DE2152971B2 - Process for the preparation of organic sulfonyl isocyanates - Google Patents

Description

The production of organic sulfonyl isocyanates by phosgenation of corresponding sulfonic acid amides is known. According to GB-PS 692360, this reaction takes place at temperatures of 160 to 250.degree carried out.

The reaction of organic sulfonic acid amides with phosgene can accordingly be more gentle US Pat. No. 3,371,114 in the presence of a hydrocarbyl isocyanate Carry out at temperatures between 60 and 200 ° C. Finally, US Pat. No. 3,379,758 describes the phosgenation of N-arylsulfonyl-N'-alkyl ureas to arylsulfonyl isocyanates at temperatures between 0 and 175 ° C. All processes there is a lack of sulfonyl chlorides to a considerable extent under the claimed process conditions arise as undesirable by-products. Organic sulfonyl isocyanates and sulfonyl chlorides show only slight in terms of molecular weight and consequently physical properties Differences and can only be determined under considerable, i. H. costly effort, from each other separate.

If you want sulfonyl isocyanates of a high degree of purity win, one is forced to initiate the formation by appropriate chemical reaction to keep sulfonyl chloride as small as possible in order to save time-consuming cleaning operations.

As has now been found, surprisingly, sulfonyl isocyanates can be prepared to a high degree Degree of purity if catalytic amounts are used in the reaction between sulfonic acid amide and phosgene used on primary amines.

The present invention thus relates to a process for the preparation of organic sulfonyl isocyanates high degree of purity according to the preceding claim.

In the process according to the invention, any primary aliphatic, cycloaliphatic, araliphatic ^, aromatic and / or heterocyclic mono- and / or polyamines are used. Preferably become aliphatic, cycloaliphatic and araliphatic in the process according to the invention primary mono- and / or polyamines used, especially higher-boiling representatives of this class of substances with 6 to 18 carbon atoms in the molecule. Examples v <5ii suitable for the method of discovery Amines are methyl, ethyl, propyl, isopropyl, n-, sck-, tort.-, butyl, hexyl, octyl, dodecyl, octa-

decyl, cyclopentyl, cyclohexylamine, benzylamine, Aniline p-nitroaniline, p-ethoxyaniline or m-bromoaniline. It is also advantageous to use polyamines such as 1,6-diaminohexane, 2,4-diaminotoluene, 1,5-naphthalenediamine or 4,4'-diamino-diphenylmethane.

Aliphatic, use cycloaliphatic and aromatic, optionally substituted mono- and polysulfonic acid amides, for example methanesulfonamide, ethanesulfonamide, butanesulfonamide, dodecanesulfonamide, hexadecanesulfonamide, Oxtadecanesulfonamide, benzenesulfonamide, the isomeric toluenesulfonamides, the isomeric xylene sulfonamides, the isomeric naphthalene sulfonamides, the isomeric naphthalene disulfonamides and the isomeric anthracene sulfonamidebzw. -disulfonamides. The corresponding chlorine- or bromine-substituted aromatic sulfonamides can can also be used in the process according to the invention. There are in the invention Process alkanesulfonamides with 1 to 18 carbon atoms or aromatic sulfonamides with 6 up to 14 carbon atoms are used.

As inert solvents are recommended, for. B. aliphatic and / or aromatic, optionally substituted Hydrocarbons, ethers or nitriles such as hexane, white spirit, benzene, toluene, xylene, chlorobenzene, Dichlorobenzene, trichlorobenzene, chlophen, carbon tetrachloride, nitrobenzene, dioxane, benzyl cyanide or benzonitrile.

In the production of organic sulfonyl isocyanates, the sulfonic acid amide is preferably used first, optionally with heating, in an inert to phosgene and sulfonyl isocyanates Solvent dissolved, the Arniii to be regarded as a catalyst added in such amounts that per VaI sulfonamide groups are less than 0.1, preferably 0.001 to 0.099 VaI amine and at temperatures between 50 and 150 ° C., preferably 80 and 135 ° C., phosgene introduced until the sulfonic acid amide is completely converted to sulfonyl isocyanate. Excess phosgene is then used and displaced hydrogen chloride gas by introducing nitrogen, for example, the solvent distilled off and the remaining sulfonyl isocyanate generally with no fractionation subjected to distillation.

