 97 % by weight, based on o~cy esters.
It can be seen from the above e~mple of the ~.~ess of the present il~nlion that this process is able to achieve higher co-l~e.sions and results in srnaller losses of starting material than in known p..Jcesses.
Claims (10)
1. A process for esterifying (meth)acrylic acid with an alkanol in the presence of an esterification catalyst in which unreacted starting compounds and the (meth)acrylic ester formed are separated off by distillation and a bottom product containing oxy esters is obtained, wherein the bottom pro-duct is separated off and either (a) the bottom product is admixed directly with (meth)acrylic acid and the oxy esters present in the bottom product are dissociated at an elevated temperature in the presence of acid catalysts different from (meth)acrylic acid or (b) the oxy esters are first separated by distillation from the bottom pro-duct, the distillate is admixed with (meth)acrylic acid and is dissociated at an elevated temperature in the presence of acid catalysts different from (meth)acrylic acid.
2. A process as claimed in claim 1, wherein the amount of (meth)acrylic acid added is from 5 to 50% by weight, preferably from 10 to 40% by weight, based on the amount of bottom product in (a) or distillate in (b).
3. A process as claimed in claim 1, wherein the process of dissocia-tion is carried out in the presence of molecular oxygen.
4. A process as claimed in claim 1, wherein the dissociation is carried out at from 150 to 250°C, preferably from 180 to 230°C.
5. A process as claimed in claim 1, wherein the acid catalyst added is an acid selected from the group consisting of mineral acids such as sulfuric acid or phosphoric acid, and organic acids different from (meth)acrylic acid, for example alkyl- or arylsulfonic acids such as methane-sulfonic acid or p-toluenesulfonic acid.
6. A process as claimed in claim 5, wherein the added amount of acid catalyst different from (meth)acrylic acid is from 1 to 20% by weight, preferably from 5 to 15% by weight, based on the amount of bottom product in (a) or distillate in (b).
7. A process as claimed in claim 1, wherein the dissociation is carried out under reduced pressure (< 1 atm).
8. A process as claimed in claim 1, wherein a stripping gas is passed through the bottom product in (a) or distillate in (b) in order to remove the dissociation products.
9. A process as claimed in claim 8, wherein the stripping gas used is an oxygen-containing gas.
10. A process as claimed in any of claim 1 to 9, wherein the dis-sociation products obtained are returned directly to the esterification.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19547459A DE19547459A1 (en) | 1995-12-19 | 1995-12-19 | Esterifying (meth)acrylic acid with alkanol in presence of esterification catalyst |
| DE19547459.7 | 1995-12-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2193407A1 true CA2193407A1 (en) | 1997-06-20 |
Family
ID=7780580
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002193407A Abandoned CA2193407A1 (en) | 1995-12-19 | 1996-12-18 | Esterification of (meth)acrylic acid with an alkanol |
Country Status (13)
| Country | Link |
|---|---|
| EP (1) | EP0780360B1 (en) |
| JP (1) | JP4092740B2 (en) |
| KR (1) | KR100452078B1 (en) |
| CN (1) | CN1095826C (en) |
| BR (1) | BR9703406A (en) |
| CA (1) | CA2193407A1 (en) |
| CZ (1) | CZ369196A3 (en) |
| DE (2) | DE19547459A1 (en) |
| DK (1) | DK0780360T3 (en) |
| ES (1) | ES2145372T3 (en) |
| MX (1) | MX9606244A (en) |
| MY (1) | MY125609A (en) |
| SG (1) | SG79930A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR3008971A1 (en) * | 2013-07-29 | 2015-01-30 | Arkema France | PROCESS FOR THE CONTINUOUS PRODUCTION OF LIGHT ACRYLATES BY ESTERIFICATION OF A RAW ESTER ACRYLIC ACID |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19701737A1 (en) * | 1997-01-20 | 1998-07-23 | Basf Ag | Process for the esterification of (meth) acrylic acid with an alkanol |
| MY120051A (en) | 1997-07-30 | 2005-08-30 | Mitsubishi Rayon Co | Process for purification of (meth)acrylic acid |
| DE19922722A1 (en) | 1999-05-18 | 2000-11-23 | Basf Ag | Process for the preparation of (meth) acrylic acid esters |
| DE10127941A1 (en) | 2001-06-08 | 2002-05-29 | Basf Ag | Production of (meth)acrylate esters by transesterification comprises recycling by-product alcohol to the production of the starting (meth)acrylate |
| CN1240662C (en) | 2001-12-04 | 2006-02-08 | 三菱化学株式会社 | Process for producing (meth)acrylic acid compound |
