DE1768622A1 - Process for the preparation of 2-hydroxyalkyl esters of unsaturated dicarboxylic acids - Google Patents

Description

Dr. Walter Beil
Alfred Hoeppener

Lawyers and notaries

Dr. Hans Joachim Wolff June 6, 1968

Dr. Hans Chr. Beil

Lawyers

Frankfurt a. M.-Höchst

58-Tel. 301024

Our no. 14 84 2

Pfizer Corporation
Colon / Panama

Process for the preparation of 2-hydroxyalkyl esters of unsaturated Dicarboxylic acids

The invention relates to a process for the preparation of 2-hydroxyalkyl esters unsaturated dicarboxylic acids by reacting vicinal epoxides with such acids. It affects in particular the use of a tertiary phosphine as a catalyst in this process.

For the conversion of vicinal epoxides with saturated or unsaturated carboxylic acids to obtain 2-hydroxyalkyl esters many catalysts are known, e.g. tertiary amines, iron (III) salts and lithium salts, however in many cases this leads to the use of such catalysts to an impure product that contains catalyst residues and other impurities, which affect the usability of the product. In the case of unsaturated dicarboxylic acids in particular, the product is often dark in color, unstable or otherwise unsuitable for homopolymerization or interpolymerization. It is then necessary to insert a cleaning stage to remove catalyst residues and / or other impurities, e.g. Vacuum distillation or precipitation of the impurities in insoluble, filterable form before such a product is further processed can be.

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According to the present invention is a 2-hydroxyalkyl ester an unsaturated dicarboxylic acid by reacting the acid with a vicinal epoxy in the presence of a catalytic amount of a tertiary phosphines produced.

The unsaturated dicarboxylic acids to which the invention is applied include maleic acid, fumaric acid and 2-methylene alkanedicarboxylic acid, such as itaconic acid and 2-methylene glutaric acid.

The term "vicinal epoxide" denotes all epoxy compounds of the formula R-QH-CH-R ¹ , in which R and R ^{1 represent}

Are hydrogen, alkyl or aryl groups, however the method is specifically applicable to the implementation of unsaturated Dicarboxylic acids with the lower alkylene oxides, i.e. ethylene oxide, 1,2-propylene oxide, 1,2-butylene oxide and 2,3-butylene oxide, as well as styrene oxide.

The tertiary phosphine catalyst can be any organophosphorus compound of the formula R.RpRoP in which R., Rp and R, represent an aryl group or an alkyl group, preferably a lower alkyl group, ie a group containing no more than 6 carbon atoms . Specific compounds that can be used are tri-n-butylphosphine and triphenylphosphine. The amount of catalyst is not critical and can range from 0.25% by weight , in which amount the reaction rate is quite slow, to 3% by weight, in which amount the reaction rate is very high and difficult to control. A useful amount of catalyst for good control of the reaction is about 1 wt. # Or about 0.25 Molji. These percentages relate to the amount of acid used.

To a polymerization of the unsaturated acid or its To prevent esters during the reaction, the acid is preferably a polymerization inhibitor, such as p-methoxyphenol, before the reaction added. The reaction can be started by heating if necessary, but it is exothermic and the reaction mixture may then need cooling to increase the build-up

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To prevent pressures. The reaction is preferably carried out in an inert atmosphere in a pressure vessel which is equipped with Inert gases such as nitrogen has been purged before the epoxy is introduced. The implementation will continue Ms the desired Acid number is reached, e.g. less than about 5 mg KOH / g for a largely neutral ester product, or a corresponding acid number for a 2-hydroxyalkyl partial ester of the acid. The unsaturated 2-hydroxyalkyl esters prepared according to the invention Dicarboxylic acids are largely colorless and can easily be removed without further purification, i.e. without removing catalyst residues be polymerized or copolymerized. However, if a removal of the catalyst residues or other impurities if necessary, this can be done by vacuum distillation of the product and / or precipitation of the catalyst residue in the form of an insoluble one Complex happens.

