SU438177A1 - The method of producing esters of acrylic acid - Google Patents

Description

one

The invention relates to the development of a new method for the preparation of acrylic esters, which are good monomers in the manufacture of polymeric materials.

A known method for producing acrylic acid esters based on acetylene and carbon monoxide with a good yield of the target product.

The proposed method expands the raw material base for the production of esters and expands the number of methods for their preparation.

The proposed method is based on the thermal decarboxylation of the copper salt (both monovalent and divalent, with the content of one copper atom per mole of monoether) of the 1,2-ethylene dicarboxylic acid myoether in the presence of compounds with a tetragon nitrogen atom in the ring, polymerization inhibitors, for example hydroquinone, pyrocatechin, Indulin, and alcohol, which is included in the alkyl component of the original monoether. B as the copper salt of the monoether 1,2-egilendicarboxylic acid, it is better to use maleic monoether with 1-4 carbon atoms in the aliphatic residue, or monoesters of primary or secondary alcohols with 4-10 carbon atoms, or my cyclohexyl, or monobenzyl ester of maleic or fumaric acid.

When pyridine or quinoline or acridine is used, the decarboxylation rate increases, and when pyrrole is used (secondary nitrogen atom with an aromatic character), the reaction rate decreases.

Triphenylamine is also weak.

The process is carried out at 100-29 ° C (the upper limit is due to the instability of the monoether salt) in an excess of the monoether salt (fourfold) to prevent its expansion: in an organic solvent, such as ketone.

In addition, the addition to the reaction medium of silk agents, such as carbon dioxide

Calcium, and sodium sodium, helps to increase yield. If the process is carried out to obtain the copper salt of the monoester acid in the reaction itself, then it is necessary to take an excess of the copper compound relative to the monoester and the corresponding acid.

Example 1. Obtaining methyl methacrylate lead by continuous decarboxylation of COOH

CH-COOCu

i- CuoO-- COOR

CH-COOR (a-sns)

no monomethylmaleine single salt according to the equation

CH-COOR

+ CtiOH-I Clho

+ c on + c; unO

The process is carried out in a four-necked (500 ml) round-bottomed flask equipped with a deep-drawn dropping funnel, a thermometer, a stirrer, and a side column (20 cm long) with a conventional distillation apparatus attached to it, an adjustable head fraction with reflux condenser, a direct coil cooler graduated a forshtosom, a receiver with an attached freezing trap at -70 ° C and a pot with 33% alkali for carbon dioxide absorption.

180 g of quinoline, 14.3 g (0.1 mol) of cuprous oxide and 1 g of Indulin as a polymerization inhibitor are introduced into a quadrangular flask. Heated with stirring to 220 ° C, then poured from a dropping funnel with stirring a solution of 1 mol of monomethyl maleinate in 5 mol of methanol at a rate of 0.19 mol of monomethyl maleinate in 1 hour. A continuous mixture of methyl acrylate and methanol with a boiling point of 59 ° C is distilled off from the column with continuous CO 2. Prilification is complete after the introduction of 0.57 mol of monomethyl maleate. The transformation calculated from the total amount of absorbed Cu2O and equal to 23.8 g (about 95% of the theoretical). Distillate contains 40.9 g of methyl acrylate, which corresponds to 83.4%.

As the amount of cuprous oxide increases, the decarboxylation rate increases to a quantitative conversion. The yield of acrylic ester is increased to 90% of theoretical and more. By reducing the amount of cuprous oxide to 7.15 g (0.05 mol) and passing 7.5 times the amount (0.375 mol) of monomethyl maleate, but at the same rate the conversion is 87.5% and the yield of acrylic ester is more than 75 % of theoretical. In all experiments, the introduced copper oxide can be fully regenerated.

Example 2. Production of ethyl acryl by continuous decarboxylation of the monoethyl aleic acid metal salt.

The reaction equation is cf. as in Example 1 (R-CzHs).

The experiment was carried out using the apparatus described in Example 1. The same experimental conditions were observed, and a 5.5 molar excess was used.

CH-COOH II

+ duo CH-SOOSNz

monoethyl maleinate (0.55 mol) to 2.75 mol of ethyl alcohol, on taken cuprous oxide (0.1 mol).

The transformation of 93.7% of theoretical, the yield of ethyl acrylate on the reacted maleinat 84.75%. Purified copper oxide recovered without loss.

Example 3. Preparation of butyl acrylate by negfer decarboxylation of the mono-butylated malehydroxide salt. The equation

the reaction is the same as in example 1.

However, a one-four-neck round-bottom flask was used, and a column with a nozzle was 35 cm long.

250 g of quinoline, 14.3 g (0.1 mol) of cuprous oxide, 0.56 g (0.01 mol) of potassium hydroxide, 2 g of indulin and 1 g are introduced into a four-necked flask.

pyrocatechin. The last two serve as polymerization inhibitors. The mixture is heated to 223 ° C. with stirring. At the beginning of the experiment, 35 g of n-butyl alcohol are added to it. In the calculation of cuprous oxide, (0.01 mol), a tenfold molar amount of monobutyl maleate is used, i.e., 1 mol of it; maleate is dissolved in 4 mol of butanol. The transfer rate of maleate is 0.45 mol / h.

The reaction product, a butanol-butyl acrylate buganol solution, is distilled off under conditions of mild reflux.

Distillate contains 11.5 g of butyl acrylate, which corresponds to 98.5% of the theoretical value. By

Otsh, the amount of carbon dioxide melted conversion of 93.5%. Thus, the yield of butyl acrylate per total conversion is quantitative (100%). The distillate cannot detect oxidation products (butyraldehyde); in accordance with this, copper oxide is quantitatively regenerated.

