DE2839084A1 - Tri:allyl-isocyanurate prepn. under anhydrous conditions - by reacting alkali cyanate with allyl halide in an aprotic polar solvent, used e.g. for prodn. of synthetic resins and synthetic rubber - Google Patents

Abstract

Tri-(allylisocyanurate), (I) is prepd. by charging an alkali cyanate and an aprotic polar solvent to a reactor and extracting water by distn. before adding the allyl halide, pref. to the liq. phase of the reaction zone. After completing the reaction, the solvent is distilled off from the reaction soln. Water or an aq. HCl soln. is then added and the formed (I)-contg. layer is sepd. from the aq. layer. (I) is a raw material and intermediate for the prodn. of synthetic resins, synthetic rubber and other organic chemicals. Side-reactions, caused by presence of water in reaction system, are prevented. (I) is obtd. quickly, in high yields, by increasing allyl halide concn. in liq. phase of reaction zone. The reaction prods. and the polar solvent can be recovered separately in good yields.

Description

description

The invention relates to an improved method of manufacture of tri- (allyl isocyanurate) by reacting an allyl halide with an alkali cyanate.

Tri- (allyl isocyanate) is used as a starting material and as an intermediate in the industry for the production of synthetic resins, synthetic rubber and other organic chemicals are useful.

There is already a process for making tri- (allyl isocyanurate) by reacting an alkali metal cyanate with an allyl halide in an aprotic one known polar solvents.

This method is in the published Japanese patent application No. 3985/1961.

This process produces allyl isocyanate as an intermediate, which then trimerizes in the same reaction system to form tri- (allyl isocyanurate) becomes, as shown in equations (1) and (2): CH2 = CHCH2X + MeOCN e CH2 = CHCH2NCO + MeX (1) 3CH2 = CHCH2NCO # (CH2 = CHCH2NCO) 3 .............. (2).

In these, X is a halogen atom and Me is an alkali metal.

The known processes for the preparation of tri- (allyl isocyanurate) such as that described in Japanese Patent Application have various Disadvantage.

When water exists in the reaction system, side reactions occur as shown in equations (3), (4) and (5). You decrease the yield of tri- (allyl isocyanurate) is significant.

2CH2 = CHCH2NCO + 1120 # CH2 = CHCH2NHCONHCH2CH = CH2 + Co2 ... (3) C112 = Cl1CII2X + H20 - + CH2 = CHCH20H + HX ................ (4) CH2 = C1lCII2NCO + CH2 = CHCH2OH # CH2 = CH2 = CHCH2NHCOOCH2CH = CH2 (5) In these, X in turn denotes a halogen atom and Me denotes an alkali metal. Of the Water content in the reaction system hinders the formation of the tri- (allyl isocyanurate) essential, e.g. through the hydrolysis of the aprotic solvents used as solvents polar compound, in addition to the side reactions listed above (3), (4) and (5). The presence of water in the reaction system should therefore as much as possible be avoided. The aprotic polar ones used as reaction solvents Compounds such as dimethylformamide and dimethyl sulfoxide and the starting material However, the alkali metal cyanates used are highly hygroscopic and their technical products contain a lot of water. The removal of the water is However not easy.

In addition, the boiling point of the allyl halide (most allyl halides boiling below 1030 C) is lower than the reaction temperature (above about 1100 C), so that both the allyl halide supplied as starting material and the through Allyl halide returned to the reaction zone at the surface of the reflux Evaporation of the reaction zone. In the known processes, the allyl halide becomes fed to the surface of the reaction zone, either all at once or dropwise, wherein the allyl halide evaporated as the reaction proceeds returns.

Since in this reaction the allyl halide on the surface of the reaction zone evaporated, the concentration of allyl halide in the reaction zone becomes substantial reduces and requires a high capacity reflux condenser, as well as a repeated one Long-term reflux. However, these long reaction times cause decomposition of the allyl halide with accompanying side reactions.

It is true that there is still a procedure for carrying out the implementation under pressure known to the concentration of the allyl halide in to increase the reaction zone. However, this procedure leads to an increased Formation of resinous by-products and a reduction in the yield of tri- (allyl isocyanurate), although the reason for this is not clear.