The following examples illustrate the nature is invention and the manner of their implementation. In these examples, all quantitative data relate to the weight (unless stated otherwise) and the temperature data relate to ° C. The molecular weights are based on the values of the bromine unsaturation, unless otherwise stated.
Example 1 :

910 g (7 moles) itaconic acid, 9.1 g triphenylphosphine and 0.4 g p-methoxyphenol were placed in a 4 liter stainless steel autoclave equipped with heating and cooling coils. The autoclave was purged with nitrogen and propylene oxide was introduced. After 1 hour, the temperature gradually rose to 100 ° raised while 1200 g (20.7 moles) of propylene oxide was added. An exothermic reaction occurred which enabled the Temperature for another 3 1/2 hours between 90 and 120 ° at a Maintain pressure between 0.7 and 2.8 atmospheres. The autoclave was then cooled to room temperature under nitrogen and the reaction mixture was transferred to a glass vessel and kept at 50 ° and 3 bis 4 mm Hg 15 minutes to remove unreacted propylene oxide evaporated.

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The product was an almost water-clear liquid with the following Characteristics:

Molecular weight 267

Acid number (mg KOH / g) 2.0

Viscosity at 25 ° (cS) 865.

The molecular weight indicated that the product consisted of 64 eolfo di (2-hydroxypropyl) itaconate and 36 mol # diester, which contained 3-oxypropylene units (for example according to US Pat. No. 1,109,920), or an average of about 2.4 oxypropylene units per molecule.
Example 2 :

A sample of the evaporated product from Example 1 was used successfully without further purification with methyl methacrylate and ethyl acrylate copolymerized according to the following recipe:

Product of Example 1 31.8 g (0.12 mol)

Methyl methacrylate 90 g (0.9 mol)

Ethyl acrylate 90 g (0.9 mol)

"Cellostilve ^II Acetate (Solvent) 212 g Azobisisobutyronitrile (Catalyst) 2.1 g. The monomers and solvent were placed in a flask and purged with nitrogen. One third of the catalyst was added and the temperature maintained for 1 1/2 hours. A further third of the catalyst was added and the same temperature was maintained for 1 hour. Then the last third of the catalyst was added and the temperature increased to 85 ° for 1/2 hour.

The white terpolymer was precipitated by pouring the product into excess 60/80 petroleum ether. After washing in a 4: 1 mixture of 60/80 ° petroleum ether and benzene, the terpolymer had a hydroxyl number of 66.2 mg KOH / g, from which it can be seen that the hydroxyalkyl monomer was completely incorporated into the terpolymer.
Example 3 :

9.07 kg (69.8 moles) of itaconic acid, 6 liters of benzene, 91 g of triphenylphosphine and 6 g of p-methoxyphenyl were poured into a 40 liter pressure reactor

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stainless steel, the one with stirrer and heating and cooling coils was equipped. The reagents were carefully purged with nitrogen and heated to the reaction temperature of 90 ° C. 15.0 kg (274.8 mol) of propylene oxide were during 2 l / 2 hours. At this temperature and at a pressure of 3.2 to 3.5 atmospheres added. An exothermic reaction occurred, under the effect of which the reaction mixture was kept at 90 without further heating could be. One hour after the propylene oxide addition was complete, the exothermic reaction began to subside; the The acid number of the mixture was then 43 mg KOH / g. 18I g (3.1 moles) Propylene oxide was added, and after a further 2 hours and 10 minutes at the same temperature, the acid number and the Pressure dropped to about 5 mg KOH / g. Benzene and excess propylene oxide were removed by heating to 60-90 ° at one pressure removed from 254 mm Hg in 45 minutes.

The end product was an almost water-clear liquid with the following Characteristics:

Molecular weight 273

Acid number (mg KOH / g) 5.86

p-Methoxyphenol content (TPM) 276

Ash (ppm) 29

According to the molecular weight and the low acid number, this product contained 46.6 mol ^ 2-hydroxypropyl _< / ~ 2- (2-hydroxypropoxy) propyl_7itaconate and 53.4 moldi (2-hydroxypropyl) itaconate or an average of about 2.5 oxypropylene units per molecule .
Example 4 ?

