IE41812B1 - Unsaturated phophorus-containing carboxylic acid derivatives - Google Patents

Abstract

Novel unsaturated phosphorus-containing carboxylic acid derivatives of the formula I are prepared by reacting an alcohol of the formula II with a compound of the formula III. The individual symbols are as defined in Claim 1. The reaction is carried out in an inert solvent. The resultant compounds of the formula I are suitable as monomers or comonomers in the preparation of polymers.

Description

This invention relates to unsaturated phosphorus-containing carboxylic acid derivatives.

Unsaturated phosphorus-containing carboxylic acid derivatives of tho formula CH 0 0 \ H , s » x P-(CH„) OC-C-CH, Z I CH„ in which R^ is hydrogen or a methyl radical and n is 1, 2 or 3, are already known (German Offenlegungsschrift No. 2,052,569).

They are derivatives of tertiary phosphine oxides which have good flame retarding properties. The starting material for their preparation is generally dimethylchlorophosphine which, simultaneously with methyldichlorophosphine, is obtained industrially by reacting methyl chloride with phosphorus at about 350°C (German Auslegeschrift No. 1,568,928). A similar flame-proofing application for methyldichlorophosphine is not known, and this makes the use of dimethylchlorophosphine uneconomic.

The present acid derivatives invention provides phosphorus-containing carboxylic of the formula ,1 R X 0 \JI II P-Y-0-C-C=CH„ X I 2 r20 r3 (I) in which each of R^ and R2 is an alkyl radical having up to 8 carbon atoms, preferably an alkyl radical having from 1 to 4 carbon atoms; R^ is hydrogen or a methyl radical; X is oxygen or 41813 sulfur, preferably oxygen; and Y is a linear or branched alkylene radical having up to 6, preferably from 1 to 3, carbon atoms.

The present invention also provides a process for the preparation of compounds of the formula (I), which comprises reacting an alcohol of the formula P-Y-OH (II) r2o in which Rp Rp X and Y have the meanings given above, with a compound of the formula ίο z-co-c=ch2 (III) R3 in which Z is a halogen atom, preferably a chlorine atom; and R^ has the meaning given above, in the presence of an inert solvent and in the absence of water.

The acylation according to the present invention of alcohols of the formula (ll) with acrylic or methacrylic acid halides of the formula III is carried out in known manner, preferably in the presence of a hydrogen halide-binding compound, for example a tertiary amine such as triethylamine or pyridine, at a temperature of from -30 to +100°C, preferably from 20 to 7θ°0. The hydrogen halide-binding compound is used in an equimolar amount relative to the acid halide of the formula (III), or in a slight excess of up to about 10%.

It is also preferred to use one of the polymerization inhibitors known for acrylic acid derivatives, for example phenothiazine, hydroquinone, hydroquinone-monomethyl ether and/or metal salt inhibitors. The amount of inhibitor is chosen within the usual range, for example from 0.01 to 1 weight %, relative to the compound of the formula (III), The presence of active polymerization inhibitors is important also for the optional distillation work-up of the crude reaction mixture.

The starting compounds of the formulae (II) and (III) are generally used in about equimolar amounts; the acid halide of the formula (III) optionally being in a slight excess of up to 10%.

The reaction is carried out with the exclusion of water.

Tho reaction is advantageously carried out as follows: the alcohol of the formula (E) and the optional tertiary amine in the inert solvent are first introduced into the reaction vessel at room termpera.-fcui'i2}arid the acid chloride of the formula (III) is added dropwise, while the mixture is continuously and thoroughly mixed, for example by means of an agitator.

The reaction temperature is not critical and may rise within the above mentioned temperature range, that is, up to 100°C because of the reaction heat liberated during the reaction, and this may be advantageous for the course of the reaction. The starting compounds of the formula (II) are easily obtainable.

For example hydroxymethyl-alkylphosphinic acid esters according to the process of German Offenlegungsschrift No. 2,226,406. 2hydroxyethyl-alkylphosphinic acid esters are obtained in good yields from 2-acetoxy-ethyl-alkylphosphinic acid esters according to the process of German Offenlegungsschrift No. 2,335,852, and 3, hydroxypropyl-alkylphosphinic acid esters may be prepared in an analogous manner.

Typical phosphorus containing carboxylic acid derivatives of the formula (I) are for example: the acrylic and methacrylic acid esters of methylhydroxymethyl-phosphinic acid methyl, ethyl, propyl and isobutyl esters; ethyl-hydroxymethylphosphinic acid methyl, ethyl, propyl and isobutyl esters; ethyl-hydroxymethylphosphinic acid methyl, ethyl, propyl and isobutyl esters; methyl-2hydroxyethylphosphinic acid isobutyl ester; methyl-2-hydroxyethylthiophosphinic acid isobutyl ester; propyl-2-hydroxyethyl- 4 41812 phosphinic acid propyl ester; methyl-(2-hydroxy-2-melhylethyl)phosphj.nic acid methyl, ethyl, propyl, n-butyl, isobutyl and pentyl esters; methyl-3-hydroxypropylphosphinic acid isobutyl ester; and butyl-3-hydroxypropylphosphinic acid isopropyl ester.