Another disadvantage of the known method is that the Reaction products and the solvent are not obtained separately from the reaction system after the implementation is complete.

The allyl halide alkali cyanate reaction system forms due to the Presence of salts as by-products creates a slurry.

For obtaining the tri- (allylcyanurate) as a reaction product various salt removal methods known, such as suction, pressure filtration, centrifugal separation and the like.

However, these salt removal methods result in a large loss of reaction products and solvents, as the reaction products contained in the salts and solvents are separated and removed along with them. To this one To avoid loss, the salts must be washed with a solvent and that Solvents contained in the salts have to be obtained, etc., which is often too technical Disadvantages. Another known method of removing the salts is in a washing process with water, in which the salts through the direct Encore of water to be dissolved to the slurry after the completion of the reaction. But this process also causes a large loss of reaction products, the are dissolved in the water-solvent system and raises the difficult problem of Separation of the aqueous phase from the reaction products, for which an additional one Extraction solvent is required. Filtration of the slurry after Completion of the reaction requires an aprotic polar solvent for the Wash the filter cake (salts), and as the salts are in this solvent The salts that dissolve after the extraction of the solvent must also dissolve substantially be removed. The mere fractional distillation of the slurry after completion of the reaction and the purification of the tri- (allyl isocyanurate) is difficult because of 1,3-diallylurea, diallyl carbonate, allyl-N-allyl carbmate and the like are formed as by-products of the reaction and in the tri- (allyl isocyanurate) Fraction are included.

The known processes for the preparation of tri- (allyl isocyanurate) are thus neither in terms of purity nor the yield of the desired product satisfactory.

The invention relates accordingly to an improved method for Production of tri- (allyl isocyanurate) and especially the distance of water, which has a detrimental effect on the conversion to the production of tri- (allyl isocyanurate) affects.

The invention also relates to the preparation of tri- (allyl isocyanurate) in a short time and in good yield by increasing the allyl halide concentration in the liquid phase of the reaction zone.

Furthermore, according to the invention, the reaction products and the aprotic polar solvents recovered separately in good yields after the reaction for the preparation of the tri- (allyl isocyanurate) has ended.

The inventive method for the preparation of tri- (allyl isocyanurate) by reacting an allyl halide with an alkali metal cyanate in an aprotic one polar solvent is characterized in that the solvent and introduces the alkali metal cyanate into a reaction vessel and dehydrates it with distillation and then adding an allyl halide. The allyl halide will go into the liquid phase introduced into the reaction zone, furthermore, after the reaction has ended, the solvent is added removed by distillation, water or an aqueous hydrogen chloride solution to added to the reaction mixture and the formed, the Tri- (allyl isocyanurate) containing layer separated from the aqueous layer.

The first improvement of the method according to the invention consists in that the aprotic polar solvent and the alkali metal cyanate by distillation be dewatered, either by the fact that the solvent and the alkali metal cyanate added to the reaction vessel and then the solvent partially under atmospheric pressure or reduced pressure is distilled off, thereby the water together with removing the solvent, or by adding an organic solvent such as Benzene, toluene, xylene, the opposite of the reaction solvent, the starting materials and the intermediate products of the reaction are inert and are azeotropic with water Mixture forms, adds, so that in the reaction solvent and in the alkali metal cyanate contained water together with the organic solvent by azeotropic distillation to remove.

Since according to the invention the for the formation of the tri- (allyl isocyanurate) detrimental content of water is removed before the reaction can be detrimental Side reactions and the hydrolysis of the solvent are prevented. The second Improvement of the process according to the invention is that the allyl halide is introduced directly into the liquid phase of the reaction zone, so as to Allyl Halide Concentration increase in the liquid phase.

The introduction of the AiJylhalogenids can be effected in that the alkali metal cyanate is mixed with the aprotic polar solvent beforehand, the temperature of the mixture formed is increased to the reaction temperature and then the allyl halide through a suitable tube reaching into the liquid phase or through an inlet on the side wall of the reaction vessel. The entire Allyl halide evaporating during the reaction is passed through a reflux condenser cooled and condensed and then again through the Einleitunysrohr or through the Inlet introduced. Every pipe and every inlet is suitable as long as it has the direct introduction of the gaseous allyl halide into the liquid phase of the reaction zone enables.

