DE2031289A1 - Process for the preparation of alpha-isocyanatoalkylarenes with one or more isocyanatoalkyl groups - Google Patents

Description

Imperial Chemical Industries Ltd. London, UK

Process for the preparation of ft-Isocjanatoalkylarenes with one or more isocyanatoalkyl groups.

Priorities * 6/24/1969 and 4/24/1970 - Great Britain

The invention relates to the production of isocyanates from organic halides and to new isocyanates which can be produced by this process.

It is known that isocyanates are thereby produced can that you organic halides containing aliphatically bonded halogen atoms with alkali or alkaline earth Reacts ammonium cyanates at elevated temperatures in the presence of solvents. It is also known that with this Reaction considerable amount of by-products are formed, due to trimerization of the isocyanate, whereby Compounds having an isocyanate ring structure can be obtained. This latter reaction occurs particularly when Organic halides with more than one halogen atom can be used, since such compounds give polyisocyanates which are insoluble under the conditions of the reaction

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- 2 isocyanurate polymers to be polymerized.

It has now been found that a class of organic halides, the isocytes of which are particularly beneficial in the formation of by-products, the yield can be improved considerably if special solvents are used as the solvent for the reaction. The class of isocyanates, to the preparation of which the present invention relates, is formed by those isocyanates which contain an aryl ₉ '&& τ at least by a group of the formula -CBgM (IO, in which each B is independently a hydrogen or © denotes an alkyl group with 1 to M carbon atoms.

So according to the? Req. Proceedings for the production of a-Isocyaaatoalkylar © nea ₉ % aeleSae develop one or more Isocyanatoaili ^ -lgruppen, suggested "which results from the fact that mam an Oi-Halogeaalkylaren with an Allsali, Esdalkali or Ammonium cyanate is converted into a solvent mixture at elevated temperature, which consists of a solvent of high polarity and a solvent of low polarity.

Examples of a ~ Hälogeaallylarea © ₉ di © used in the method according to the invention wer & aa kössa®n _s sisd those of the general Foni @ l £.

Aren

where η is an integer from 1 to 4, -each -E independently Hydrogen or an alcohol soup 1 ^ iS 4 Means carbon atoms and the BsuLogenatom example wise is chlorine or bromine.

008883/2258

BATH

The arene or aryl group can, for example, consist of one, benzene ring, of two benzene rings, which go through. Sulfur, oxygen, a direct bond or a group of the formula C _n E ₂ - (where a is 1 to 6) from HaphtbyI. Anthracenyl, rienanthryl or pluorenyl * Each of the above arene or Iryl groups can optionally be substituted by at least one of the following substituents: the halogen atoms fluorine, chlorine, bromine or iodine, alkyl groups with 1 to 20 carbon atoms, alkoxy groups with 1 to 4 Carbon atoms or 1, ^ J-alkenyl groups which form a further ring with the aryl group, such as in tetralin.

Examples of ^ -Balogenalkylarenes, which can be used in the process according to the invention, are:

2,5-diaethyl-p-xylylene dichloride, 2,5 ~ bimethyl-p-3ylylene-dibromide, 2,3 »5,6-Tetra» ethyl-p-xylylene- <licnlorid,

9,10-bis (chloromethyl) -1,2,3,4 ·, 5 »6,7,8-octahydroanthracene,

p-iylylene dichloride,

Benzyl chloride, Benxyl bromide,

1,4-bis-chloromethyl-naphthalene, 1 _t 4-Bie- (a-chloroethyl) -benxol, ^/ 1,3-Bia- (a-chloro & thyl) -beneol, m-j ^ ylylene dichloride, m-xylylene dibromide, 4-methyl-methylene-dichloride, 4-itbyl-m-jgrlylene-dichloride, 4,5-dimethyl-m-xylene dichloride, 4,6-dimethyl-B-xylylene dichloride, 2,4,5-trimethyl - ^ - sylylene dichloride,

009883/225

BATH ORIGINAL

2,4,6-trimethyl-m-xylylene dichloride, 2,4,5 »e-tetramethyl-m-xylylene dichloride, 4-methyl-benzyl chloride, 4-buty 1-benzylchloride, 4-dodecylbenzyl chloride,

