DE1267214B - Process for the preparation of unsaturated ester isocyanates - Google Patents

Description

Process for the preparation of unsaturated ester isocyanates It is already known, polymerizable ester isocyanates from the esters of primary amino alcohols with unsaturated polymerizable carboxylic acids or halogen fatty acids corresponding to these produce by the in a known manner by esterification of the hydrochloride primary amino alcohols with the corresponding unsaturated polymerizable carboxylic acids or amino ester hydrochlorides produced by these corresponding halogenated fatty acids converted with phosgene in a known manner into the isocyanates and optionally from the halogenated ester isocyanates formed in a manner known per se splits off. This process is described in German patent specification 1018 050.

As has been found, these reactions occur only with smaller ones Approaches with good yield.

However, if larger amounts of such esteramine hydrochlorides are phosgenated, then always occurs during the distillation of the ester isocyanates remaining in the bottom after a short distillation a polymerization, so that maximum yields of 300 / o can be obtained. In addition, the is deposited during the conversion of the esteramine hydrochloride Hydrogen chloride split off with phosgene is partially bound to the hydrocarbon double bond the unsaturated acid.

The accumulated hydrogen chloride must then subsequently be catalyzed Ways or by adding tertiary amines are split off again.

It has now been found that this process can be decisively improved can, if one unsaturated esteramine hydrochloride of the general formula R - COO (CH2) nNH2 HCl in which R is an unsaturated hydrocarbon radical and n is a number between 2 and 10 means at temperatures between 70 and 180 "C, preferably 90 to 140" C, treated with phosgene using diphenyl ether or a substituted solvent Diphenyl ether used.

The radical R in the formula preferably denotes the hydrocarbon radical of acrylic acid, methacrylic acid, crotonic acid, cinnamic acid and styrene carboxylic acid.

Due to the easy solubility of the Esteraminhydrochloride in these Solvents the phosgenation time is reduced and also allowed these high-boiling solvents that the unsaturated isocyanates formed in in many cases can be distilled off from the solvent mixture. The yields according to this procedure - if it is carried out on a larger scale - are included 70 to 80 per cent of theory. In addition to diphenyl ethers, there are also substituted solvents Diphenyl ether into consideration, such as. B.

2-nitrodiphenyl ether, 4-chloro-2-nitrodiphenyl ether, 3-nitrodiphenyl ether, 4-nitrodiphenyl ether, 2,2'-dimethyldiphenyl ether, 3,3'-dimethyldiphenyl ether, 4,4'-dimethyldiphenyl ether, 2'-nitro-4-methyldiphenyl ether, 4'-nitro-dimethyldiphenyl ether.

The process itself is carried out so that, for. B. alkylolamine hydrochlorides in solvents such as chlorobenzene, toluene, etc. with unsaturated acyl halides at temperatures between 50 and 100 "C to react. After splitting off the The calculated amount of hydrogen halide is then cooled to room temperature and the solidified unsaturated Esteraminhydrochloride sucked off. Most of the time it is enough the pure hydrochloride obtained after a short wash in diphenyl ether or its Include substitution products and the phosgenation preferably at 90 to 140 "C. The dissolved esteramine hydrochlorides are through the phosgene is rapidly converted into the carbamic acid chlorides or isocyanates.

In order to obtain a good yield, it is advantageous to introduce more phosgene, than the theoretical amount, preferably about 0.3 to 1.0 mol Phosgene was added in excess per mole of esteramine hydrochloride. Of course these reactions can be carried out in the presence of polymerization inhibitors carry out, to avoid any premature polymerisation. Has proven particularly effective here is phenothiazine. After the phosgenation has ended, the excess Amounts of phosgene and hydrochloric acid formed removed with an inert gas stream and then the isocyanate formed is distilled out of the solution. Mostly fall the isocyanates formed in such a pure form that a further rectification is possible unnecessary. Should in some cases an addition of hydrochloric acid to the hydrocarbon formation take place, it is advantageous to use unsaturated hydrocarbons at the same time as the phosgene stream initiate, such as B. isobutylene, butadiene, etc.

Example 1 a) Representation of CH2 = C - COOCHCH2NH2HCl (I) CH In a slurry of 3660 parts of ethanolamine in 15000 parts by volume of absolute chlorobenzene hydrogen chloride is passed in until saturation is reached.