The allyl halide can be introduced in any manner, e.g. at the push of a button, by introducing it together with an inert gas, e.g. nitrogen, by pumping in and the like.

The direct introduction of the starting allyl halide or the recycled one Allyl halide in the liquid phase of the reaction zone leads to a considerable Reduction of the reaction time, to an increase in the yield of tri- (allyl isocyanurate) and substantial control over the occurrence of side reactions in comparison to the known processes in which the Allyl halide to the Surface of the liquid phase is dripped.

According to the third improvement of the method according to the invention after the reaction has ended, the solvent is removed from the solution by distillation removed to recover the reaction products and the solvent separately.

The distillation of the solvent can be carried out under atmospheric pressure or take place under reduced pressure, with a stirring process or something else Mixing must be taken into account as the system forms a slurry and the viscosity of the slurry increases towards the end of the distillation.

Then water or an aqueous hydrochloric acid solution is added to a Tri (allyl isocyanurate) layer and an aqueous layer.

The formation of the tri- (allyl isocyanurate) layer and the aqueous layer requires a temperature at which the tri- (allyl isocyanurate) becomes a solution form is melted. This temperature can be relatively low if a large amount of the aprotic polar solvent remained. she should however, it can be relatively high if the retained amount is this Solvent (il S is low. The temperature is usually above about 15 ° C, preferably above 20 ° C and especially above 30 ° C.

The amount of water or necessary for the formation of the aqueous layer the aqueous hydrogen chloride solutions must be sufficient to remove those formed during the reaction Dissolve salts.

It is known to be a salt of a metal that belongs to group II of the periodic table belongs to use if a large amount of alkali metal carbonate is contained in the starting alkali metal cyanate See Published Japanese Patent Application No. 26766/1967. Since that Carbonate of the Group II metal remains, except for the aforementioned salts, In this case, the use of the aqueous hydrochloric acid solution causes the solution. While the salt solution in the water is basic and the one in the aqueous hydrochloric acid solution is acidic, is the tri- (allyl isocyanurate) under both basic and acidic conditions resistant.

The temperature of the water used in the process of the invention or the aqueous hydrochloric acid solution is preferably above 23 ° C. and in particular above 300 C up to the boiling point, so that no crystallization of the tri- (allyl isocyanurate) occurs. A higher temperature is effective when by-products are in large quantity are present that are to be resolved. The amount used is accordingly Water or the aqueous Hydrogen chloride solution sufficient if the salts are dissolved.

The number of times of washing is not particularly limited.

The tri- (allyl isocyanurate) layer thus obtained is of high purity and as such can be used for the manufacture of end products or further purified, e.g., by distillation under reduced pressure.

The allyl halides used in the process of the invention include e.g. allyl chloride (CH2 = CHCH2Cl), allyl bromide (CH2 = CHCll2Br), allyl iodide (C112 = C11C112I) and the same.

The alkali cyanates include e.g. Lithium cyanate (LiOCN), sodium cyanate (NaOCN), potassium cyanate (KOCN), calcium cyanate (Ca (OCN) 2), alone or as mixtures of two or more of these cyanates.

The aprotic polar solvents include, for example, dimethylformamide, Dimethyl sulfoxide, acetonitrile, hexamethylphosphamide, N-methylacetamide, tetramethylurea and the same.

In the preparation of the tri- (allyl isocyanurate), alkali iodide and Alkali bromide as a promoter, furthermore a salt of a metal of group II, such as calcium benzoate and calcium acetate as Cocatalyst for the suppression of side reactions be used.

The preferred ratio between these reactants, allyl halide and alkali cyanate, ranges from 0.8 to 5.0 moles of alkali cyanate per mole of allyl halide. The reactants can be used in approximately equimolar amounts if both are of good purity. However, if it is desired, it can be implemented more quickly to finish, one prefers a slight excess of alkali metal cyanate over the theoretical Lot. The reaction goes smoothly using the solvent described above at a temperature between 50 to 2500 C before and in general at a Temperature between 70 and 1500 C. The reaction time depends on the amount and the Type of allyl halide and alkali metal cyanate and cannot generally be predetermined will. Usually it is between 1 and 20 hours. The amount of solvent used is not subject to any particular restrictions and depends on whether with larger or a smaller amount of solvent, the process is difficult or easy and the response time is reduced or lengthened. Preferably it is about one to ten times the amount by weight of the alkali metal cyanate.

