DE1131197B - Process for the production of fluorine- or chloroalkanes, which have up to two carbon atoms - Google Patents

Description

There are already a number of possibilities for the preparation of aliphatic chlorinated hydrocarbons has been described by the reaction of organic sulfonic acid derivatives. It is already like that known from German Patent 362 741, ethyl chlorosulfonate with hydrochloric acid to form ethyl chloride to implement. In US Pat. No. 2,688,641, the reaction of diethyl sulfate with Sodium chloride described for ethylene chloride under certain conditions. The thermal Decomposition of sulfonic acid chlorides of higher molecular weight aliphatic hydrocarbons, whereby the corresponding chloroalkanes are to be formed, is proposed in German Patent 740,677.

In the known thermal decomposition of halosulfonic acid esters, such as, for example is described by Behrend in the Journal for Practical Chemistry, Vol. 15, 1877, pp. 33 and 34, black, tarry, undistillable products are obtained, their formation on the oxidizing effect of the sulfur trioxide that occurs during the decomposition.

It has now been found, surprisingly, that the thermal decomposition of fluorine resp. Chlorosulfonic acid methyl or ethyl esters in high yields the corresponding fluorine or chloroalkanes obtained if care is taken that the sulfur trioxide formed in the decomposition reaction is immediately intercepted by the formation of a connection and thus has no opportunity to the present to oxidize organic matter. According to the invention, alkali metal fluorides or -chlorides, which make the sulfur trioxide harmless by forming alkali halogen sulfonates.

One criterion for the effectiveness of the additives is the SO ₂ content of the gaseous reaction products. The higher the SO ₂ content, the greater the decomposition of the organic component. While the thermal decomposition of fluorosulfonic acid ethyl ester without additives, the gas formed consists of SO _{2 in} addition to a little ethylene, the SO _{2 is} in the decomposition in the presence of z. B. Potassium fluoride just barely detectable. The resulting SO ₃ is immediately bound as potassium fluorosulfonate by the potassium fluoride.

example 1

0.1 mol of fluorosulfonic acid methyl ester is heated to 180 ° C. for 1 hour with 0.5 mol of KF in a steel autoclave with a content of 250 ml. The yield of CH ₃ F is 82%. SO ₂ occurs only in amounts of

of fluorine- or chloroalkanes,

which have up to two carbon atoms

exhibit

Applicant:

Paint factories Bayer Aktiengesellschaft,
Leverkusen-Bayerwerk

Dr. Albrecht Zappel, Cologne-Stammheim,
and Dr. Heinz Jonas, Leverkusen,
have been named as inventors

2% of total sales. The solid residue consists of a mixture of KF and KFSO ₃ .

Example 2

0.3 mol of ethyl chlorosulfonate are heated without additives; after about 45 minutes at 150 ° C., sudden disintegration occurs. The temperature rises spontaneously to 210 ° C., about 50 percent by weight of the initial weight is found as a tarry residue. The gases collected and analyzed show that 41% of the sulfur used in the hexavalent state occurs as SO ₂ . Ethylene was formed to 36% and HCl to 66%. The ethyl chloride yield is only 6%.

Example 3

0.2 mol of ethyl chlorosulfonate are heated to 150 ° C. for 4 hours in the presence of 0.5 mol of KCl. _{C 2} H ₅ Cl is obtained in 65% yield. SO ₂ cannot be detected in the captured gas. The ethyl chloride cleavage into C ₂ H ₄ and HCl accounts for about 5% of the overall reaction. In a parallel experiment, the mixture is heated to 150 ° C. for 5 hours. The yield of C ₂ H ₅ Cl here is 86%.

Example 4

0.2 mol of chlorosulfonic acid ethyl ester are in the presence of 0.5 mol of NaCl for 1.5 hours Heated to 180 ° C. The trial balance is as follows:

48.6% undecomposed, 42% cleavage in C ₂ H ₅ Cl, 4% C ₂ H ₄ . SO ₂ cannot be detected.

209 609/411

Example 5

0.15 mol of ethyl fluorosulfonate are refluxed for 1 hour; Bottom temperature 115 to 120 ° C. There is no decomposition.

Example 6

As in Example 5, only in the presence of a small amount of Hg to accelerate the decomposition. Around 20% of the stake is recovered. Ethylene was formed to 31% and to 3 ° / »C ₂ H ₅ F. 56% of the sulfur used in the hexavalent stage is therefore found again as SO ₂ . The residue consists of a tar-like mass.

Example 7

As in Example 5, additionally 0.5 mol of KF are added. After one hour of heating at the 120 ° C. sump (reflux), 65% are still undecomposed, 18.6% of the feed has _{disintegrated in C 2} H ₅ F and 1.5% in C ₂ H ₄ .

SO ₂ was only formed in traces.

Example 8

As in Example 5, 0.5 mol of KF and a small amount of Hg were added. After 30 minutes of heating at 120 ° C., C ₂ H ₅ F was formed in about 50% yield, the proportion of C ₂ H ₄ is 10%, based on the ethyl fluorosulfonate used. The SO ₂ proportion is 2%.

Example 9

0.15 mol of ethyl fluorosulfonate are heated to a bottom temperature of 120 ° C. for 2 hours in the presence of 0.5 mol of NaF. The test balance has the following appearance: 31% undecomposed, 8.4% OS (OC ₂ H ₅ ) ₂ - by disproportionation of

FSO ₂ OC ₂ H ₅ -, 16.6% / o C,

H ₅ F and 7 * / o C,

SO ₂ cannot be detected.

'2 4 "

Claims (1)

PATENT CLAIM: Process for the preparation of fluorine- or chloroalkanes, which have up to 2 carbon atoms, by thermal cleavage of fluorine or fluoride. Methyl or ethyl chlorosulfonic acid esters, characterized in that the cleavage is carried out in the presence of an amount of alkali metal fluoride or alkali metal chloride sufficient to bind the sulfur trioxide formed during the cleavage. Considered publications:
German Patent Nos. 362 741, 740 677;
U.S. Patent No. 2,688,641. © 209 609/411 6.62