750 g (5.8 mol) of itaconic acid dissolved in 1500 g of isopropanol, which Contained 0.2 g p-methoxyphenol and 7.5 g triphenylphosphine, were placed in a 4 liter stainless steel autoclave. The mixture was carefully purged with nitrogen and heated to 90 ° C. 440 g (7.62 moles) of propylene oxide were made in 5 minutes added. The reaction was allowed to proceed at 90 and about 1.4 atm for the following 4 hours, after which time the Acid value was about 38Q mg KOH / g. The mixture was in a

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Glass container transferred, in which isopropanol and unreacted Propylene oxide was removed by evaporation under vacuum.

After evaporation, the product was a white, waxy pestilence, which showed the following analysis:

Acid number 381 mg KOH / g

Molecular weight 200.

These results show that the product contains hydroxypropyl partial esters of itaconic acid which have an average of about 1.2 oxypropylene units per molecule. Example 5 t

1000 g (7 | 7 mol) itaconic acid, 500 ml benzene, 0.6 g p-methoxyphenol and 10 g of triphenylphosphine were placed in a 4 liter stainless steel autoclave. The mixture was purged with nitrogen and heated to 90. 982 grams (16.9 moles) of propylene oxide were added over 40 minutes. The mixture was 8 l / 4 hrs at 2.1 to Maintained 2.8 atmospheres until no further decrease in the acid value was observed. At this point in time the acid number was 66 mg KOH / g. The product was transferred to a glass jar in which benzene and excess propylene oxide were heated to 50 at 4 to 5 mm Hg were removed.

The product was a pale yellow liquid with the following properties:

Molecular weight 273

Acid number (mg KOH / g) 60

Ashes 94 ppm.

These results show that the product contains hydroxypropyl partial esters of itaconic acid which have an average of 2.5 oxypropylene units per molecule.
Example 6 :

840 g (6 moles) of itaconic acid, 400 ml of benzene, 0.55 g of p-methoxyphenol and 8.4 g triphenylphosphine were placed in a 4 liter autoclave stainless steel. After carefully purging the mixture with nitrogen, the temperature was raised to 90 ° C. 1680 g (29.2 mol) of propylene oxide were added for 3 hours 20 minutes.

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added at 90 to 95 °. The pressure rose to 387 atm. To For a further 3 hours and 10 minutes at this temperature, the pressure had only fallen to 3.52 atmospheres. The mixture was cooled and in transferred to a glass vessel in which benzene and excess propylene oxide were removed by heating to 65 ° at 1.5 cm Hg. The end product was a water-insoluble, viscous liquid with the following properties:

Molecular weight 324

(determined from the dodecanethiol unsaturation)

Acid number (mg KOH / g) 0.01.

The results show that even in the presence of a substantial excess of propylene oxide, the product has a molecular weight which indicates that the product contains only about 3 oxypropylene units per molecule.
Example 7 :

Example 1 was repeated, but using tributylphosphine (1 _t based on the weight of itaconic acid) at a reaction temperature of 95 ° and a pressure of 2.8 to 3.5 atmospheres for 6 hours. The product was an almost water-clear liquid with the following properties:

Molecular weight 278

Acid number (mg KOH / g) 6.78

Ash (TpM) 147.

Corresponding to the molecular weight and the low acid number, the product contained 55 »2 mol # 2-hydroxypropyl (2- / ~ 2-hydroxypropoxy_7-propyl) itaconate and 44.8 mol # di (2-hydroxypropyl) itaconate with an average of about 2.6 oxypropylene units per molecule. Example 8 :

9.1 kg (69.8 moles) of itaconic acid, 6 liters of benzene, 90 g of triphenylphosphine and 6.0 g of p-methoxyphenol were placed in a 40 liter pressure reactor made of stainless steel, which is provided with heating and cooling coils and stirrer was equipped. After careful purging with nitrogen, the mixture was heated to a reaction temperature of 90 °. 9.5 kg (217 mol) of ethylene oxide were added over a period of 4 hours, the rate of addition being sufficient to achieve a pressure of 3.37 to 4.22 atm in the vessel. After further

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The acid number of the mixture was about 4.5 mg KOH / g for 2 3/4 hours at the same temperature and the same pressure. The jar opened Cooled 60 ° and excess ethylene oxide and benzene were removed at a pressure of 254 mm Hg. The product was a solid, water-clear liquid with the following properties: Molecular weight 258

Acid number (mg KOH / g) 4.68

Ash (TPM) 119

p-methoxyphenol content (TPM) 294.