Example 1 In a 5 1 reaction vessel, which is equipped with a stirrer, a Thermometer, a tube for the introduction of the allyl halide, the open end of which is at the bottom of the reaction vessel, and a reflux condenser with a pipe for the return the condensed liquid was equipped, the open end of which is also At the bottom of the reaction vessel were 2.0 kg of dimethyl sulfoxide and 1.0 kg Potassium cyanate given with a purity of 98.5%. The contents were stirring heated to 1300 C. Subsequently, 1.2 kg of allybromide was continuously inside 1.5 hours under their egg (J (pressure was introduced under the surface of the liquid. During the introduction of the allyl bromide, the reaction temperature was increased to 120 to Held at 1300 C. The formation of reflux liquid ceased 15 minutes after the introduction of the allyl bromide. The mixture was then stirred at 1300 ° C. for 1 hour, cooled and then centrifuged. The solid material obtained was washed with dimethyl sulfoxide, the washing liquid obtained together with the filtrate obtained during centrifugation and distilled under reduced pressure. After adding water to the distillation residue and stirring the mixture, the deposited aqueous layer was discarded.

The residue became under reduced pressure (123 to 1250 C / 1 mm llg) distilled. 0.79 kg of tri- (allyl isocyanurate) were obtained in a yield of about 95% based on the allyl bromide.

For comparison, an experiment was carried out in a 5 1 reaction vessel, in which the allyl bromide and the reflux liquid do not go below the liquid surface but were added dropwise from the upper part of the reaction vessel. That Dimethyl sulfoxide and the potassium cyanate were heated to 1300 ° C. with stirring, whereupon the allyl bromide was added drop by drop. In this case the amount was educated Reflux liquid larger and it was difficult to keep the reaction temperature above 1200 Hold C.

The dropwise addition of the allyl bromide therefore had to be interrupted frequently so that its addition took about 3 hours. besides, it took time about 1.5 hours after the allyl bromide addition was complete, until the reflux stopped. The same treatment as in Example 1 gave after stirring at 1300 for one hour C 0.69 kg tri- (allylisocyanur.at) in a yield of about 83%, based on the Allyl bromide.

Example 2 In a 1 000 1 reactor equipped in the same way was like that of Example 1, were 400 kg of dimethylformamide, 200 kg of sodium cyanate with a purity of 93%, 8 kg of anhydrous calcium chloride and 1 kg of potassium bromide given. The temperature of the contents of the reactor was heated to 1300 ° C. with stirring. Then 200 kg of allyl chloride were added within 2 hours continually introduced into the reactor under its own pressure.

During this time, the reaction temperature rose to 120-1400 C held. About 30 minutes after the introduction of the allyl chloride, the reflux stopped, essentially on. It was then stirred for 1.5 hours at 1300 C and then chilled. The reaction liquid was centrifuged, the separated solid material washed with dimethylformamide and the washing liquid together with the filtrate, obtained by centrifugation is distilled under reduced pressure to recover the dimethylformamide. 100 were added to the distillation residue kg n-hexane given. It was then filtered and the n-hexane was obtained from the filtrate by distillation removed under reduced pressure.

Distillation under reduced pressure gave (123 to 1250 C / 1mm Hg) based on 203.1 kg of tri- (allyl isocyanurate) in a yield of about 93% on the allyl chloride.

For comparison, the same experiment was carried out in a 1,000 liter reactor, whereby the allyl chloride and the reflux liquid are not below the surface of the liquid, but were dripped in from the upper part of the reactor. It became the same Amounts of starting materials as used above. The contents of the reactor were stirred heated to 1300 C. Then the same amount of allyl chloride was added dropwise. In this case, the amount of reflux liquid was greater and the addition of the Allyl chloride Took about 4.5 hours to keep the reaction temperature above 120 ° C. In addition, it took about 1.5 hours after the addition of the allyl chloride for the Reflux stopped. By heating at 1300 ° C. for 1.5 hours with stirring and more Processing as described above, 183.4 kg of tri- (allyl isocyanurate) were in one Yield of about 84% based on the allyl chloride obtained.

Example 3 10 kg of diethylformamide were placed in a 30 l reaction vessel with a moisture content of 0.12%, 4.5 kg of potassium cyanate with a purity of 94% and a moisture content of 0.3% and 0.3 kg of toluene were introduced. The contents of the reactor were heated to 1100 ° C. with stirring, then 0.15 kg of toluene removed by simple distillation, whereupon the residual moisture in the system is 0.02 % fraud. The residue was then heated to 1200 ° C. in the reactor and within of 3 hours, 4.32 kg of methyl iodide was introduced. The respondents were Stirred at 100 to 1200 ° C. for a further 3 hours. The reaction mixture was then cooled centrifuged, washed the deposited solid material with diethylformamide and the washes were taken along with the filtrate that was removed from centrifugation was obtained under reduced pressure (67 to 690 ° C / 15 mmHg) for recovery of the diethylformamide distilled. The crystals that say goodbye, when the distillation residue was added to water, it was filtered off and removed from methanol recrystallized. 1.54 kg of tri (methyl isocyanurate) with a melting point were obtained from 176 to 1770 C. One carried out without toluene under the same conditions Comparative experiment gave 1.13 kg of tri- (methyl isocyanurate) in a yield of about 65%.

Example 4 In a reaction vessel as in Example 3 were 10 kg of dimethylacetamide with a moisture content of 0.1%, 2.83 kg of potassium cyanate with a purity of 94.5% and a moisture content of 0.2% and 0.1 kg of m-xylene. Of the The contents of the reaction vessel were heated to 1200 ° C. while stirring. Then it became 0.07 kg of m-xylene removed by simple distillation. The residual moisture in the system was then 0.03%. The contents of the reaction vessel were then increased to 1300 C., then 3.7 kg of n-propyl bromide were added over the course of 4 hours.

It was stirred for two hours at the same temperature and then chilled. The reaction mixture was then centrifuged by centrifugation obtained solid material washed with dimethylacetamide and the washing liquids were reduced together with the filtrate obtained by centrifugation under reduced Distilled pressure (83 to 840 C / 32 mm Hg) to recover the dimethylacetamide. To the distillation residue were given water and benzene, and the reaction product was extracted with benzene. After the benzene has been distilled off from the extract, by distillation under reduced pressure, (116 bis 1180 C / 2 mm Hg) 2.4 kg of tri- (n-propyl isocyanurate) in a yield of about 94%, based on the n-propyl bromide.

Example 5 In an 8m³ reactor equipped with a fractionating column 10 perforated floors were equipped, 4,000 kg of dimethylformamide with a Moisture content of 0.6%, 2,000 kg of sodium cyanate with a purity of 85 % and a moisture content of 0.36%, 200 kg of anhydrous calcium chloride and Introduced 10 kg of potassium bromide. The reactor contents were increased to 90 to 950 with stirring C, then 294 kg of dimethylformamide at a pressure of 125 mm Hg and a reflux ratio of 5 at 90 to 950 C distilled off. The residual moisture content in the system it was 0.05%. Then the temperature of the reactor contents increased to 1300 C, and within 2.5 hours 2050 kg of allyl chloride were added. The temperature of the reaction mixture was then kept at 1,300 for a further 1.5 hours C.

The cooled reaction mixture was centrifuged and the deposited solid material washed with dimethylformamide. the Washing liquids were taken for recovery together with the filtrate obtained by centrifugation of the dimethylformamide distilled under reduced pressure. After adding Toluene to the distillation residue and filtering the mixture became toluene distilled off and the distillation residue under reduced pressure (123 to 124 ° C / 1 mm Hg) distilled. 2,104 kg of tri- (allyl cyanurate) were obtained in a yield of about 94% based on the allyl chloride.

A comparative experiment was carried out without distilling off dimethylformamide carried out. 1,455 kg of tri- (allyl isocyanurate) were obtained in a yield of about 65%.

