CA2240196C - Process for the preparation of (meth)acrylic acid esters - Google Patents

Abstract

A process for the production of (meth)acryl esters of the Formula I See Formula I in which R1 stands for hydrogen or a methyl group and A and B stand for unbranched or branched alkylene groups with 2 to 5 C atoms. The process comprises the step of reacting an acrylic acid ester or methacrylic acid ester of Formula II See Formula II in which R1 is as defined above and R2 stands for an alkyl radical with 1 to 4 C atoms, with a heterocyclic compound of the Formula III in a reaction mixture See Formula III wherein A and B are as defined above. The process is carried out in the presence of a catalyst system comprising calcium hydroxide, wherein the catalyst system is present in the reaction mixture in an amount of 1 ppm to 250 ppm.

Description

PROCESS FOR THE PRODUCTION OF (METH)ACRYLIC ACID ESTERS
SPECIFICATION
Field of the Invention The present invention relates to a new and improved process for the production of acrylic or methacrylic acid esters with the formula R~ 0 B
.. , \
HZC= C - C-O-A-N NH
I
O
in which R, stands for hydrogen or a methyl group and A and B stand for unbranched or branched alkylene groups with 2 to 5 C atoms.
State of the Art Compounds of Formula I can be obtained in accordance with the process described in the U.S. patent 2,871,223, by means of reaction of acrylic or methacrylic acid chloride with hydroxyalkyl imidazolidine-2-ones in the presence of tertiary nitrogen bases, with stoichiometric amounts of the hydrochlorides of the tertiary nitrogen bases being formed, along with other products.

tn the process known from EP 0 236 984 A1, for the production of acryl and methacryt esters of Formula t, acrylic or methacrytic acid esters are rearfed with 1-(hydroxyaitcyl}
imidazotidine-2-ones in the presence of titanium atcohotates or chelafe compounds of the metals titanium, zirconium, iron, and zinc, with l,3-dicarbonyt compounds as the re-esterification catalysts.
In EP-A 0 433 'f 35 and EP-AO 453 638, diorgano tin oxide compounds are claimed ~as re-ester~cation catalysts for the re-esteTrfcation of acryl and methacryt esters with hydroxyattcyl imiciazotine-2-ones.
As a rule, the metal catalyst must be removed from batches after the reaction is complete. This is advantageously done by adding crater, fQr example when using tetraalkyl titanates yr diatkyt tin oxides. tn this eonriection, the titanates form metal (hydr}oxides, such as Ti02; vsihich are removed by filtering or centrifuging them off, for example_ These hydwolyzed re-esfeirftcation Catalysts cannot be used again as such after being removed.
It is true that the dialkyt tin oxides can be removed as such by the addition of wafer, and can be used again as re-esterification catalysts. However, a relatively large amount of water has to be introduced, at first, and this has to be removed from the reaction product once again. According to the European patent No.
0 571 851, the reaction can also be carried out in the presence of mixtures of alkaiilearth alkali metal compounds, which are essentially used as oxides, hydroxides, carbonates, andlor as salts of carboxylic aEids. The ~afkati/earth alkali compounds present as catalysts can be removed without adding water. The amount of catatyticalty active compound mixtures is 0.01 10 wt.-%, with reference to the reaction mixture. In spite of the advantageously high reaction speed which is achieved with alkaGlearth alkali catalysts, these systems stagnate after approximately 80% hydroxyalkyl imidazotidine-2-one conversion, so that the residual alcohol content in the reaction mixture is relatively high.

