DE1126371B - Process for the production of isocyanide dichlorides - Google Patents

Description

Process for the preparation of isocyanide dichlorides Isocyanide dichlorides can generally be prepared by addition of halogen to isonitriles; however, this method is not of practical use because of the instability and unpleasant properties of the isonitriles. In addition, some aromatic isocyanide dichlorides, such as, for example, phenyl isocyanide dichloride, have become accessible by chlorination of the corresponding isothiocyanates. The ardmatischen isocyanide also occur even after the data German Patent 1,094,737 by halogenation of N-Arylformarniden in the presence of thionyl chloride. However, the aliphatic isocyanide dichlorides cannot be prepared in this way.

According to the information in J. pr., 31, p. 120 and 32, p. 298, attempts have already been made to produce phenyl isocyanide dichloride by reacting phenyl isocyanate with phosphorus pentachloride at the boiling point. However, only resinous by-products were obtained here.

It has now been found that aliphatic, aromatic and araliphatic isocyanide dichlorides are obtained if isocyanates or isothiocyanates are reacted with phosphorus pentachloride at room temperature or at a slightly elevated temperature, preferably from 20 to 100 ° C.

The following formula scheme should clarify this implementation: R - N # C = X + PCI5 ---> R - N = CCI2 + PXCI3 In the above formulas, R stands for any optionally substituted aliphatic, aromatic or araliphatic radical, X stands for sulfur or oxygen.

Any mono- or polyisocyanates or isothiocyanates of the aliphatic, aromatic or araliphatic Rc #, he used will.

The reaction can be carried out with the pure substances without solvents, by increasing the isocyanate or isothioeyanate at room temperature or slightly higher Temperature on phosphorus pentachloride or a solution of chlorine and phosphorus trichloride can act. For the reaction to proceed better, however, it is more advantageous to in a solvent, expediently in that formed in the reaction To work phosphorus oxychloride or phosphorus sulfochloride.

Finally, the reaction can also be carried out in an organic solvent that can no longer be chlorinated, such as carbon tetrachloride, dichlorobenzene or the like .

The process products are valuable intermediate products for manufacture of pesticides and medicinal products.

Example 1 18 g of methyl cyanate are added dropwise to a suspension of 70 g of phosphorus pentachloride in 70 ml of phosphorus oxychloride. The reaction mixture is stirred for some time at room temperature and the almost clear solution is distilled over a column filled with Raschig rings. This gives 38 g of a distillate with a boiling point of 60 to 85 ° C. During redistillation, 29.5 g = 83.50 / 0 of theory of methyl isocyanide dichloride with a boiling point of 79 to 80 ° C.

Example 2 25 g of methyl isothiocyanate are slowly added dropwise at room temperature into a suspension of 70 g phosphorus pentachloride in 50m1 o-dichlorobenzene. A slight warming occurs here. The mixture is heated to 100'C for 1/2 hour and then distilled at a bath temperature of 180'C. This gives 54 g of a boiling mixture with a boiling point of 70 to 110 ° C. During redistillation, 24 g of methyl isocyanide dichloride with a boiling point of 77 to 790 ° C. pass over. Yield: 620/0 of theory.

Example 3 36 g of ethyl isocyanate are added dropwise to 104 g of phosphorus pentachloride at room temperature. The temperature rises to about 37 ° C. The mixture is heated at 900 ° C. for 1/2 hour without complete dissolution occurring. After removing the excess phosphorus pentachloride, the solution is distilled over a column filled with Raschig rings. After a short preliminary run, which contains some ethyl carbamic acid chloride, 54 g = 860/0 of the theory of ethyl isoeyanide dichloride with a boiling point of 100 to 101 ° C. are obtained.

Example 4 49 g of n-butyl isocyanate are added dropwise at 55 ° C. to a suspension of 104 g of phosphorus pentachloride in 80 ml of phosphorus oxychloride. Gradual solution occurs here. The phosphorus oxychloride is distilled off and n-butyl isocyanide dichloride is obtained as residue, which passes over during vacuum distillation at bp-14 45 to 45.5 ° C. Yield: 38 g = 50010 of theory.

Example 5 125 g of cyclohexyl isoyanate are added dropwise at 40 ° C. to a suspension of 208 g of phosphorus pentachloride in 150 ml of phosphorus oxychloride. The mixture is stirred for about 5 hours at this temperature until it is completely dissolved. After evaporation of the phosphorus oxychloride, 83 g of cyclohexyl isocyanide dichloride with a boiling point of 12 82 to 83.5 ° C. are obtained by fractionation. Example 6 77 g of p-C-phenyl isoeyanate are dissolved in 150 ml of phosphorus oxychloride and then 105 g of phosphorus pentachloride are added. The mixture is stirred for a few hours at room temperature, then slowly heated to 80 ° C., during which time solution occurs within about 15 minutes. After the solvent has been distilled off, 38 g of p-chlorophenylisoeyanide dichloride with a boiling point of 14 117 to 1200 C. are obtained by distillation.

EXAMPLE 7 38 g of 1,3-phenylene diisocyanate are added at 40 to 50 ° C. to the suspension of 104 g of phosphorus pentachloride in 80 ml of phosphorus oxychloride. The mixture is stirred for a few hours, then heated to 90 ° C. for 1/2 hour and the solvent is distilled off. Distillation gives 13 g of 1,3-phenylene diisocyanide dichloride with a boiling point of 1.5 160 to 161 ° C.

Example 8 A mixture of 42g of dodecyl isocyanate, 40 g of phosphorus pentachloride and 60 ml of phosphorus oxychloride is stirred for 6 hours. Almost complete solution has occurred after standing overnight. The excess phosphorus pentachloride is separated off and, after evaporation of the solvent, it is distilled in vacuo. Bp 15 163 to 166 'C. Yield: 14 g.

Claims (1)

PATENT CLAIM: Process for the preparation of isocyanide dichlorides, characterized in that mono- and polyisocyanates or isothiocyanates are reacted with phosphorus pentachloride, optionally in the presence of solvents, at room or slightly elevated temperatures, preferably from 20 to 100 ° C. References considered: J. Am. Chem. Soc., 44, p. 2897, reports d. German chem. Ges., 6, p. 322 (1874), 1. Prakt. Ch., 31, p. 120; 32, p. 298.