4-metb.yl-6-ethyl-m-xylylene dichloride, 2-methyl-5-ethyl-m-xylylene dichloride, 1.3 »5 ~ tris (cliloromethyl) -2.4 _i 6 ^; -tf ime thy! benzene, 1,3 »5-l3? is- (cliloromethyl) -m-xylene, 4-Μβ thoxybenzylchloride, 4-methoxy-m-xylylene dichloride

»3» 5-Tr ^> is (chloromethyl) -2-methoxy-4,6-dimethyl benzene

2,4-bis (chloromethyl) -1-methyl-oxy-3 »5-dimethylbenzene, 3-chlorobenzyl chloride, 4-chlorobenzyl chloride, 3 ^ -diclilorobenzyl chloride, 5-chloro-m-xylylene-dicloride, 2-methyl -5-chloΓO-πι-xylylene-dxchlorid, 1-chloromethylnaphthalene, 2-chloromethylnapb.thalin, 2,6-bis- (chloromethyl) naphtb.alin, 1-chloromethyl-tetralin, 1,3-bis- (chloromethyl) tetralin _t 1,4-bis (p-chloromethyl) butane, 9,1O-bis (chloromethyl) anthracene, 4,4'-bis (chloromethyl) diphenyl, 4,4'-bis (chloromethyl) diphenyl methane 4 , 4'-bis (chloromethyl) diphenyl ether 2,4,4'-tris (chloromethyl) dipheny1

Preferred α-haloalkylarenes for use in er inventive method are those in which the

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Arene or aryl nucleus is a benzene ring * Particularly preferred are those compounds in which the benzoline
ring! at least one o-position to each group of the formula -OEgHalogen is substituted by an alkyl group, for example methyl or ethyl, and in which B is hydrogen and the halogen is chlorine. Such starting materials are easily obtained by the chloromethylation of alkylated benzenes »

The invention is particularly suitable for the production of Isocyanates in which η is 1, 2 or 3.

Alkali, alkaline earth and ammonium cyanates in the invention Processes that can be used are, for example, the cyanates of lithium, sodium, potassium, magnesium, calcium, Strontium, barium and the ammonium ion. They also include the cyanates of substituted ammonium ions, such as for Example methylammonium, dimethylammonium, trimethylammonium and triethylammonium cyanate. The cyanate is preferred used in a finely divided form.

It should be noted that when the invention Process used solvents against isocyanate groups, inorganic cyanates, and organic halides should be inert under the reaction conditions.

A wide range of high and low polarity solvents can be used in the process of the present invention. The amount of the high polarity solvent can be small, as little as 0.1 % of the total amount of solvent. Normally, mixtures of solvents containing 0.1 to 80% by volume of solution are used.

00988372258

medium high polarity and 99.9 to 20 vol .- # solvent low polarity included.

By the term "high polarity solvent" is meant a solvent meant with a dielectric constant greater than 15. Similarly, ax is the term "solvent low polarity "a solvent with a dielectric constant meant by less than 15.

Solvents of low polarity _f which can be used in the process according to the invention, sis-d for example carbon

aromatic® "Hydrogen, halogenated «/ hydrocarbons, ethers and Ester.

Special example © for solvents of low polarity. are: allphatic, cycloaliphatic, aromatic, and araliphatic hydrocarbons, such as benzene »O) QlUOl, lylene, diethyl benzene, isopropyl benzene, ethylnaph». Thalin, octane, petroleum ether, Cyclohsxaa nmd Methylcyclohe- xan, halogenated aromatic Kohlenwasserstoffβ as sum example monochlorobenzene _β the BichloroTbenzole and Trichlorobensole, ethers, such as BiäthyläthBr "ad Dibutylätherj esters, such as Ithylacetat, butyl 'acetate, Äthosyäthylacetat and Dimethylplithalat.

Preferred low polarity solvents are hydrocarbons and the halogenated ones fabrics.