VY0 9T12?592 g I'CTIDE951a2i6t Also, the formation of N-(methacryloy) oxyefhyl)-N'-(rnetha~ryloyij ethylene urea, a bifunctiona! methacryt compound, which therefore has a cn~ss-linking effect during polymerization reactions, is very high, at approximately 't0°r'o' of the re-esterifi~ation compounds, aced must be irrzproved-to be at tower proportions.
_DE-t)S 3x13927 BASF) describes a polymer-anafog reaction with approximately 't00,000 ppm calcium hydroxide a5 the catalyst:
DE 2238208 describes the re-esterifcaf~on of bactericide quinoxaline derivatives with eaiciurr~ hydroxide or barium hydroxide catalysis.
SumrTaary of the Invention the invention relates to a process for the production of (meth)acty! esters of the formula I
R~s O Bt.
G= C _ C_p_a_N NH
!.
C
b in which R, stands for hydrogen or a methyl group and A and B stand fir unbranched or branched alkylene groups with 2 to ~ C atari~s, by reac~ian of an acr~Eic acid ester or methacrytic acid ester of Formula i1 p H2C= C _ C_O_Rz 1t, in vrihich Rj is as defined above and R~ stands for an alkyl iradicai v~h'1 to d'C, atoms, with ~a heterocyciic compound of .the Formula Ill . ' B ~, .
a . HO - A - H NH.
. . ~ ~ . . rig.
. .

wherein A and B are, as defined above, which is characterized by the fact that the.
reaction of an ester in accordance.with Formuia~ it vfn'th a h~cyclic ct~mpownd~~of ~Formute.lil is carfied out to pn~duce~.an acryl or xnethacrtrl est~t~of Formula I in the presence of a catalyst system comprising calcium hydroxide.
The invention was based on the task of finding a catalytic process for the pr4duc~fon of acrylic or methacryiic acid esters of i=armula ~I by alcoholysis of (n9eth)adcylic:at~d~ alkyl esters with'h~dr~xyalkyi irr~idaznlidine-~-pneg, which proceeds at a good, reac~i~n speead even in tfxe region of final re-esterificatiori, end in which the catalyst used can ~b~
removed from. the reaction mixture vu4thout adding irvsiter and ~ used again -as such, 'if necessary. It was now found thvt the reaction can be carried out ~in surprisingly advantageous manner with~cait~um hydroxidie, in an amount of lees than .250 p~pm, with referewce ~to the' tofal amount of the feactiort mixture:
yA particu[ar advantage of the new process is. thbt high rates of cx~eigiQn are:gchieved, ahd that tile catalyst.system which contains c~lciuii~.. which ie s~utrii~d'up quanttiveiy:
~ ~ ~ Y
to a. grt~af ant, irr the reaction rni~cture.~~ui ~be rer#wved witt~oWt.adding.~Wrtwe added 7.~, for exafnpie by frltration. Tcl,.~ is used as an aid for removing.
diss~oived catalyst (saaaptier: S~rdchemie MG).
Cornpvunds of~~omnula I are valuable corr~onome(s and are used, for exari~ple, ~in the production of polymer dispersions ,from vinyl monomers, which are prrmartly used as binders. in paints, for example, or as~leathor processing aids:, Cor~ionomer~s of * trade~narJc Wf3 97122582 5 ~F'GTtDE9gf021.69 Formula t impart a desired hydrophilic to copolymerizates, and can function as formaldehyde scavengers in heat-curable resins with their irrride group.
The success of the process according to the invention is surprising, since NH
grouping of a compound of Formula Itl,vsras to be expected in the presence of the catalyst, because of the bifunctionalities of t and l11, during their reaction In further reactions, such as addition reactions analogous to a Nfichae! addition to the double bond, or in amide formation by reaction of the acryl or methacryt ester of IFormuta t_ The. readtion of acryl and methacryl esters of Formula ti with the alcohots cif Forri~uta !1l, according to the invention, proceeds very se3ectivety to produce compounds of Formula t:
According to the process according to the invention, process products of Forrrlula E ate obtained, vsrhich can be used without costly and quatitattvety burdensome remova) prQCesses, directly, for example as a solution in the acryt or methacryl ester ft; for use as comonorr~ers, particularly in the production of dispersion polyrnerizates.
Compounds 1 can also be produced as solids according to the present press; for example by being evaporated from solution.
~ettteti ties~ription t~f the Preferred Embodiments of the Invention For production of the compounds 1 in accordance with the process acxording to the - inventipn, acrylic or methacrytic acid esters of Forrrt~la it ire used, iri ~rvhidh ~;2 particularly stands for an alkyl radical with 'I to 4 carbon a#oms. .As exampi~s, propyl acrytater, n-butyl acrytate, ethyl methacrytate, i-pwopyl methacrylate; i-btjtyl methacrytate, n-butyl methaoryiete, and particularly methyl methacrylate should be mentioned.
As starting substarzees of Formula t!!, such compounds in which ~4 or B
represent a branched or untrranched aikyiene group with 2 to b carbon atoms, e.g: -(CHZ)2~, -(C~)3 -(CH~,~., -CHZCH(CH~)CW2-, -CHZC(Chi3)?CHZ-, are possibte_ ... ._ _._ . .CA 02240196 2005-06-10 WO 97122592 g PCTIDI:96I0296'1 The number of ring elements of the heterocycle is preferably 5 and 6. It is particularly advantageous to use 1-(2-hydroxyethyl)-imidazolidine-2-vne, which can be easily produced on a technical scale, for example, in accordance with U.S: patent 3,254,075, from aminoethyt ethanoiamine and urea, as compound iit_ As calcium compounds which are added to the reaction system as catalysts or catalyst-forming precursors, the bivalent calcium compounds, such as calcium hydroxide, should be mentioned. It is practical to ease the calcium edmpovnds which #orm the catalyst, i.e.
the catalyst system, in catalytic amounts; in general not more than 250 ppm with referer?ce to the sum of the reaction partners i1 and 111. A high selectivity of product l with R, = CH3; A and 8 = -(Gl-i2}~= is achieved. for example, with 250 ppm Ga(f3,H~ with reference to the.total amount of reaction mixture, in the re-esterification of methyl rnethacrylate with the corresp4nding compound Ill.
It is advantageous if the catalysts are used in fine dispersion, for example in powder or mierocrystalline form.
The reaction of acryl esters and/or methacryl esters of Formula II with the alcohols of Formula )1l (alcoholysis) can be carried out at temperatures between 30 and 180 degrees C, particularly between 50 and 130 degrees C, preferably in the presence of not more than 250 ppm of the calcium compound, calculated on the basis of the weight of the reaction mixture.
~trding t~ the equation, equimoiar amounts of the reaction partners ii and (1i react to fog the desired end products 1. In practice, however, it ha> proven to be practical to always keep the starting esters II in excess during the reaction. 'They are preferably used in amounts of 1 to 20, preferably 2 to 10, particularly 3 to 6 males per mole Nl.
'lo avoid polymerization losses, it is preferable to carry out the reaction and processing of the reaction mixture in the presence of polymerization inhibitors such as phenothiazine;
hydroquinone monomethyl ether, and particularly oxygen.