As inert solvents theremay be used for example those solvents which are usually employed for esterification and/or ester interchange reactions, such as benzene, toluene, xylene, chlorobenzene, carbon tetrachloride, chloroform, diisopropyl ether, acetonitrile and mixtures of such compounds. The amount of inert solvent is not critical and depends advantageously on the stirability of the reaction mixture after complete reaction, in which the hydrogen halide-binding compound optionally used precipitates generally as a hydrohalide in the form of crystals. Therefore, the inert solvent is generaly used in an amount of up to 10 times, preferably from 2 to 5 times, the weight of the alcohol of formula (ll).

Xylene or toluene are the preferred inert solvents.

Because of their unsaturated carbon-carbon bonds, the carboxylic acid derivatives of the formula (I) are suitable as monomers or comonomers for the preparation of polymers. For example, by copolymerization with monomers such as acrylic derivatives, styrene or vinyl compounds, flame retarding polymers having improved dyeability and anti-static properties are obtained. Copolymers consisting of acrylonitrile, vinyl chloride, vinyl bromide and/or vinylidene chloride and compounds of the formula (I) have surprisingly good flame retarding properties. Furthermore, filaments and fibres made from these copolymers have an unexpected high thermostability, that is, their tendency to yellowing under thermal stress is considerably less than that of similar materials known in the art.

By ester interchange of the phosphinic acid ester groups «Rg (preferably when Rg is an alkyl radical having from 1 bo 4 carbon atoms, especially methyl or ethyl) with glycols such as - 5 41812 ethylene glycol, diethylene glycol, propylene glycol or higher glycols, the polymers obtained may also be cross-linked. When using methyldichloropfiosphine as the starting material for the preparation of the alcohol of the formula (IX). The phosphinic acid esters of the formula (I) are more easily obtainable than the analogous tertiary phosphine oxides, which require the use of dimethylchlorophosphine as starting material. In contrast to dimethylchlorophosphine, methyldichlorophosphine is easily manufactured on an industrial scale, since it may be obtained in known manner and as exclusive product from the reaction of methane with PC13 at 600°C.

The following Examples illustrate the invention.

EXAMPLE 1 252 g (1.52 mol) of methylhydroxymethylphosphinic acid isobutyl ester, 153 g (l.52 mol) of triethylamine and 1 g of phenothiazine are dissolved in toluene and, with agitation and slight cooling, 137-5 g (1.52 mol) of acrylic acid chloride are added dropwise at 2O-3O°C. Agitation is continued for 15 hours. After one further hour, the triethylamine hydrochloride precipitated is suction-filteVed. After having distilled off the solvent and after addition of polymerization inhibitors, the filtrate is distilled in vacuo. 185 g of CH, 0 < || P-CH,-O-C-CH=CH , “ li (CH3)2CHCH2O 0 boiling point 95-9S°C at 0.1 mm Hg, are obtained, which corresponds to a yield of 55-5$ of the theoretical yield.

Analysis: found: C 49.3$; H 7.7$; P 14.0$ calculated: C 49.1$; H 7.72$; P 14.1$. - 6 41812 EXAMPLE 2 500 g (2.78 mol) of methyl-2-hydroxyethylphosphinic acid isobutyl ester, 28l g (2.78 mol) of triethylamine and 1.5 g of phenothiazine are dissolved in 1.67 1 of toluene and, with vigorous agitation and without cooling, 252 g (2.78 mol) of acrylic acid chloride are added dropwise. The temperature rises to 50°C. After the chloride is added, agitation is continued for 15 hours. Subsequently, the batch is cooled to 1O°C, and the triethylamine hydrochloride precipitated is eliminated by suctionfiltration. After having distilled off the solvent in a water jet vacuum and after addition of polymerization inhibitors, the residue is distilled in vacuo. 4§5 g of CH, 0 < if P-CH„-CH„-0-C-CH=CH_ / II (CH3)2CHCH2O 0 boiling point 145°C at 2 mm Hg, are obtained, which corresponds to a yield of 75% of the theoretical yield.

Analysis: found: C 51.4%; H 8.10%; P 13.0% calculated: C 51.3%; H 8.12%; P 13.25%.

EXAMPLE 3 188 g (1.04 mol) of methyl-2-hydroxyethylphosphinic acid isobutyl ester, 105 g (1.04 mol) of triethylamine and 0.5 g of phenothiazine are dissolved in 620 ml of toluene and, with vigorous agitation and without cooling, 109 g (1.04 mol) of methacrylic acid chloride are added dropwise. The temperature rises to 50-6O°C.

After the chloride is added, agitation is continued for 10 hours, and the batch is cooled to -10°C. The triethylamine hydrochloride precipitated in the form of crystals is eliminated by suctionfiltration, and the filtrate is substantially liberated from the toluene at 120°C and 35 mm Hg. After addition of polymerization inhibitors, the residue is distilled in vacuo. 220 g of - 7 10 CH Ο il PCH2CH2OC~C=CH2 (ch3)2chch2o ΰ CH3 boiling' point 125-131°C at 0.45 mm Hg, are obtained, which corresponds to a yield of 85%.

