DE3324905A1 - Process for the preparation of N,N'-bis-trifluoromethyltetra- fluoroethylenediamine - Google Patents

Abstract

The present invention relates to a process for the preparation of N,N'-trifluoromethyltetrafluoroethylenediamine, characterised in that tetrachloroethylene 1,2-bis-isocyanide dichloride is reacted with anhydrous hydrofluoric acid in a diluent at a pressure of 5 to 30 bar, characterised in that the process is carried out under high thermal stress at temperatures from 80-150 DEG C, and, after the reaction, the reaction mixture formed is distilled at a reflux ratio of 2:1 to 10:1 and a pressure of 1-5 bar under high thermal stress.

Description

Process for the preparation of N, N'-bis-trifluoromethyl-

tetrafluoroethylene diamine The present invention relates to a new one Process for the preparation of N, N '-Bis-trifluoromethyl-tetrafluoroethylene diamine.

It is known that N, N'-bis-trifluoromethyl-tetrafluoroethylene diamine obtained by tetrachlorethylene-1,2-bisisocyanide dichloride with anhydrous hydrofluoric acid until the chlorine atoms have been completely exchanged for fluorine atoms (DE-OS 2 012 435). In order to arrive at a pure product, it is necessary to have pure starting material to use.

It has now been found that N, N'-bis-trifluoromethyltetrafluoroethylene diamine obtained when tetrachlorethylene-1,2-bisisocyanide dichloride is used with anhydrous hydrofluoric acid reacted in a diluent at a pressure of 5 to 30 bar, characterized in that that one under high thermal stress at temperatures from 80 - 1500C works and the resulting reaction mixture after the reaction under high thermal load with a reflux ratio of 2: 1 to 10: 1 and distilled at a pressure of 1-5 bar.

It was surprising that with this way of working you can also work with a Isocyanide dichloride with a content below 90% to an equally pure tetrafluoroethylene diamine gets like a pure isocyanide dichloride. This was therefore particularly surprising because it was known that tetrafluoroethylene diamine is not very thermally stable.

One would therefore have had to expect that it would be under the work-up high thermal stress at least partially disintegrates, or undesirable by-products forms.

The process is carried out under high thermal stress in such a way that that one submits the isocyanide dichloride in a suitable diluent, the the resulting suspension is heated to 80 to 1500C at a pressure of 5 to 30 bar, then the anhydrous hydrofluoric acid is metered in under pressure. One then leaves under high react to thermal stress for approx. 1 to 10 hours at 100 to 1500C and 5 to 30 bar, cools down to 10 to 500C and relaxes to 1 to 3 bar.

Thereafter, the reaction mixture is distilled under high thermal Worked up burden. With a reflux ratio of 2: 1 to 10: 1, preferably 3: 1 to 8: 1, distilled under a pressure of 1-5 bar, preferably 1-3 bar.

The term high thermal load results from the Arrhenius law, according to which the connection between a reaction speed r and the reaction temperature T are generally described by the following equation can be 2): -EA A r = O. X RT c = Conc. d. Reactants n = reaction order EA = Activation energy R = general gas constant T = temperature r = dc / dt t = time ko = impact factor caused by the generally negative activation energy EA an increase in temperature an increase in the reaction rate, which results in first approximation (RGT rule from van t'Hoff, p.1)) doubles when the temperature is increased by 100C.

1) see John Eggert, Textbook of Physical Chemistry, Stuttgart, 1960, p. 746 f.

2) Klaus Ruft, recording the reaction time in batch processes, Chem.-Inf.-Techn. 55 (1983) No. 4, pp. 305-306.

Chemical reactions can be caused by high thermal loads, that is high temperatures or long reaction times or a combination out of both, lead far towards their end products.

Because in chemical engineering there are long reaction times - but also high Temperatures - are not desired, the optimum will be determined for each individual case have to.