| WO2005007609A1 (en) | 2003-07-11 | 2005-01-27 | Basf Aktiengesellschaft | Thermal separation method for separating at least one (meth)acrylmonomer-enriched material flow |
| DE102008054587A1 (en) | 2008-12-12 | 2010-06-17 | Basf Se | Process for the cleavage of Michael adducts contained in a liquid F, which was formed during the production of acrylic acid or its esters |
| WO2021224044A1 (en) | 2020-05-04 | 2021-11-11 | Basf Se | Method for breaking down michael adducts contained in a fluid f and formed during the preparation of acrylic acid |
| EP4015498B1 (en) | 2020-12-18 | 2024-04-24 | Basf Se | Method for the continuous production of acrylic acid n-butylester |
| WO2024149779A1 (en) | 2023-01-11 | 2024-07-18 | Evonik Operations Gmbh | Macromonomer and solid-state polymer electrolyte |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB923595A (en) | 1960-12-03 | 1963-04-18 | Distillers Co Yeast Ltd | Improvements in and relating to the production of acrylic esters |
| US3868410A (en) * | 1972-08-03 | 1975-02-25 | Celanese Corp | Conversion of oligomeric acrylates to acrylate monomers |
| DE2339529A1 (en) | 1973-08-03 | 1975-02-13 | Ardie Werk Gmbh | Accelerator linkage for heavy vehicle with fuel injection pump - has hydraulic servo to alter linkage length when changing gear |
| JPS5762229A (en) | 1980-10-02 | 1982-04-15 | Mitsubishi Petrochem Co Ltd | Recovery of useful component from heavy substance obtained as by-product in preparation of acrylic ester |
| CN1058390A (en) | 1990-07-13 | 1992-02-05 | 梁效成 | The treatment process of waste liquid containing alkoxyl propionic ester |
| JPH0768168B2 (en) | 1991-07-12 | 1995-07-26 | 東亞合成株式会社 | Decomposition method of Michael adduct of acrylic acid ester |
| CN1026104C (en) | 1992-03-17 | 1994-10-05 | 侯玉里 | Waste acrylate oil regeneration process |
| JP2943523B2 (en) | 1992-08-12 | 1999-08-30 | 東亞合成株式会社 | Method for producing useful compound from Michael adduct of acrylic acid ester |
-
1995
- 1995-12-19 DE DE19547459A patent/DE19547459A1/en not_active Withdrawn
-
1996
- 1996-12-09 MX MX9606244A patent/MX9606244A/en unknown
- 1996-12-10 MY MYPI96005184A patent/MY125609A/en unknown
- 1996-12-13 DE DE59605039T patent/DE59605039D1/en not_active Expired - Lifetime
- 1996-12-13 ES ES96120076T patent/ES2145372T3/en not_active Expired - Lifetime
- 1996-12-13 DK DK96120076T patent/DK0780360T3/en active
- 1996-12-13 EP EP96120076A patent/EP0780360B1/en not_active Expired - Lifetime
- 1996-12-16 CZ CZ963691A patent/CZ369196A3/en unknown
- 1996-12-17 JP JP33697796A patent/JP4092740B2/en not_active Expired - Lifetime
- 1996-12-18 KR KR1019960067282A patent/KR100452078B1/en not_active IP Right Cessation
- 1996-12-18 SG SG9611800A patent/SG79930A1/en unknown
- 1996-12-18 CN CN96121568A patent/CN1095826C/en not_active Expired - Lifetime
- 1996-12-18 CA CA002193407A patent/CA2193407A1/en not_active Abandoned
-
1997
- 1997-05-27 BR BR9703406A patent/BR9703406A/en not_active IP Right Cessation
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR3008971A1 (en) * | 2013-07-29 | 2015-01-30 | Arkema France | PROCESS FOR THE CONTINUOUS PRODUCTION OF LIGHT ACRYLATES BY ESTERIFICATION OF A RAW ESTER ACRYLIC ACID |
| WO2015015100A1 (en) * | 2013-07-29 | 2015-02-05 | Arkema France | Method for continuous production of light acrylates by esterification of a raw ester-grade acrylic acid |
| US20160159725A1 (en) * | 2013-07-29 | 2016-06-09 | Arkema France | Method for continuous production of light acrylates by esterification of a raw ester-grade acrylic acid |
| US9796651B2 (en) * | 2013-07-29 | 2017-10-24 | Arkema France | Method for continuous production of light acrylates by esterification of a raw ester-grade acrylic acid |
Also Published As
| Publication number | Publication date |
|---|---|
| JP4092740B2 (en) | 2008-05-28 |
| CZ369196A3 (en) | 1997-06-11 |
| BR9703406A (en) | 1999-01-05 |
| EP0780360B1 (en) | 2000-04-26 |
| ES2145372T3 (en) | 2000-07-01 |
| DE59605039D1 (en) | 2000-05-31 |
| KR970042476A (en) | 1997-07-24 |
| DK0780360T3 (en) | 2000-08-07 |
| KR100452078B1 (en) | 2004-11-16 |
| CN1095826C (en) | 2002-12-11 |
| MX9606244A (en) | 1998-04-30 |
| JPH09183753A (en) | 1997-07-15 |
| EP0780360A1 (en) | 1997-06-25 |
| DE19547459A1 (en) | 1996-07-25 |
| CN1158840A (en) | 1997-09-10 |
| MY125609A (en) | 2006-08-30 |
| SG79930A1 (en) | 2001-04-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |