DE2050341A1 - Process for the production of malon sauredimtril - Google Patents

Description

FRANKFURt (MAIN), October 13, 1970 Il / r

I 0 Έ ZA A.Ge, Gampel (Canton Valais) Switzerland-,

Management: Basel / Switzerland

Process for the production of malononitrile

The invention relates to a method for producing Malononitrile from acetonitrile at elevated temperature

It is known that malononitrile can be produced by reacting acetonitrile with cyanogen chloride at an elevated temperature. In order to achieve useful yields, based on cyanogen chloride, the reaction was carried out in the presence of chlorine as a catalyst. As was done with a large excess of acetonitrile were sales, based on acetonitrile, at about 0 ^ ^c / i (US Patent 3 4 17 126).

ils is also known to produce pumaric and maleic dinitrile by heating acetonitrile alone to temperatures of 300 to 1200 ⁰ C in the presence of chlorine as a catalyst (Frss.Patentschrift Ί -51 4- 606)

It has now been found that in the absence of halogen, e.g. Chlorine, malononitrile by thermal treatment of Acetonitrile can be produced in high yield.

1098 19/2248

8AD ORIGINAL

The process of the invention is characterized in that acetonitrile in the gaseous "state is heated to temperatures of 600" to 1'TOO ⁰ G for 0.1 Ms 15: seconds, the reaction product is quenched, the unreacted acetonitrile is separated off and returned to the process will.

Reaction temperatures of 700 to 95O ° O and residence times of 1 to 12 seconds are preferably used. If the temperature is increased above 95O ° O, the yields decrease; below 700 ⁰ G there is practically no formation of malononitrile. If the residence time is below or above the stated range, the yields likewise decrease.

It is important to cool the reaction product immediately after the thermal treatment. Expediently, temperatures .of 15 to 30 ° C. Are deterred - ■ · ■ '· - ■ · ^!

The method of the invention thus represents a reijx .thermisches Process in which the.,. Process product is made from a starting material. Alao does not find any implementation of two substances, one of which is a chlorine compound, ■ as in the method of U.S. Patent 3,417,126 of Pail is. Also will be different from this one; and: the one from the French patent known process: worked without chlorine as a catalyst.

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By the method of the invention, there are no chlorine compounds and no chlorine is present and no corrosion is found, ordinary metal tubes or quartz tubes serve as reactors.

The process of the invention can be carried out at normal pressure, reduced pressure or elevated pressure.

ORK31NAL 109819/2248

20503-1

In addition to methane, the by-products of the process are Maleic acid dinitrile and nitrogen compounds.

The unreacted acetonitrile v / ill be separated from Reaktionsgeinisch by distillation and zurüekge- in aen process - leads.

The ^{purification of 1} TUHg of the malonic acid nitrile can be done by fractional distillation.

example

By one to a maximum temperature of 850 ⁰ C heated quartz tube having an inner diameter of 90 mm, wherein a length of 2.4 m, a temperature of 700 ⁰ C and higher was achieved in the gas flow, kg of acetonitrile were reacted within a Sturde 2.027 . The residence time is 11.7 seconds.

The reaction products were quenched and freed from 1.868 kg of unreacted acetonitrile and the latter in the Process returned

The reaction mixture contained 88.5 E malononitrile, which corresponds to a yield based on reacted acetonitrile, of entprieht.

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1098 19/2248 - 4 -

Claims (2)

■ - 4 claims 1) Process for the production of malononitrile from acetonitrile at elevated temperature, characterized in that acetonitrile in the gaseous state is ^{heated to temperatures of 600 to 1100 0} C for 0.1 to 15 seconds, the reaction product is immediately quenched, the unreacted acetonitrile is separated off and stored in the process is returned. 2) The method according to claim 1, characterized in that the acetonitrile is heated to temperatures of 700 to 95O ° Q for ί to 12 seconds and the reaction product is immediately quenched to temperatures of 15 to 3O ⁰ O. 1 09819 / 22A8