Example 6 In a 1 1 reaction vessel equipped with a stirrer and a Thermometer was fitted with 600 g of tetramethylurea with a moisture content of 0.5%, 85 g of potassium cyanate with a purity of 98.5% and a moisture content of 0.2% and 30 g of benzene were added. The contents of the reaction vessel were added with stirring heated to 800 C1 then 15 g of benzene were removed by simple distillation, whereupon the residual moisture content in the system was 0.02%. The residue was with 137 g sec. Butyl bromide is added and the temperature of the mixture is increased to 130.degree elevated. To effect the reaction, the temperature was kept unchanged at this for 5 hours Value. After cooling the reaction mixture, it was filtered and the deposited Solid washed with tetramethylurea, which drains through molecular sieve 4A had been. The washing liquids were fractionated along with the filtrate distilled, whereupon 72.3 g of tri- (sec-butyl isocyanurate) with a melting point of 100 to 1020 C in a yield of about 73%, based on the sec-butyl bromide.

A comparative experiment was made under the same conditions, however carried out without the addition of benzene. 42.5 g of tri- (sec-butyl isocyanurate) were obtained in a yield of about 43%.

Example 7 In a reaction vessel as in Example 6 was 500 g of dimethyl sulfoxide with a moisture content of 0.2% and 100 g of sodium cyanate with a purity of 94% and a moisture content of 0.1% with stirring. Under 100 g of dimethyl sulfoxide were distilled off under reduced pressure (85 to 870 ° C./25 mm Hg). The residual moisture content in the reaction system was then 0.01%. Then were 151 g of isoamyl bromide was added, and the reaction system was kept under reduced pressure for 20 hours Pressure of 700 mm Hg held at 900 ° C. After cooling, it was filtered and the solid obtained is washed with dimethyl sulfoxide, which is passed through a molecular sieve 4A had been drained. The washes and the filtrate were fractionated distilled, whereupon 72.3 g of tri- (isoamyl isocyanurate) in a yield of about 64% based on the isoamyl bromide received.

For comparison, the above experiment was carried out again, but without distilling off dimethyl sulfoxide. In this case, 40.7 g was obtained Tri- (isoamyl isocyanurate) in a yield of about 36%.

Example 8 150 kg of dimethylformamide, 80 kg of sodium cyanate with 5% by weight of sodium carbonate impurity and 1 kg of potassium bromide introduced, whereupon with heating to 130 ° C and with stirring 76.5 kg of allyl chloride added within 3 hours. After stirring for a further 3 hours at 130 to 1350 C, dimethylformamide was recovered by distillation under reduced pressure. 250 l of water were added to the distillation residue. Then it was on 400 C and stirred for 30 min. The watery layer that separated on standing, was removed and the layer containing the tri (allyl isocyanurate) was removed twice with 100 l of water each Washed at 300 C. After detaching of the water layer, the layer of tri- (allyl isocyanurate) was dehydrated by heating and distilled at 113 to 1150 C / 1 mm lig.

Example 9 150 kg of dimethylformamide, 85 kg of sodium cyanate with 10% by weight of sodium carbonate as an impurity, 5 ky of anhydrous Calcium chloride and 1 kg of potassium bromide were introduced.

The reactor contents were allowed to react as in Example 1, whereupon Recovered dimethylformamide. 250 l of water were then added to the reaction mixture 300 ° C., and then slowly concentrated hydrochloric acid with a stirrer to adjust the pH of the water layer to 4.0. After the reaction mixture has stood the aqueous layer formed was removed and the layer of tri- (allyl isocyanurate) washed twice with 100 l of water at 300 ° C. each time. After the second wash it was neutralized by adding 1N aqueous sodium hydroxide solution, so that the I. Value of the aqueous layer was 7. The aqueous layer was removed and the Layer of tri- (allyl isocyanurate) as in Example 1 to obtain the tri- (allyl isocyanurate) distilled.

Comparative Example 1 The one cooled to room temperature as in Example 1 Reaction mixture 3 was transferred to a 3 m container, whereupon 2,500 l water of 400 ° C. without dimethylformamide having been distilled off. The mixture was then stirred. After it was left to stand and the liquid Hardly parted, 200 liters of toluene was added to the mixture as an extraction solvent given. The mixture was stirred and then to separate the aqueous layer left to stand, from which the dimethylformamide was obtained by distillation. After the toluene was distilled off from the toluene layer, it was obtained by distillation Tri- (allyl isocyanurate). The results obtained are together with those of the examples 1 and 2 and those of Comparative Examples 1 and 2 in Table 1.