The reaction can take place under standard pressure, greater pressure, or in a partial vacuum. It can take place discontinuously or continuously. The starting substances II
and III, for example, are heated to boiling together, in the presence of calcium compounds, and in this connection, the alcohol R20H which is split off is continuously distilled off with the ester II, possibly in the form of its azeotrope.
Depending on the reaction temperature, the catalyst, and the catalyst amount, the reaction times range from approximately 2 to 10J~ours. It is also possible to carry out the reaction in the presence of an inert solvent, for example toluene or cyclohexane, but this is normally not necessary.
After completion of the reaction, excess monomer ester II can be removed completely or partially, by distilling it off. The dispersed catalyst is usually removed by filtration, and it is advantageous to do so before distilling off the monomer ester II, which is mostly present in excess. However, it can also be removed only after partial or complete removal of excess monomer ester II. The catalyst, which is recovered in the filtered form, can then be used in other alcoholysis batches, if necessary after being dried.
A preferred reaction product is one that is formed from methyl methacrylate and 1-(2-hydroxyethyl)-imidazolidine-2-one (hydroxyethyl ethylene urea) and therefore corresponds to Formula I with R, = CH3, A = -(CH2)2- and B = -(CH2)2 .
EXAMPLES
Example 1 1100 g (11 mol) methyl methacrylate, 286 g (2.2 mol) hydroxyethyl ethylene urea, and 0.35 g hydroquinone monomethyl ether as well as 0.09 g phenothiazine as inhibitors are placed in a 2 liter round flask with mechanical stirring, air introduction, sump temperature display, and a filling element column WO 97122592 $ PCTIDE96102161 (diameter: 35 mm, height 55 cm, 8 x 8 mm - Raschig rings) set on it, as well as an automatic column head with reflux and distillate cooler.
The mixture is heated to boiling and first a methyl methacrylate water azeotrope is distilled off via the column, until the head temperature reaches 99 °C.
The batch is cooled by about 10 °C, 0.35 g calcium hydroxide and the mass of methyl methacrylate which is equivalent to the azeotrope distillate are added.
Again, the mixture is heated fo boiling, and the resulting methyl methacrylate methanol azeotrope is distilled off at a reflux ratio of 2:1, up to a maximum head temperature of 70 °C, later at a reflux ratio of 10:1, until a constant head temperature (99 °C) is reached. The reaction is terminated after 6 h. The batch is cooled to 80 °C and adjusted to a 25% solution of the product in methyl methacrylate by adding methyl methacrylate up to a total mass of 1742 g. 3.5 g Tonsil L80FF (Sudchemie) are added, and the batch is clarified by pressure filtration (Seitz pressure filter, diameter - 14 cm, filter layer T 1000 (Seitz) p < 0.4 bar). The filtrate has the following composition, according to gas chromatography analysis:
methyl methacrylate: 72.5%
hydroxyethyl ethylene urea: 1.4%
methacryloyl oxyethyl ethylene urea: 23.7%
N-(methacryloyl oxyethyl)-N'-(methacryloyl) ethylene urea: 1.2%
Example 2 Carried out as Example 1, but leaving out the water removal step. Reaction time: 5.3 h.