The temperature is kept above 70 ° C. Then 4 Parts of phenothiazine are added and at 70 to 80 ° C. 7800 parts of methacrylic acid chloride dripped in. The mixture is subsequently stirred at this temperature for 2 to 3 hours.

The esteramine hydrochloride precipitates on cooling or standing overnight. It is suctioned off and washed out with a little acetone (2500 to 3000 parts by volume). The product is dried in vacuo. The yield is 75 to 80%. b) Representation of 10,000 parts of esteramine hydrochloride I, 100 parts of phenothiazine and 15,000 parts of distilled 2-nitrodiphenyl ether are heated to 110.degree. The esteramine hydrochloride dissolves quickly. At this temperature, 12,000 parts of phosgene and 11,000 parts of isobutylene are introduced at the same time. After the solution has been blown out with nitrogen, the isocyanate is obtained without first runnings in a yield of 75% (boiling point 12 90 to 95 "C), n2D = 1.4496.

The solvent remains as a residue (b.p. 10 182 to 1850 C), which can be recovered almost quantitatively by distillation.

Example 2 a) Representation of CH - CH = CH - COO (CH2) 2NH2HCl (m) In the manner indicated in Example 1, 366 parts of ethanolamine are used in 1500 parts by volume absolute chlorobenzene saturated with hydrogen chloride and after the addition of 4 parts Phenothiazine esterified with 772 parts of crotonic acid chloride.

After cooling, the esteramine hydrochloride is filtered off with suction and with washed out about 300 parts by volume of carbon tetrachloride. The hydrochloride is im Vacuum dried. The yield is 80%. b) Representation of CH-CH = CH-COO (CH2) 2NCO (IV) 1000 parts of esteramine hydrochloride III are used in 1500 parts of 3,3'-dimethyldiphenyl ether dissolved with the addition of 10 parts of phenothiazine. At 110 "C, 1200 parts of phosgene graze initiated. After purging the solution with nitrogen, distillation takes place the crotonic acid ester isocyanate in 820 /, the yield (bp 9 99 to 101 "C).

Example 3 a) Representation of As in Example 1, a suspension of 450 parts of propanolamine in 1700 parts by volume of absolute chlorobenzene is saturated with hydrogen chloride and, after the addition of 4 parts of phenothiazine, is reacted with 780 parts of methacrylic acid chloride at 70 to 800.degree.

The yield is 770%. b) Representation of After adding a solution of 1000 parts of esteramine hydrochloride V in 1500 parts of 2'-nitro-4-methyl-diphenyl ether with 10 parts of phenothiazine, 1100 parts of phosgene are passed in at 110.degree.

After purging the solution with nitrogen, distillation takes place the methacrylic ester isocyanate in 750/0 yield (bp 13 112 to 114 "C, and = 1.4562).

Example 4 a) Preparation of CH2 = CHCOOCH2CH2NH2HC1 (VII) As in Example 1 given, 366 parts of ethanolamine in 1500 parts by volume are absolute Chlorobenzene saturated with hydrogen chloride and after the addition of 4 parts phenothiazine reacted with 633.5 parts of acrylic acid chloride to give the corresponding esteramine hydrochloride. After drying in vacuo, the esteramine hydrochloride is obtained in a yield of 76%. b) Preparation of CH2 = CHCOO (CH2) 2NCO (VIII) in a solution of 500 parts of esteramine hydrochloride VII in 750 parts of 2,2'-dimethyldiphenyl ether become phenothiazine after addition of 5 parts at 110 to 120 "C phosgene and isobutylene introduced at the same time. After blowing out the solution with nitrogen is obtained by distillation in 750% yield Isocyanate (bp 85 to 87 "C, n2D = 1.4551).

Claims (2)

Claims: 1. Process for the preparation of unsaturated ester isocyanates of the general formula R - COO (CHl) fl NCO in which R is an unsaturated hydrocarbon radical and n is a number between 2 and 10 by reacting esteramine hydrochlorides of the general formula R - COO (CH2) flNH2 HCl in which R and n have the abovementioned meaning have, with phosgene at temperatures between 70 and 180 "C, characterized that the reaction in diphenyl ether or a substituted diphenyl ether as a solvent is carried out. 2. The method according to claim 1, characterized in that with the Phosgene are introduced at the same time unsaturated hydrocarbons.