Lösungemittel high polarity SICAE DL® suitable _β are ana example of the laide carbamates _s ketones, sulfoxides, SnIfon © _t Barnstoff phoraiwide, carbonates, nitriles, HITRO ¥ EaeI "daa in gemäSea retracts,

009883 / 22S8

- 7 - Esters of phosphonic acid.

Specific examples of polar solvents are: dimethylformamide, dirnetbylacetamide, N-methylpyrrolidone, N-methylacetamide, dietaryformamide, diisopropylformamide, diphenylformamide, methyl-ethyl-formamide, ethyl-ethyl-acetamide, dicyclohexyl-acetamide, ethyl-cyclohexyl-acetamide, ethyl-cyclohexyl-acetamide, acetamide, N-isopropylpyrrolidone, N-methylpiperidone, N-methyl-caprolactam, ethyl-N, N ~ dimethyl-carbamate, methyl-HiN-diethyl-carbamate, N-carbomethoxypiperidine, dimethyl sulfone, tetramethylene sulf on, pentamethylene sulfone, methyl ethyl sulfone, methyl cyclohexylsulfon, methyl benzyl sulfone, methyl phenyl sulfone, diphenyl sulfone, TetramethylharnBtof £, hexamethyl-phosphoramld, ethylene and propylene carbonate, acetonitrile, propionitrile, Beneonitril, 3- Methoxy-propioiiitril, Cyclohexanenitril, Succinonitril, Adiponitril, Kitrobensol, the Nitrotoluenes, Nitromethane, Hitroethane, Hitropropane and the Dimethylester Methylphosphonsäure

Preferred solvents of high polarity are amides and in particular dimethylformamide and dimethylacetamide.

Like all reactions using isocyanates, the present process is also carried out under largely anhydrous conditions with the exclusion of water or steam carried out · If desired, an inert gas atmosphere be used.

The reaction is conveniently carried out at atmospheric Pressure and carried out at elevated temperatures of 20 to 25O ° O, although temperatures outside of this range can be used.

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A preferred reaction temperature did 50 to 160 ⁰ oo ^ -Halogenalkylaren and öyanat be heated together in the mixed solvent, wherein the required Erhitzungazeit largely depends on the particular compounds and the temperature used.

Ee is at least a molar fraction of the cyanate for any mobile halogen atom in the o-haloalkylarene is used. The cyanate is preferably used in excess.

The reaction can be carried out in the presence of catalysts. Examples are copper and copper salts, quaternary asmonium salts, especially the bromides and iodides aovie the iodides of alkali and alkaline earth metals

The amount of catalyst used is normally from 0.01 to 5% by weight based on the haloalkylarene. It quantities outside this limit can also be used.

Preferred catalysts are iodine, bromine, the iodine chlorides,

such as honochloride and trichloride,

or mixtures of such catalysts. Iodine or iodine monochloride are particularly preferred.

In order to avoid or reduce product loss, especially during the isolation of the product, it is advisable to add a small amount of acid to the reaction mixture is added. You acid can de reaction participants be added at the beginning of the reaction or sometime later before isolation.

009883/2258

Examples of acids that can be used are mineral acids and organic sulfonic acids »as in the example Metaphosphoric acid, p-toluene sulphonic acid, orthophosphoric acid, methanesulfonic acid, sulfuric acid, hydrogen chloride and JPluoboric acid.

The method according to the invention can be used to to produce a wide range of isocyanates and polyisocyanates, both known and new compounds «

Examples of isocyanates that can be produced by the process according to the invention are!

4-methyl ~ m-3qsrlylene diisocyanate, 4,6-dimethyl-m-xylylene diisocyanate, 2,4,6-trimethyl-m-xylylene diisoeyanate, 2, 4, 6- £ ris (isocyanatomethyl) -m-acylol, 2,4,6-tris (isocyanatomethyl) -1,2,5-trimethylbenzene, 4-chloro-o-xylylene diisocyanate,

4,5- "dichloro-o-xylylene disocyanate,.