WO 97122592 g PCT/DE96102161 The product is composed as follows, according to gas chromatography analysis:
methyl methacrylate: 71.8%

hydroxyethyl ethylene urea: 1.7%

methacryloyl oxyethyl ethylene urea: 24.0%

N-(methacryloyl oxyethyl)-N'-(methacryloyl) ethylene1.2%
urea:

Platinum cobalt color number: 22 Acid number: _ 0.05 Example 3 Carried out as Example 2, but using 0.55 g calcium hydroxide. Reaction time:
5.5 h.
The product has the following composition, according to gas chromatography analysis:
methyl methacrylate: 70.5%
hydroxyethyl ethylene urea: 1.0%
methacryloyl oxyethyl ethylene urea: 24.4%
N-(methacryloyl oxyethyl)-N'-(methacryloyl) ethylene urea: 2.0%
Example 4 Carried out as in Example 2, but using 0.28 g (200 ppm relative to the total amount weighed in) calcium hydroxide. Reaction time: 6.0 h.
The product has the following composition, according to gas chromatography analysis:
methyl methacrylate: 71.3%
hydroxyethyl ethylene urea: 1.6%
methacryloyl oxyethyl ethylene urea: 25.1 N-(methacryloyl oxyethyl)-N'-(methacryloyl) ethylene urea: 0.7%

Claims (4)

1. Process for the production of (meth)acryl esters of the Formula I

in which R, stands for hydrogen or a methyl group and A and B stand for unbranched or branched alkylene groups with 2 to 5 C atoms, comprising the step of reacting in a reaction mixture an acrylic acid ester or methacrylic acid ester of Formula II

in which R1 is as defined above and R2 stands for an alkyl radical with 1 to 4 C
atoms, with a heterocyclic compound of the Formula III

wherein A and B are as defined above, in the presence of a catalyst system comprising calcium hydroxide, wherein said catalyst system is present in the reaction mixture in an amount of 1 ppm to 250 ppm based on the sum of compounds II and III.

2. The process of claim 1, wherein the amount of the catalyst system in the reaction mixture is 10 ppm to 150 ppm.

3. The process of claim 1 or 2; wherein the reaction of acryl or methacryl esters of Formula II is carried out with 1-(2-hydroxyethyl)-imidazolidine-2-one (2-(hydroxyethyl)ethylene urea).

4. The process of any one of claims 1 to 3, wherein methyl methacrylate as the compound of Formula II is reacted with an alcohol of Formula III.