Analysis: found: C53.2#; Η 8.47#; P 12.5# calculated: C53.6#; H 8.5#; P 12.4#.

EXAMPLE 4 g (0.385 mol) of methyl-(2-hydroxy-2-methylethyl)-phosphinic acid isobutyl ester, 39 g of triethylamine (0.385 mol) and 0.3 g of phenothiazine are dissolved in toluene and, with slight cooling 35 g (0.385 mol) of acrylic acid chloride are added dropwise. Agitation is continued for 12 hours. After a further hour, methylene chloride is added, and the triethylamine hydrochloride is suction-filtered. The filtrate, after having eliminated the solvent and added polymerization inhibitors, is distilled under reduced pressure. 57.5 g of CH_ 0 II li P-CH2-CHOC-CH=CH2 (ch3)2chch2o ' CH3 boiling point 95“1θθ°^ θ·1 1111,1 Hg, are obtained, to a yield of 60# of the theoretical yield. Analysis: found: C 53.4#; H 8.5#; calculated: C 53.6#; H 8.5#; which corresponds P 12.5# P 12.4#.

EXAMPLE 5 196 g (1 mol) of methyl-2-hydroxyethylthipphosphinic acid isobutyl ester, 101 g of triethylamine (1 mol) and 0.4 g of phenothiazine are dissolved in 500 ml of toluene and, with vigorous agitation and without cooling, 104.5 g (l mol) of methacrylic acid - 8 25 41813 chloride are added dropwise. The temperature rises to 50°C. Agitation is continued for 5 hours, and the batch is allowed to stand overnight. Subsequently, it is cooled, and the triethylamine hydrochloride is suction-filtered. The filtrate is stirred with water, the organic phase is separated and dried with Na2S0^. After having distilled off the solvent at room temperature and 1 mm Hg, the residue, after addition of polymerization inhibitors, is distilled in a thin-layer evaporator at l80°C and 0.5 mm Hg. 200 g of CH. S Λ, ll PCH.CH„OC-C=CH_ / II I (CH3)2CHCH2O 0 CH3 are obtained which corresponds to a yield of 76% of the theoretical yield.

Analysis: found: C 50.0%; Η 7·9Ο%; P 11.3%; S 12.05% calculated:C 50.0%; H 7-95%; P 11.75%; S 12.13%.

EXAMPLE 6 100 g (0.66 mol) of methyl-2-hydroxyethylphosphinic acid ethyl ester, 66.8 g (0.66 mol) of triethylamine and 0,.3 g of phenothiazine are dissolved in a mixture of toluene and methylene chloride, and, with vigorous agitation and cooling, 69 g (0,66 mol) of methacrylic acid chloride are added dropwise. After this addition is complete, agitation is continued for 1 hour, the batch is then cooled to 0°C, and is distilled in vacuo. 116 g of CH. 0 0 Λ ί ll' P - CH. - CH„-O-C-C=CH„ / X Ζ I z CH3 boiling point 147°C at 1.2 mm Hg, are obtained, which corresponds to a yield of 80% of the theoretical yield.

Analysis: found: C 49.2%; H 7.8%; P 14.1% calculated:_9_C 49.1%’; H 7.8%; P 13.9%

Claims (12)

1, A compound of the formula ’-Y-O-C-C=CI1, '2 R. ’3 in which each of R^ and Rg is an alkyl radical haying up to 8 5 carbon atoms; Rg is hydrogen or a methyl radical; X is oxygen or sulfur; and Y is a linear or branched alkylene radical having up to ό carbon atoms.

2. A compound as claimed in claim 1, wherein each of R^ and Rg is an alkyl· radical having from 1 to 4 carbon atoms. 10

3. A compound as claimed in claim 1 or claim 2, wherein Y is an alkylene radical having from 1 to 3 carbon atoms.

4. A process for the preparation of a compound as claimed in claim 1, which comprises reacting an alcohol of the formula P-Y-OH in which R^, Rg, X and Y have the meanings specified in claim 1, with a compound of the formula Z-CO-C=CH, '2 in which Z is a halogen atom, and Rg has the meaning specified in claim 1, in the presence of an inert solvent and in the absence of 20 water.

5. A process as claimed in claim 4 , wherein Z is a chlorine atom

6. A process as claimed in claim 4 or claim 5, wherein the reaction is carried out in the presence of a polymerization inhibitor for the acrylyl or methacrylyl group. 10 41812

7. A process as claimed in any one of claims 4 to 6, wherein the reaction is carried out in the presence of a hydrogen halide-binding compound.

8. A process as claimed in claim 7, wherein the hydrogen halide5 binding compound is a tertiary amine.

9. A process as claimed in any one of claims 4 to 8, wherein the inert solvent is toluene or xylene,

10. A process as claimed in any one of claims 4 to 9> wherein the reaction is carried out at a temperature of from -30 to 10 +100°C.

11. A process as claimed in claim 4 carried out substantially as described in any one of Examples 1 to 6 herein.

12. A compound as claimed in claim 1 whenever prepared by a process as claimed in any one of claims 4 to 11.