3,4,5,6-tetramethyl-o-xylylene diisocyanate, o-xylylene diisocyanate,

5-methyl-m-xylylene diisocyanate, 2,5-dimethyl-m-xylylene diisocyanate, 4-jS.thyl-m-xylyl en-dl isocyanate,

4-isopropyl-m-xylylene-diiooyanate, 2-methyl-5-ethyl-m-xylylβn-diisocyanate, 2-ifethyl-5-isopropyl-m-aylylene-diisooyanate, 5-chloro-m -: ^ lylene-dii8ocyanate, 2-ίfethyl-5-chloro-'m-xylylβn-diisocyalιat _$ 4-Uetho3cy-m-3qsrlylen-diisocyanate

009883/2258

2-metho ^ -5-methyl-m-xylylene diisocyanate, 2, J-dimethyl-p-xylylene diocyanate, 2,3,5 »e ^ tetramethyl-p-ocylylene-diisoeyanat,

9 »10-bis (ieocyanatomethyl) -1» 2,3,4,516.7 »8-octahydroanthracene

p-xylylene diisocyanate, benzyl iocyanate,
m-xylylene diisocyanate, 1,4-bis (isocyanatomethyl) naphthalene, 1,4-bis ((t-isocyanatoethyl) benzene, 4,5-dimethyl-m-xylylene diisocyanate, 2,4 , 5-Tr imethyl-m-xylylene-diisocyaae.t, 2,4,5,6-tetramethyl-ii-xylylene-dtisocyiLaat, 4-methyl-benzyl-isocyanate, 4-butyl-benzyl-iaocyanate, 4-dodecyl- benzyl isocyanate, _{2-methyl-4-ethyl-benzyl-4-v} ieocyanat ifethyl-6-ethyl-m-3Qrlylen-diiso © _t Yanat 1,3,5-tris (isocyanatome thyl) -m-asylol 4-Metho2y benzyl i8ocyanate,

1.3 »5 ~ 3! Ris C isocyanatomethyl) -2-m®thoaQT-4, .e ^ dimethyl-benzene, I 2,4-BiB- (isocyana torn © thyl) -1-methosy-3 5-dimetlayl-feeii20l, 3-chlorobanzyl isocyanate, 4-chlorobenzyl isocyanate, 3 ^ -dichlorobenzyl isocyanate, 1 ^

2,6-bis (ieocyanatomethyl) -aaphth & liia _s 1-isocyanatoiaethyl-tetralia, 1,3 "bis- (isoeyaaatofiietliji) -t @ traIiii ₉ 1,4-bie- (p-ieocyanatomethylplieiiyl) -butane 9,10-bie -'Cisocyaziatomethjl) ° »a2itlirac @ n _f

0098Θ3 / 2258

4,4'-bis (isocyanatomethyl) -diphenylmethane, / 4,4'-bis-iieocyanatometl ^ l) -diphenylether and 2,4,4 '-Tris (iaocyanatomethyl) -diphenyl.

The isocyanates made by the present process can be used to make monomeric, oligomeric, and polymeric ureas and urethanes by known methods. The ones that two or contain more Ieocyanate groups, are particularly useful for the production of polyurethanes, which in turn are sur Production of surface coverings, adhesives, solid Can use urethane rubber materials, fibers and foams

The invention is illustrated by the following examples

explains in more detail where mile skins and percentages are in

Are expressed by weight, unless otherwise stated

In certain examples, a small "tight" becomes an inert one Compound, such as "for example n-octadecane, used" This Compound serves only as an internal standard for gas chromatography (V.P.C.)

example 1

A mixture of 11.6 parts of bis (chloromethyl) durol, 7.3 parts of Hatrlumcyanat, 44 parts of xylene, 47 parts of H, H-dimethylacetamide and 0.3 part of iodine was stirred at the reflux temperature under a nitrogen atmosphere. After 30 minutes gas chromatography showed complete conversion to bis (ieocyanatomethyl) durol. The reaction mixture was ^{filtered at 30 °} C. and 0.3 part of metaphosphoric acid was added. The solvent was removed from the filtrate

009883/2258

distilled off, leaving a residue of crude DiiBocyanät stayed behind. Hächdem the product for the separation of un ~ soluble materials * gave a Crystallization bis (i8ocanatom6thyi) durol with one unit of 96%, which is just a characteristic peak. showed on the gas chromatogram.

Example 2

A mixture of 10 »9 parts of bis (chloromethyl) mesitylene _t 7.3 parts of liatric cyanate, 4? Parts of Ν, Ν-dimethylacetamide, 55 parts of monochlorobenzene and 0.3 part of iodine were stirred at the reflux temperature for 30 minutes under nitrogen, whereupon gas chromatography showed that the starting material had completely reacted. The reaction mixture was filtered and 0.3 part of metaphosphoric acid was added. The solvent was evaporated from the piltrate under reduced pressure, leaving a residue from the crude isocyanate. Distillation gave bis (isocyanatomethyl) mesitylene as a viscous oil which crystallized on standing,

Kp 132-4 ° 0/35 mm.

Example 3
A mixture of 12.8 parts of benzyl chloride, 9.5 parts of potassium cyanate, 50 parts by volume of monochlorobenzene, 50 parts by volume of !!, H-dimethylacetamide, 2.4 parts of n-octadecane (internal VPC standard) and 0.3 Parts of iodine were stirred at the reflux temperature under a nitrogen atmosphere. After 30 minutes, gas chromatography indicated complete completion of the reaction, benzyl isocyanate having been obtained in an estimated yield of 55%. Addition of aniline, subsequent filtration and subsequent evaporation of the solvent from the filtrates gave a solid material which was identified as crude K'-benzyl-N-phenyl urea.

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The procedure was repeated, except that the 2! F, N-dimethylacetamide by an equivalent volume of monochlorobenzene * was set. After 30 minutes, gas chromatography showed a single undiminished peak which can be assigned to benzyl chloride.

Example 4

A mixture of 11.6 parts bis (chlaromethyl) durol, 7.3 Parts sodium cyanate, 5pVol, -part monochlorobenzene, 5OVbl »- Parts of H ^ N-dimethylacetamide, 1.0 part of n-octadecane (inner V.P.C. standard), approximately 0.5 part phosphorus pentoacid and 0.3 part of iodine was stirred at the reflux temperature under a nitrogen atmosphere. After 35 minutes, gas chromatography showed that the reaction was over and that bis (isocyanatomethyl) durol in an estimated yield of $ 87 had been received. Similar preparations in which the N, N-dimethyl acetamide is replaced by a different solvent are shown in Table I.

Table X

E.g. solvent solvent Eeak- Beak T.P.O.- component 1 component 2 functional functional Analysis on temp. Time Until (ieocyana- ( ⁰ G) (min) tomethyl; du-
rol 1 MOB N-methyl 155 30th 77% yield pyrrolidone 2 MOB SuIfolan 150 180 $ 57 yield 3 MOB Amyl acetate 155 45 track 4th MOB Hexamethyl phosphoramide 140- 15th 64% yield 150

(MCB »Monochlorobenzene) Experiment 3 does not explain the invention but is

009883/2258

a comparison experiment.

example 5

A mixture of 11.6 ropes of bis (chloromethyl) durolt 9 »O parts of potassium cyanate, 50% parts of conochlorobenzene, 50%
VoX. »Parts of N, N-dimethylacetamide, 2.4 parts of octadecane and 0.3 part of iodine were stirred under nitrogen at reflux temperature. To. For 15 minutes, gas chromatography showed complete conversion, with bis (isocyanatomethyl) durol

in an estimated yield of $ 89. w

Similar experiments were carried out in which the monochlorobenzene and the Η, ΐ-Bimothylaeetaiild individually or
both have been replaced with other solvents as shown in Table II below.

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E.g. Solvent (100) (100) Table II Reaction JHeaction ( ⁰ C) (time (min) ■ 30th . ι ■ component 1 Dimethyl ether of Dimethyl acetamide temperature ΐ ^^ j
VPC analysis on i 88 % (50) (100) solvent 15th Bis (isocyanate- |
methyl) durol A. Monochlorobenzene Dimethyl ether of component 2 147 80 % (50) (50) (50) 20th > 70 % B. - ditto - Butyl acetate Dimethyl sulfone 150 70 % J. (50) (70) (50) ■ 40 46 36 O C. - ditto - - ditto - Tr ime thylpho sphat 138 5 O
(O (50) 39% 00 Dreary thylpho a- 60 OO D. phonate 159 co 180 0 ro Diethylene glycol 90 ro 0. cn P. Ethylene glycol 137 UV (50) Dimethylacetamide 135 (30) H - ditto, - 150

The quantities of the individual solvents relate to the volume, with the exception of the °

Try A _f where they relate to weight. _ *

. '. ■. ■■■■■ '■' ■. ro

- 16 -

Example 6

A mixture of 11.6 parts of BisCchloroiaeth2 ^r l) durol _f 7.3 parts of sodium yanate, 90 parts of mono-chlorobenzene, 10 parts of ΪΓ, Ν-dimethyl acetamide and 0.3 parts iodine was stirred at the reflux temperature under a nitrogen atmosphere. After 24-0 min, VoP.C. a main peak, which could be assigned to bis (isocyanatomethyl) durol, and smaller peaks, which could be assigned to bis (chloromethyl) durovl · and chloromethylisocyanatomethyldurol »The estimated yield of bis-isocyanatometliyDdiirol. was y \% » The following examples of Table III show the influence of the change in the ratio and the nature of the solvent components.

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BATH ORIGINAL

• - E.g. Table III Solvent (a) Reaction 51 # 0 approx V * P.O. -Analysis action ro Component 1 Component 2 time (min) approx
10056 Yield of BIMD temperature ( ^p C) 0
co 0 Monoohloror- Pisiethylacet- Traces of BCMD ro benzene amide 0 considerable men CD 90 10 240 approx ge to mono 133 co 1 75 25 105 95% Onloroethyldurol- 136 «Ι»> approx species are off 2 Π being 50 5p 15th 84% 143 3
■ Xylene. "
50 " 10 M. 143 4th ■
Xylene ... " • 009 50 50 20th Il 145 ο »
OO 5 Xylene dimethylform * Sw 50 amide ₅₀ 20th '. ■ It 137 N>
PO 6th Butyl acetate OI
00 100 150 126 7th Oellosoive- acetate ~ 100 80 It 154 8a Butyl acetate dimethylacetate
Γ 95 amide 65 η 125

8b 9
ι 95 15 30th <Λ% smaller amount of ac
σΐ-Μοηο 125 C. 95 25 4-5 20 % increased length 125 Cyclohexanone
1.00 60 28 % Mainly mono
and smaller amount
BCMDanvesend 154

o> fs)

CT! OO

BIMD «> = Bie (isocyanatoethyl) durol BCMD «Bis (chlorom · thyDdtirol Mono «chloromethyliaocyanatomethyldurol (a) = parts by volume

tsj OO CD

Example 7

A mixture of 20.7 parts of bis (iodomethyl) durol, 90 parts of potassium cyanate, 75 ^ ⁰¹ parts of monochlorobenzene, 75 parts by volume of Ν, Η-dime-ghylacetamide and 3 parts of n-octadecane (internal VPC standard) was stirred at reflux temperature under nitrogen. After a reaction time of Ί20 min, VPO showed a single peak, which can be assigned to bis (isocyanatomethyl) durol, and an estimated yield of 64%. The reaction mixture was filtered hot to remove insolubles and analysis of the filtrate showed a 58% yield of bis (isocyanatomethyl) durene. Addition of cyclohexane to the piled steps and allowing to stand gave 6.7 parts of a deposit of pale cream needle-like crystals identified by infrared spectroscopy as bis (isocyanatomethyl) durene; Yield 55 wt. #.

A similar reaction carried out in 150 parts of monochlorobenzene ^ < gave negligible amounts of isocyanate.

The raw material, which has largely been recovered, was the only identifiable substance.

At game 8

A mixture of 16.1 parts of 4-chlorobenzyl chloride, 9 * 0 parts potassium cyanate, 75V0I. parts white spirit, 50VoI, parts by petroleum ether? (S'raktion 100-120 ⁰ C) 15Vol.-5 eiieii dimethylacetamide, 2,4 Parts of n-octadecane (7th PC internal standard), 0.5 part of iodine and 0.1 part of phosphorus pentoxide were stirred at the reflux temperature under a nitrogen atmosphere. The course of the reaction was monitored by VPC. Samples taken within the first 35 minutes showed only a single peak that could be attributed to the starting material. 10 parts of 8JJ -?) Iinethylacetamide were then added. Each one more

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Heating for 45 minutes was performed by gas / liquid chromatography found a faint second peak that was assigned to 4-chlorobenzyl isocyanate. The estimated Yield was few? than 2% «, another 20 parts of H, N-dimethylacetamide were admitted. Gas / Ilüssig otromatography within the next 85 minutes showed a considerable Increase in the amount of isocyanate formed.

Example 9

A mix of 13 »3 parts. 2,4,6-tri8 (chloromethyl) mesitylene, 11 Parts of sodium cyanate, 50 parts of H, N-dimethylacetamide, 30 pieces of white gasoline, 40 parts of petroleum ether (Bp 100-120 ° C), 2.4 parts of n-octadecane, 0.5 part of phosphorus pentoxide and 0.3 part of iodine was stirred and refluxed under nitrogen for 90 minutes. Gas chromatography showed that no further reaction had occurred »Petroleum ether and ΙΤ, Η-dimethylacetamide were through codistillation removed with another 150 parts of white fuel. 100 parts of hot toluene were added to the resulting hot mixture. Bach filtration of the solid residue the filtrate was evaporated to a small volume. When the filtrate cooled, a precipitate formed which are filtered off and placed in a vacuum desiccator a pressure of 15 mm of mercury and about 20 ° ö dried / The product obtained in this way contained 29.4% by weight of isocyanate groups. The theoretical value for 2,4,6-tris (isocyanatomethyl) mesitylene is 44.2%. test of the product by gas chromatography showed only the triisocyanate, white spirits and n-octadecane, the the latter substance was present in sufficient quantity that it was responsible for the reduced isocyanate value could be made.

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Claims (11)

Claims Process for the preparation of α-isocyanate oallcylarenes, which contain one or more isocyanate groups, characterized in that an a-haloalkylarene - with a Reacts alkali, alkaline earth or ammonium cyanate at elevated temperature in a solvent mixture, daa contains a high polarity solvent and a low polarity solvent. 2. The method according to claim 1, characterized in that the CL-haloalkylarene has an arene nucleus which is a benzene ring. 3 * Method according to claim 2, characterized in that the benzene ring in at least one o-position to one each ο, -haloalkyl group is substituted by an alkyl group and that the Or-haloalkyl groups are chloromethyl groups are. 4. The method according to any one of the preceding claims, characterized in that the α-haloalkylarene 1,2 or contains 5 O ^ -haloalkyl groups 5. The method according to any one of the preceding claims, characterized in that the solvent is of low polarity a hydrocarbon or halogenated carbon is hydrogen. 6. The method according to any one of the preceding claims, characterized characterized in that the high polarity solvent is an amide. 009883/2258 -2Z- 7. The method according to claim 6, characterized in that the amide is dimethylformamide or dimethylacetamide » 8. The method according to any one of the preceding claims »characterized in that the reactants together to a temperature of 50 to 16 (A; are heated« 9 · Method according to one of the preceding claims, characterized characterized in that a catalyst is used. 10. The method according to spoke 9 $ characterized in that daS as a catalyst iodine or Joaaon.ocM.orid vewfeadet w5.rd · 11. The method according to any one of the preceding claims, characterized in that the reaction participants before the isolation of the product will sugasetst an acid » 12 »α-isocyanatoalkylmesitylenes, the 1,2 or 3 α-isocyanatoalkyl groups contain" ψ 13. 2,4,6-Tris (isocyanatom @ thyl) ®esityl © B _t »14, 2,4-bis (isocyanat © metliyl) m®sityl®n · 009883/2258