The accessible by the method according to the invention Organic sulfonyl isocyanates are valuable intermediates, for example for the production of antidiabetic drugs are used. In the field of polyurethane plastics, they serve as Aid for drying solvents, paints and pigments. The following explain more Examples.

example 1

171 g (1 mole) of p-toluenesulfonic acid amide and 0.57 g (0.049 mol) of hexane-1,6-diamine are dissolved in 686 g of chlorobenzene with heating. The sulfonamide concentration of the solution is 20% by weight. Phosgene is passed in at 125 ° C. while stirring until the sulfonyl isocyanate content no longer increases. Excess phosgene is then added displaced by passing in nitrogen, the solvent is separated off by distillation and the crude sulfonyl isocyanate by distillation under reduced

Print - without fractionating - cleaned.

A mixture of 183.5 g of p-toluenesulfonyl isocyanate is obtained (97.7% by weight) and 4.4 g of p-toluenesulfonyl chloride (2.3 wt%).

Comparative example 1
(in analogy to US-PS 3379758)

In a 20% chlorobenzene solution of a bis-sulfonylurea, as can be obtained by reaction of 2 moles of p-toluenesulfonic acid amide and 1 mole Hexane-1,6-diisocyanate is obtained, phosgene is passed in at 100 ° C. for 5 hours and then the Reaction product worked up according to Example 1.

176.3 g of a mixture of 154 g of p-toluenesulfonyl isocyanate are obtained (85.5% by weight) and 22.3 g of p-toluenesulfonyl chloride (14.5% by weight). The yield at p-Toluenesulfonyl isocyanate is only 78% of theory.

Example 2

To a 15% solution of p-toluenesulfonamide in chlorobenzene - produced from 60 kg (350 mol) of p-toluenesulfonic acid amide and 170 kg of chlorobenzene 0.25 kg (3.42 mol) of n-butylamine were added and then phosgene for 12 hours at 130 ° C (3 kg / h) initiated. After working up the crude sulfonyl isocyanate solution - As described in Example 1 - a mixture of 31.6 kg of p-toluenesulfonyl isocyanate is obtained (98.14% by weight) and 0.595 kg of p-toluenesulfonyl chloride (1.86% by weight). The yield of p-toluenesulfonyl isocyanate is 91.5% of theory.

Comparative example 2
(in analogy to US-PS 3379758)

When implementing a 15% chlorobenzene Solution of 270 g (1 mol) of N- (p-toluenesulfonyl) -N '- (n-butyl) urea with phosgene At 100 ° C., 101 g of p-toluenesulfonyl isocyanate (89.2% by weight) are mixed with 12.3 g of p-toluenesulfonyl chloride (10.8% by weight).

The yield of p-toluenesulfonyl isocyanate is only 51% of theory.

Examples 3 to 7

In a manner similar to that described in Example 1, 1 mol of p-toluenesulfonamide in each case is in a 20% solution in Chlorobenzene at 125 ° C in the presence of 0.01 mol of each of the tabular monoamines as Phosgenated catalysts, the following results being obtained:

at Amine yield salary game p-toluene p-toluene sulfonyliso sulfonyl cyanate in% chloride in the theory Wt% 3 n-propylamine 95.0 0.46 4th Dodecylamine 92.5 0.89 5 Benzylamine 82.0 0.82 6th aniline 24.0 1.58 7th p-ethoxyaniline 37.0 1.65

, ο example 8

One passes into a 20% solution of 1 mol of p-toluenesulfonamide in xylene at 130 ° C in the presence of 0.005 mol of diamino-diphenylmethane for 20 hours of phosgene, so you get after the up- - ') Working 62% of the theory p-toluenesulfonyl isocyanate with a p-toluenesulfonyl chloride content of 1.44% by weight.

Example 9

! » Similar to that described in Example 1, the result Phosgenation of p-chlorobenzenesulfonamide in the presence of 0.049 moles of hexane-1,6-diamine per mole of sulfonamide with the corresponding sulfonyl isocyanate a yield of 76% of theory. The content of

i'i p-chlorobenzenesulphonic chloride is 1.33%.

Example 10

171 g of ortho-toluene-sulfonic acid amide are in Dissolved 700 g of dichlorobenzene and, after adding 0.5 g of 4 »hexane-1,6-diamine, treated with phosgene at 121 ° C. 176.5 g of ortho-toluenesulphonyl isocyanate are obtained (89.5% of theory), which is only marginally caused by suI-fochlorid is contaminated.

Claims (1)

Claim: Process for the production of organic sulfonyl isocyanates of high purity by Implementation of solutions of alkanesulfonamides, the 1 to 18 carbon atoms or of aromatic Sulfonamides which have 6 to 14 carbon atoms, with phosgene in inert ones Solvents, characterized in that the reaction is carried out in the presence of mono- and / or polyamines, in an amount of less than 0.1 VaI amino groups, per VaI sulfonamide groups, in the reaction mixture.