DD276854B1 - PROCESS FOR PREPARING TIN (II) CHLORIDES - Google Patents

Description

Field of application of the invention

The invention relates to a process for the preparation of Zlnn (II) chlorides by reacting vo.i metallic tin with tin tetrachloride.

Such products are used as mordants in dyeing or bleaching agents in the textile industry, but primarily as raw materials for the production of tin (II) salt, in particular tin (II) carboxylates.

Characteristic of the known state of the art

The preparation of tin (II) chlorides from metallic tin and tin tetrachloride has been described many times in the literature and has been practiced for some time.

The reaction between the two reactants can either take place in such a way that vaporous tin tetrachloride acts on molten metallic tin, or the reaction takes place in the presence of water.

The last-mentioned process principle represents the more elegant solution, since it is not only easier to carry out, but also produces purer tin (II) chlorides in higher yield.

The object of the "JS-PS 3816602" is that by molar ratios of metallic tin and tin tetrachloride, advantageously 4 mol of water are required for 1 mol of tin Due to the relatively low amount of water, the product obtained inevitably arises as salt mash or salt Melting, which is why logically drainage at higher temperatures must follow.

Although the space-time yield is higher than in the processes with absence of water, overall it is - as well as the purity of the final products - worthy of improvement.

This is equally true for the tin (II) content, the amount of which is of decisive importance especially in the further processing of tin (II) carboxylates to be catalyzed.

Object of the invention

The aim of the invention is therefore to eliminate the defects resulting in the production of stannous chlorides from the prior art in terms of space-time yield and purity and tin (II) content or to turn off as far as possible.

Explanation of the essence of the invention

It is therefore the object to develop by suitable additives and thus changed reaction conditions, a process for the preparation of stannous chloride, which corresponds to the above objectives.

According to the invention ZinndD chlorides with improved space-time yield in high purity and with increased tin (II) content obtained when the reaction of metallic tin with tin tetrachloride in the presence of a tin-containing system and optionally sorbitol or pentaerythritol at a water content of at least 100 %, based on the tin components used, takes place.

Essential to the invention here is that the tin-containing system has resulted from the reaction of metallic tin with tin tetrachloride, using hydrochloric acid.

Also essential to the invention is the proportion of the tin-containing system in the reaction mixture. In this context, a proportion of 15-20%, preferably 16-17%, in each case based on the metallic tin used, has proved to be advantageous.

embodiments

1. 120g of tin granules and 270g of water are placed in a reaction vessel. Subsequently, 20 g of a tin-containing system, which was obtained from 17 g of tin metal, 2 g of tin tetrachloride and 1 g of concentrated hydrochloric acid, to. While stirring, 263.5 g of tin tetrachloride are added dropwise, wherein an exothermic reaction takes place and the temperature rises to 85 ⁰ C. After 20 minutes, the reaction is completed.

The tin (II) chloride solution thus obtained is decanted after a clarification process and contains 36.7% Sn with 99.8% tin (II) content, resulting in a yield of 99.6%, based on the tin tetrachloride used.

Disturbing impurities from the tin metal used, such as antimony, arsenic, copper and lead, could not be detected in the clarified tin (II) chloride solution.

After storage for 3 months no Abschoidungen were observed from the solution.

2. The procedure is analogous to Example 1 and are added to 120g tin metal and 300g water 18g of a tin-containing system and 2g sorbitol. After the addition of 263.5 g of tin tetrachloride, the reaction is complete after 8 minutes at 82 ° C.

The resulting tin (II) chloride solution is decanted after the clarification process and contains 35.1% Sn at 100% ZinndD proportion.

Based on the tin tetrachloride used, this means a yield of 100%.

The purity corresponds to that according to Example 1; after 3 months of storage, slight turbidity, but no deposits show.

3. The procedure of Example 1-2 and gives 120g of tin metal and 330g of water 24g of a tin-containing system and 3g pentaerythritol. Mach 12 minutes the reaction with tin tetrachloride 263,5g at 8O ⁰ C is completed.

The obtained Zinr (II) chloride solution is decanted after the clarification process and contains 33.6% Sn at 100% ZinndD proportion. Purity and storage stability were determined analogously to Example 2.

Document contemplated: US-PS 3816602, C 01 G 19/08

Claims (2)

1. A process for the preparation of stannous chlorides by reacting metallic tin with tin tetrachloride in the presence of water, characterized in that the reaction in the presence of a tin-containing system, resulting from the reaction of metallic tin with tin tetrachloride in the presence of hydrochloric acid, and optionally sorbitol or pentaerythritol at a water content of at least 100%, based on the tin contained in the tin components used. 2. The method according to claim 1, characterized in that the proportion of the tin-containing system is 15-20%, preferably 16-17%, each based on the metallic tin used.