Comparative Example 2 That obtained as in Example 2 and brought to room temperature The cooled reaction mixture was centrifuged to remove the solid salts. then the dimethylformamide was obtained by distilling the separated liquid. When the dimethylformamide was distilled off, salts occurred which were in the liquid dissolved again and made the liquid a viscous slurry, which made the separation of the salts by filtration difficult. For dilution were 100 1 toluene Zll added and after filtering the diluted slurry under Toluene was distilled off under pressure. Tri- (allyl isocyanurate) was obtained.

TABLE 1 Example Recovery of Di- Yield Tri- + Purity of methylformamide,% (allyl isocyanurate) Tri- (allyl% isocyanurate),% Example 1 98.5 92.0 99.1 Example 2 98.0 93.3 99.3 Comparative Example 1 72.3 91.5 97.8 Comparative Example 2 87.1 83.0 97.2 based on allyl chloride by gas chromatography Example 10 In a 20 1 reaction vessel, which is equipped with a stirrer, a thermometer, an allyl halide inlet tube, the end of which is located in the bottom of the reaction vessel, a cooler with a Tube for the reflux liquid, the end of which is also in the bottom of the reaction vessel and equipped with a 10-stage fractionating column 4,300 g of dimethylformamide with a water content of 0.1%, 2,000 g of sodium cyanate with a purity of 92% and a water content of 0.2%, 75 g of anhydrous Potassium chloride and 7 g of potassium bromide are given. After this Conclude the ailyl halide supply pipe and the line for the reflux solution the contents of the reactor heated to about 900 C with stirring, and 450 mg of formamide were inlet under reduced pressure of 95 to 100 mm and a reflux ratio of 5.0 distilled off. The water content in the system was then 0.03%. then the temperature in the reactor was increased to 1300 ° C. and 2,080 g of allyl chloride were added under its own pressure within 3 hours through the allyl halide feed pipe introduced, this feed pipe and the line for the reflux solution open and the inlet to the fractionating column was closed. Then the allyl halide supply pipe became closed and the reaction solution was kept at 130 to 1350 ° C. for 2 hours with stirring. The reaction solution was then cooled to 600 C and dimethylformamide under distilled under reduced pressure of 25 mm Hg and through the side pipe of the line withdrawn from the system for the reflux solution.

To the residue from crude tri- (allyl isocyanurate) and inorganic Salts were added to 9,500 liters of water and 550 g of 35% strength aqueous hydrogen chloride solution. The mixture was stirred to completely dissolve the inorganic salts, then left to stand and the deposited lower aqueous layer was discarded. To what remained crude tri- (allyl isocyanurate) were given 5,000 1 of water, whereupon the mixture was stirred and then left. The bottom layer of raw Tri- (allyl isocyanurate) was transferred to the distillation device, dehydrated under vacuum under 1000 ° C and then distilled at 1130 C / 0.5 mm Hg. 2,016.5 g of tri- (allyl isocyanurate) were obtained.

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Claims (4)

Process for the preparation of tri- (allyl isocyanurate) P a t e n t a n p r ü c h e Process for the preparation of tri- (allyl isocyanurate) by reaction of an alkali metal cyanate with an allyl halide in an aprotic polar solvent, characterized in that, after the reaction has ended, the solvent removed by distillation from the reaction solution, then water or a aqueous hydrogen chloride solution is added and the formed, the tri- (allyl isocyanurate) containing layer separates from the aqueous layer. 2. The method according to claim 1, characterized in that the Solvent and the alkali metal cyanate in a reaction (3 vessel and then by distillation dehydrated, whereupon the allyl halide is added. 3. The method according to claim 1 and 2, characterized in that one introduces the allyl halide into the liquid phase of the reaction zone. 4. The method according to claim 3, characterized in that the solution obtained by reflux and containing allyl halide into the liquid phase introduces the reaction zone.