DE1064050B - Process for drying heavy metal salts of ethylene bisdithiocarbamic acid - Google Patents

Description

C O 7 C 4-

FEDERAL REPUBLIC OF GERMANY

GERMAN

kl. 12 ο 17/02

INTERNAT. KL. C 07 C

PATENT OFFICE

EXIT FAILURE 1064 050

Sch 22487 IVb / 12 ο

REGISTRATION DAY. JULY 18, 1957

NOTICE /

THE REGISTRATION

AND ISSUE OF THE

EXPLORATION PAPER: AUG U ST 27, 19 5 9

The French patent specification 1 099 969 discloses a process for the preparation of dithiocarbamic acid derivatives of ethylene diamine or of heavy metal salts of ethylene bisdithiocarbamic acid known, in the case of carbon disulfide with ethylenediamine in an aqueous medium in the presence of a weak one Base, in particular ammonia, is implemented. In the French patent, however, there are only yields for crude products of 83.5 and 85%.

Tests have shown that these unsatisfactory yields in no way correspond to the manufacturing process specified there are peculiar, but only through inexpedient drying of the in itself almost quantitative yield of the crude product that is still moist with suction filter: with a aliquot part of the suction-moist zinc ethylene bisdithiocarbamate prepared according to French patent specification 1 099 969 corresponded to the content of ethylene bisdithiocarbamic acid (determined by decomposition with acid and determination of the carbon disulfide formed as xanthate after Clarke, Analyt. Chem., 23, pp. 1842 to 1846) about 95 to 97% of theory. Contained the same zinc salt however, after drying an approximately 3 cm thick layer in a circulating drying cabinet for 24 or 17 hours at 50 or 80 ° C only 83 or 86% pure active ingredient. There were similar losses in titre during drying of the manganese salt of ethylenedisdithiocarbamic acid prepared in an analogous manner. Drying at 100 ° C after 5, 30 or 120 minutes resulted in a loss of titer of 4.5, 6.5 or 18.5%.

It has now been found that even after the production process of the French patent excellent yields and high degrees of purity of the dry end products can be achieved, if one considers the drying of the moist heavy metal salts obtained in a thin layer at temperatures from 90 to 140 ° C, preferably 100 to 120 ° C, within a relatively short period of time, preferably a few seconds.

For technical reasons it is advantageous to carry out the drying with the aid of drum dryers.

It has been shown that to achieve the desired effect drying temperatures of about 90 to 140 ° C can be used, those from 100 to 120 ° C are particularly advantageous for reasons of apparatus, whereby the drying times are limited to a few seconds.

That such a thermally unstable salt as the heavy metal salts of ethylene bisdithiocarbamic acid is so high Tolerating drying temperatures is surprising.

Method of drying

of heavy metal salts

of ethylene bisdithiocarbamic acid

Applicant:

Schering Aktiengesellschaft, Berlin N 65, Müllerstr. 170-172

Carl-Otto Laubschat, Berlin, has been named as the inventor

It was also unforeseeable that a short drying time at high temperatures compared drying at lower temperatures and correspondingly longer drying times are the ones found would offer significant advantage.

example

Nutschefeucht produced by the process according to French patent specification 1,099,969 Zinkäthylenbisdithiocarbamat is applied within 8 hours in a 0.5 mm thick layer on a drum dryer dried at 115 ° C. The dried product contains 97% pure active ingredient.

Other heavy metal salts of ethylene bisdithiocarbamic acid, e.g. B. the manganese salt, are in analog Way dried with equally good success, the drying temperatures to be used if necessary are to be varied appropriately within the range specified in the description.

Claims (2)

Patent claims: 1. Process for drying heavy metal salts of Äthylenbisdithiocarbamic acid, which are described in known way by reacting carbon disulfide with ethylenediamine in the presence of Ammonia and subsequent treatment of the reaction solution with soluble heavy metal salts have been prepared, characterized in that the drying of the salts in thinner Layer at temperatures of 90 to 140 ° C, preferably 100 to 120 ° C, within a relative a short period of time of preferably a few seconds. 2. The method according to claim 1, characterized in that the drying by means of a Drum dryer performs. © 909 609/427 8. 59