DE977532C - Process for the production of alkyl tin compounds besides alkyl tin halogen compounds - Google Patents

Description

Process for the production of alkyl tin compounds besides alkyl tin halogen compounds the The invention relates to a simple and economical method of production of alkyl tin compounds in addition to alkyl tin halogen compounds. These products are known per se; they serve as intermediates for organic syntheses and become used, among other things, as stabilizers for synthetic resins.

Various methods of making organotin compounds have been used suggested. In particular, it is also known to use an alkyl halide with magnesium To implement Grignard compound and from the latter and a tin tetrahalide in a second stage to produce alkyl tin compounds.

It is also known that one can produce the Grignard compound Usually ether used as a solvent after Grignardation has been completed by other higher-boiling solvents and in particular inert hydrocarbons replace and carry out the subsequent reaction in the newly introduced reaction medium can.

Attempts have also been made to make Grignard compounds directly without Using ether in hydrocarbons such as benzene as a solvent to produce however, the results were very unsatisfactory, the Grignardizations proceeded slow and the yields of organomagnesium halide were low, so that one Applying this procedure on a larger scale was not considered. In one case, one has the Grignardation carried out in benzene a Ester or a ketone added from the start; this has been done for some components a relatively smooth course that is coupled with the subsequent implementation in this case Grignarding, but with a partially unexpected result. However could this working method, which according to the information of the author on alkyl bromides and iodides, when using ketones or esters, not with the the usual two-step working method, in which the Grignardation and Subsequent conversion must be carried out separately because of the considerable amount of by-products incurred, which not only impaired the yield of the desired compound, but often also made their isolation difficult or almost completely prevented.

There has now been a one-step process for making alkyl tin compounds found in addition to alkyltin halogen compounds, in which the products mentioned in high Yield and purity can be obtained. For this purpose one brings in in itself more usual Way activated magnesium in one of an aromatic or a saturated aliphatic hydrocarbon and optionally a catalytic amount of ether be standing solvent with only a part of the alkylmagnesium halide formation required alkyl halide together gives the residual amount of alkyl halide after the reaction has started together with the tin tetrahalide at such a rate that the reaction of the components to the alkyl tin and alkyl tin halogen compounds at 65 to 1800 C, preferably 85 to 950C, expires quickly, and isolates the resulting tin alkyl and tin alkyl halogen compounds from the reaction mixture and purify them in on usual way.

According to the invention, alkyl halides can in particular also be used Use alkyl chlorides in the above-mentioned known one-step Grignardation process remained unresponsive. Another advantage is that no or practical no ether is used, the use of which is known to be used in Grignardizations in larger scale is associated with considerable dangers.

Furthermore, one obtains in the known preparation of alkyl tin compounds a viscous reaction mixture of tin tetrachloride and alkyl Grignard reagents in ether and only low yields. When working with the proposed according to the invention inert solvents in the absence of ether or in the presence only catalytically Acting amounts of ether, on the other hand, form reaction mixtures that are not viscous are easy to process, can be heated to higher temperatures and deliver high yields.

When carrying out the process according to the invention, the implementation with part of the alkyl halide and the magnesium in the presence of an inert one aromatic or saturated aliphatic hydrocarbon in the usual way initiated. Once the reaction has started, the rest of the alkyl halide will be and the tin tetrahalide is added simultaneously at such a rate that the implementation continues quickly. The reaction temperature is between 65 and about 1800 C, preferably between 85 and 950 C. The higher temperature is preferred because it ensures a higher degree of implementation.

The magnesium is in the amount required for reaction with the alkyl halide Amount applied. The ratio of alkyl halide to tin tetrahalide is directed depending on the type of end product desired. However, it has been found that in in all cases optimum yields of organotin compounds using a high one Ratio of alkyl halide to tin tetrahalide are obtained, being predominantly Tin tetraalkyls are formed alongside trialkyltin halides.

Example I 24.0 g (I mol) of magnesium turnings were put into a stirrer, 1 liter three-neck flask fitted with a reflux condenser, thermometer and dropping funnel given. The magnesium was with an iodine crystal, 1 ccm ethyl bromide and 10 ccm absolute ethyl ether added. As soon as the reaction had started, something about the exotherm could be seen, 100 ccm of toluene were added and the batch to 80 to 850.degree warmed up. Then a mixture of 92.5 g (1 mol) of butyl chloride and 65.2 g (0.25 Mol) tin tetrachloride in 200 ccm toluene was added dropwise with stirring. the Implementation began immediately, as indicated by sludge formation and increased boiling became.

It was not heated any further at first because the heat of reaction increased Maintaining the temperature was sufficient. The mixture was made asap added without overloading the cooler. When the addition was complete, 1/2 to was added Heated under the reflux condenser with stirring for 1 hour. Then the batch was cooled and filtered or extracted with acidified water and the toluene solution Solvent distilled off.

The organotin compounds were fractionated in vacuo. It was a yield of about 85 ° lo, calculated on butyl chloride, and goole, calculated on tin tetrachloride. The product consisted mainly of (C4H9) 4Sn and (C4Hg3sSnCl in addition to a small amount of (C4H9) 2SnCl2.

Example 2 24 g (I mol) of magnesium shavings were poured into a 1 liter three-neck flask fitted with a reflux condenser, thermometer and dropping funnel given. 2.5 g of butyl chloride in 80 cc of toluene was added and the mixture was heated until the beginning of the reaction can be recognized. Then a mixture of go g of butyl chloride and 65.2 g of tin tetrachloride in 200 cc of toluene drop by drop added with stirring. Once the reaction became exothermic, heating was stopped stopped until the reaction wore off. After adding the reactants was complete, the reaction mixture was stirred for a further 1 hour on the reflux condenser heated.

Then the reaction mass slowly increased in volume Entered water that contained IO / o hydrochloric acid or sulfuric acid. After everything unreacted magnesium decomposed and all of the magnesium chloride was dissolved, the toluene layer was removed and the solvent was distilled off. The received Products were practically the same as in Example I.

The process which is the subject of the invention is particular suitable for the large-scale production of alkyl zinc compounds. Here can be worked with conversion mixtures of 4000 liters, initially small Amounts of the alkyl chloride and tin tetrachloride with magnesium and a solvent of the type mentioned are introduced into the reaction vessel.

The reaction is then carried out with a catalytic amount of ethyl bromide and ethyl ether set in motion, and the remaining amount of the batch of 4000 Liters are added over the course of approximately 2 hours. When the addition is complete, the Implementation practically complete, although the mixture was stirred for a further 30 minutes as usual can be.

The achievable yields, based on tin tetrachloride, are between 95 and 98 ° / o.

Claims (2)

PATENT CLAIMS: I. Process for the preparation of alkyl tin compounds in addition to alkyltin halogen compounds, characterized in that in per se more usual Way activated magnesium in one of an aromatic or a saturated one aliphatic hydrocarbon and optionally a catalytic amount of ether existing solvents with only a part of the for alkylmagnesium halide formation brings together required alkyl halide, after the reaction has started Residual amount of alkyl halide along with tin tetrahalide at such rate admits that the reaction of the components to the alkyl tin and alkyl tin halogen compound at 65 to 1800 C, preferably 85 to 950 C, expires quickly and you the resulting Tin alkyl and tin alkyl halogen compounds isolated from the reaction mixture and cleans in a conventional manner. 2. The method according to claim I, characterized in that as Alkyl halide is an alkyl chloride and tin tetrachloride is used as tin tetrahalide.