All of the interrelationships have the effect that a process that is the same Reaction time is carried out once at 800C and another time at 110 ° C the higher temperature is subject to approx. 6 times the thermal load the variant with a lower temperature.

Therefore, under technical conditions, the method is used with the Correct higher temperature in order to achieve large space-time yields.

For example, the fluorination process can be carried out at 110 "C within 14 Hours of effective reaction time can be carried out or at 1000C with approx. 28 hours Reaction time.

The higher pressure required at the higher temperature (18 bar at 1100C), however, sets an upper limit.

The process is preferably carried out in a nickel or nickel autoclave VA steel, a metering device and a distillation device for distillation contains under pressure.

Hydrogen fluoride is preferably used in an excess of 0.5 to 10 mol. The excess hydrogen fluoride is recovered in the distillation and can be used again in the reaction.

Suitable diluents are preferably optionally halogenated Hydrocarbons such as methylene chloride, ethylene chloride, aromatics such as toluene, xylene, Chlorobenzene. Particular mention should be made of chlorobenzene.

The reaction is preferred at temperatures above 1000C carried out between 100 and 1500C, particularly preferably at 110 to 1300C.

The reaction is particularly carried out at 5 to 30 bar, preferably 10 to 25 bar preferably carried out at 12 to 20 bar pressure.

The metering in of the hydrogen fluoride to the suspension of the isocyanide dichloride in a diluent takes place at about 110 to 130 ° C and 15 to 20 bar pressure. The hydrogen fluoride is added over a period of 5 to 15, preferably 8 to 10 hours metered in.

The post-reaction takes place preferably at 100 to 150 ° C., particularly preferably at 110 to 1300C and 10 to 25 bar or 12 to 20 bar pressure over a period of time from 1 to 5 hours, preferably over 1 to 2 hours.

The hydrogen fluoride is at 1-5 bar, preferably at approx.

2 bar pressure and a reflux ratio of 3: 1 to 8: 1 distilled off.

The N, N'-bis-trifluoromethyl-tetrafluoroethylene diamine is a known one Link.

It is a valuable intermediate for making highly effective products Acaricides and fungicides.

Example 1 In an autoclave made of stainless steel, with stirrer, Thermometer and a reflux condenser with a downstream exhaust gas control valve 580 kg of tetrachlorethylene-1,2-bisisocyanide dichloride (86% content) in 240 kg of chlorobenzene suspended and heated to 1100C.

12 bar N2 protective pressure is applied and then within 625 kg of hydrogen fluoride are metered in for 8 to 10 hours. The pressure is increased to 18 bar. The reaction is allowed to continue for 2 hours at 110.degree. C., then cooled to 30.degree. C. and the pressure is released the hydrogen chloride released during the reaction via the exhaust valve except for 2 bar.

The excess hydrogen fluoride is then distilled off at 2 bar. About 300 kg of reaction mixture are obtained.

The reaction mixture is then distilled. N, N'-bis-trifluoromethyl-tetrafluoroethylene diamine is obtained in a yield of 80%.

The following experiments are carried out analogously to Example 1: Reaction content of the distillation Clw> hold yield temperature pressure output m. Return flow of the final end product product 70-90 OC 7 - 12 bar 90% 3: 1 2.5% 83 % 1150C 19 bar 90% 8: 1 0.5% 81%

Claims (1)

Claims 1. A process for the preparation of N, N'-bis-trifluoromethyl-tetrafluoroethylene diamine, by adding tetrachlorethylene-1,2-bisisocyanide dichloride of the formula C12C = N-CC12-CC12-N = CC12 with anhydrous hydrofluoric acid in a diluent at a pressure of 5 to 30 bar converts, characterized in that at high thermal load at Temperatures of 80-1500C are used and the resulting reaction mixture follows to the reaction under high thermal stress at a reflux ratio of 2: 1 distilled at 10: 1 and a pressure of 1 - 5 bar.