Corresponding to the molecular weight and the low acid number, this product contained 90 moles of 2-hydroxyethyl (2- / f ~ 2-hydroxyäthoxy_J7äthyl) itaconate and 10 moles of di (2-hydroxyethyl) itaconate or an average of about 2.9 oxyethylene units per molecule. Example 9 *

A sample of the product of Example 8 was copolymerized using the following recipe:

Product of Example 8 31.8 g

Ethyl acrylate 90 g

Methyl methacrylate 90 g

250 ml

Solvent _11Q _

Methyl ethyl ketone toluene

Azobisisobutyronitrile (catalyst) 2.1 g. The monomers and solvents were placed in a flask and purged with nitrogen. A third of the catalyst was added and the temperature was increased to 75 ° in 1 1/2 hours. Another third of the catalyst was added and the temperature was kept at the same level for 1 hour. Then the last third of the catalyst was added and the temperature increased to 85 for 1/2 hour. The terpolymer was precipitated by pouring it into excess 60-80 ° petroleum ether. After thorough washing in 4: 1 petroleum ether / benzene, the polymer had a hydroxyl number of 63.9 mg KOH / g, from which it appears that at least 95 ° of the i Hydroxyalkylmonomers incorporated in the terpolymer was. Example 10 :

924 g (6.4 moles) of 2-methyleneglutaric acid, 600 ml of benzene, 0.4 g of p-methoxyphenol and 9.0 g triphenylphosphine were placed in a stainless

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4 liter autoclave. The jar and reagents were with Purged nitrogen and then heated to a reaction temperature of 90 °. 118 g (24.0 moles) of propylene oxide were added in 4 hours. An exothermic reaction occurred, the vessel being held at 90 ° by means of the cooling coil. After a further 3 hours at 90 ° and 2.46 atm the acid number of the product was about 1 mg KOH / g. The autoclave was cooled to room temperature and the reaction mixture transferred to a glass vessel in which benzene and excess Propylene oxide was removed by heating at 3 to 5 mm Hg. The product was a straw yellow liquid with the following Characteristics:

Molecular weight 273

Acid number (mg KOH / g) 0.01.

The molecular weight and the low acid number correspond to 77 * 6 organic di (hydroxypropyl) 2-methylene glutarate and 22.4 mol ^ 2-hydroxypropyl (2- / ~ 2-hydroxypropoxy_7propyl) 2-methylene glutarate (as described in patent application 43710/67) , or an average of about 2.2 oxypropylene units per molecule.
Example 11 :

1000 g (8.64 mol) fumaric acid, 10 g triph. Enylphosph.in, 0.4 g p-methoxyphenol and 600 g (10.3 moles) of propylene oxide were placed in a 4 liter autoclave made of stainless steel. The mixture was flushed with nitrogen and heated to a reaction temperature of 99 °. The reaction was sufficiently exothermic to maintain a temperature of 98-99 ° C. during the following 3 hours which time a further 920 g (15.9 mol) of propylene oxide was added became. After a further 1 l / 4 hour, the acid number of the mixture was about 3 mg KOH / g. Excess propylene oxide was removed by evaporation removed at 3 to 5 mm Hg in a glass jar. The product was a pale yellow liquid with the following properties: Molecular weight 251

Acid number (mg KOH / g) 2.99.

The product contains according to its molecular weight and acid number 34.5 moles of # 2-hydroxypropyl (2- / f * 2-hydroxypropoxy_J7propyl) fumarate and 65.5 moles of di (2-hydroxypropyl) fumarate or an average of about 2.3 oxypropylene units per molecule.