In another experiment carried out similarly, in terms of the higher consumption of maleate (0.37 mol / h), quantitative

conversion and quantitative yield of acrylate.

Example 4. Preparation of methyl acrylate by continuous decarboxylation of the basic oxide-copper monomethyl maleate salt at a temperature of 100 ° C and higher. Reaction equation

CH-COO-SaON /

Ii. 4- CuO

CH-SOOSYz

The equipment is the same as in example 1.

Into the three-necked flask, 8.7 g of copper oxide (0.11 mol), as well as 0.2 g of Indulin and 0.2 g of methylene blue as a stabilizer, are introduced. As a reaction medium for each of the individual four experiments, 200 g of the following solvents were used:

dimethylformamide (DMF) (A),

a mixture of 95% DMF and 5% pyridine (B);

a mixture of 75% DMF and 25% pyridine (B);

pyridine (r).

The mixtures are heated to low boiling with stirring (temperature 152, 152, 130, and about 100 ° C, respectively, for experiments A, B, C, and D). The consumption of monomethyl maleinate in the form of a solution of a five-fold molar amount of methanol in each experiment is 0.615 mol.

In Experiment A, i.e., with pure DMF and 152 ° C, no decarboxylation was observed.

In experiment B, i.e., with the use of DMF with 5% pyridine, the conversion was 57%, the yield of the isolated methyl acrylate was 53.4%. Thus, based on the converted product, the yield is 93.6%.

In the experiment B at 130 ° C, the conversion was 40%, the yield of acrylate calculated on the basis of the process. rotated maleate 52.3%.

Finally, in experiment G, i.e. prp 100 ° C, under similar conditions, the conversion is 31.4%, the yield of acrylate per nCr fermented product is 24%. With further further heating, C02 was again cleaved, so that at the end the total conversion was 87%.

The residue contained acrylate, mainly in the form of a polymer soluble in chloroform. In addition, a crystalline compound was isolated, which could occur, as indicated by its composition, by adding a pyridine molecule to a maleic anhydride or monomethyl maleate molecule.

Pr-Immer 5. When the solution was dicarboxylated, 0.228 mol of monomethylmalnenate in 1.14 mol of methanol in the presence of a suspension of 14.3 g of cuprous oxide, in 171.7 g of dimethylformamide and 8.3 g of pyridip at a reaction temperature of 150 ° C, the conversion was a little less than 35%, the amount of acrylate released is 34.7%. Output B calculating pa converted maleate is almost quantitative. With slow transmission, you can increase the conversion.

Example 6. By a known method, a solution of monomethyl maleinate in a fivefold molar amount of methanol was prepared in a large amount; this solution is stabilized with 0.05% hydroquinone. It is passed into a bath of 7.95 g of copper oxide, 172 g of quinoline, and 0.5 g of Indulin or indicator, for which purpose a dosing funnel is immersed in a liquid by 4 cm. The bath is continuously mixed with bringing it to temperature by external heating to 221-223 (±: 5) ° С.

The pyrolyzate is passed through a nozzle.

a 15 cm long column is roughly denoted 1 in the Claisen bridge and a direct ball refrigerator. The exhaust gases are passed through a trap cooled to a temperature of from -70 to -80 ° C and then sent to kalyapnarag with a 15% sodium hydroxide solution for hydrogen dioxide, carbon dioxide. The rate of priming of the monomethyl malein solution is on average from 0.5 to canel / sec. After passing

153 g of the solution (about 165 ml) was used to calculate the yield of methyl acrylate and conversion (according to the CO2 cleavage data). In all cases, 23.2 to 23.3 g of COz were found, which corresponds to the theoretical optimal values.

(99-100%). The yield of acrylate, determined by measuring the saponification and bromine numbers, is for a first pass 80.6% of theoretical, in chronological order of 93.4; 98; 99; 97; 99.7%. After stop

after several days of experience, the bath turned out to be again suitable for decarboxylation, retaining the original activity; due to the slight formation of the polymer, the bath weight increased by 3.3 g.

Example 7. 79.5 g of copper oxide and 130 g of mopomethyl maleate are introduced into 64 g of methanol. This mixture, containing the formation; uus oxide 0, the monomethylmalein-a copper salt, is mixed with 820.5 g of quinoline. The mixture is heated at

stirring until kpepi. At 90 ° C, decarboksplirova 1 does not begin. The rate of this reaction increases at 120 °. The llpenpan is about 80%. Example 8. Decarboxylation of a solution of 29.6 g (0.228 mol) of monomethyl fumarate in 1.14 mol% of methanol was carried out by passing the solution for 1 hour through a suspension of 14.3 g of copper oxide in 171.7 g of dimethylformamide and 8.3 g of pyridine at 150 ° C. The conversion is 35%, the yield of acrylate is 34.7%. Thus, based on the reacted fumarate, the yield is almost quantitative, and with a slower passage of the solution, the conversion to the target

product can be increased.

Subject invention

Claims (4)

1. A method for producing acrylic esters, characterized in that single-salt salt of the corresponding complex mono-1,2-ethylene dicarboxylic acid is subjected to thermal decarboxylation at a temperature of 100-290 ° C in the presence of compounds containing a tertiary atom ring nitrogen, a polymerization inhibitor, alkaline compounds and the alcohol component of the starting monoester. 2. A method according to claim 1, characterized in that pyridine, quinone, is used as compounds containing a tertiary nitrogen atom in the ring. 3. The method according to claim 1, characterized in that indulin, pyrocatechin, hydroxonone are used as polymerization inhibitors. 4. The method according to which, as 78 p. I, characterized in that sodium alkali or bicarbonate of alkaline compounds is applied is calcium. 438177