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Example 12 :

812 g (7 moles) of maleic acid, 8.1 g of triphenylphosphine, 200 g (3.45 moles) of propylene oxide and 0.32 g of p-methoxyphenol were placed in a 4 liter autoclave given. The mixture was stirred, purged with nitrogen and heated to 95 °. Another 816 g (14 moles) of propylene oxide were added over the course of 2 hours, the temperature being kept at 95 ° and the pressure at 2.88 atmospheres. After total The acid number had fallen to 6.6 mg KOH / g for 13 1/2 hours. The product was transferred to a glass vessel in which excess propylene oxide is removed at 30 to 35 ° and 3 to 5 mm Hg in 15 minutes became. The product was a yellow liquid with the following properties:

Molecular weight 261

Acid number (mg KOH / g) 6.61

p-methoxyphenol (TpM) 100.

EntspreAend the molecular weight and acid number, the product contained 51.7 i> 2-hydroxypropyl (2 - / "2-hydroxypropoxy_7propyl) maleate and 48.3 ° i di (hydroxypropyl) maleate, or an average about 2.5 oxypropylene units per molecule.
Examples I3 and 14 :

Example 1 was made using 0.25 # and 3 $ triphenylphosphine, based on the weight, repeated, with reaction times to achieve acid numbers of about 15 mg KOH / g (non-evaporated sample) of 17 hours or 2 hours were required. The product had the following properties:

Example 13 Example 14

Molecular weight 299 279 Acid number (mg KOH / g) * 10.7 0.55 Ash (tpm) 46 76 p-methoxyphenol content (TpM) 151 188

$ Three molar adduct, calc. From

the unsaturation 91.4 56.9.

* of the evaporated product (i at 3 'catalyst, reaction during sampling continued until a very niedri gen acid value); the stripped product usually has a higher acid value because of the removal of diluents.

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This analysis shows that the substance obtained with 3 </ ° catalyst contained an average of 2.6 and the material produced with 0.25 1 ° catalyst contained an average of about 2.9 oxypropylene units per molecule.
Examples 15 and 16 ;

Samples of the stripped product of Examples "B and 14 were tested with Ethyl acrylate and methyl methacrylate copolymerized according to the procedure of Example 2. After precipitating and washing, each had Terpelymer has a hydroxyl number of 65 mg KOH / g, from which it can be seen that in each case all of the hydroxyalkyl monomer had been incorporated into the terpolymer, despite its presumed presence to a significant extent Amounts of phosphine catalyst residues (in example 16) «

Examples 17 to 20 ;

Terpolymer solutions prepared according to Examples 2, 9 »15 and 16 became tough, clear, pliable, thermosetting films through their hydroxyl groups by the following procedure networked;

14 g of terpolymer was mixed with 3 g of hexamethoxymethylmelamine (Beetle BE. 670) in ^lt Cellosolve "acetate (7 g) and 0.10 g of p-toluenesulfonic acid / lsopropynol / distilled water in the ratio 20/78/2 (wt. The clear solution was then painted onto a tin plate and placed in an oven at 120 ° for 30 minutes, a clear, colorless, flexible film being formed.

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Claims (7)

Claims 1.) Process for the preparation of 2-hydroxyalkyl esters of unsaturated dicarboxylic acids by catalyzed reaction of the acids with
a vicinal epoxide, characterized in that a tertiary phosphine is used as the catalyst. 2.) The method according to claim 1, characterized in that the tertiary phosphine in amounts of 0.25 to 3 wt. ^, preferably about 1% by weight, based on the acid, used. 3.) The method according to claim 1, characterized in that as Acid maleic acid, fumaric acid or a 2-methylene alkanedicarboxylic acid, such as itaconic acid or 2-methylene glutaric acid used. 4.) The method according to claim 1, characterized in that the epoxide is ethylene oxide, propylene oxide, 1,2- or 2,3-butylene oxide or
Styrene oxide is used. 5.) The method according to claim 1, characterized in that as Catalyst tributylphosphine or triphenylphosphine used. 6.) The method according to claim 1, characterized in that the Reaction in the presence of a polymerization inhibitor such as p-methoxyphenol performs. 7.) The method according to claim 1, characterized in that the implementation is carried out until the acid number of the reaction mixture is less than about 5 mg KOH / g, with a largely neutral diester of the acid is formed. For Pfizer Corporation
Colon / Panama (Uw Lawyer
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