DE124407C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

The sulfonic acid chlorides of the aromatic series are special in technical terms some orthosubstituted derivatives of particular importance for saccharin manufacture; in The o-toluenesulphonic acid chloride is primarily used and the o-sulfochloro-benzoic acid esters into consideration.

The ο - toluenesulfonic acid chloride is known to be either from o-toluenesulfonic acid by means of phosphorus pentachloride or from toluene by means of chlorosulfonic acid. The pure o-Toluenesulfonic acid is difficult to access; therefore the toluenesulfonyl chloride was used for the Saccharin manufacture from a lot of para-containing o-toluenesulfonic acid by means of phosphorus pentachloride shown, whereby of course a mixture of p- and o-toluenesulfochloride was obtained. A mixture of p- and o-toluenesulfonyl chloride is also obtained from toluene and chlorosulfonic acid.

The o-sulfochloride benzoic acid ester can obtained from o-sulfobenzoic acid by the process of patent 96125. the Presentation of the ο - sulfobenzoic acid is cumbersome.

It was now known through the work of Otto (Liebig's Annalen 141, pp. 372 and 374), that benzenesulfinic acid with bromine to form benzenesulfonic acid bromide and furthermore that benzenesulfinic acid with phosphorus pentachloride to form benzenesulfonyl chloride reacts. But that these reactions do not simply apply to all sulfinic acids The experiment by Limpricht and Heffter, which is known in this regard and which consists of p-amidotoluenesulfinic acid, shows with bromine not the corresponding sulfobromide, but the sulfonic acid, and with phosphorus pentachloride indefinable products received (Liebig's Annalen 221, pp. 34g and 350). Phosphorus pentachloride is not at all suitable for this, not even for representation of benzene sulphonyl chloride, because first of all by-products arise (Liebig's Annalen 141, P. 376) and, secondly, the sulfinic acid must be cleaned and dried, which is important Losses are associated, since the sulfinic acids decompose during storage. the The use of bromine in technology is avoided if possible because of the price because.

It was also mentioned by Otto and Tröger (Ber. D. D. former Ges. 24, 478) that at the action. from chlorine to benzenesulfinic acid Sodium, sodium chloride and benzenesulphochloride are formed. More details about this reaction are not known. But since Otto and Tröger are citirling Treatise state that iodine is quite analogous to the alkali salts of sulfinic acids if it behaves, one must come to the conclusion that chlorine and benzenesulphonic acids! sodium it did not react smoothly either, for when iodine acted on the sulfinic acid salt from Otto and Tröger approx. 56 pCl. the calculated amount of sulfoiodide received.

In fact one gets from benzenesulfinic acid as well as from its salts when treating them with a weak stream of chlorine, especially on a large scale, in addition to sulphochloride a lot of benzenesulfonic acid.

Claims (1)

After all that one could not predict whether with chlorine the corresponding o-substituted sulfonic acids are obtained from the possible Sulfochlorides obtained / are obtained in a satisfactory yield can. It has now been found that the o- TÄluolsulfonsäurechlorid and the ο - Sulphoehl ^; gridbenzoic acid ester in a smooth manner .the o-toluenesulfinic acid respectively. from the o-sulfinob.er/zoic acid esters can get by / These sulfinic acids under certain conditions, as such or in the form of their salts with chlorine .. treated. ¹ If a very strong stream of chlorine is introduced into an aqueous solution of an alkali metal salt of o-toluenesulfinic acid or o-sulfinbenzoic acid ester, the corresponding sulfochlorides are formed smoothly. If the sulfinic acids are substituted from the aqueous solutions of the salts with mineral acids in freedom and also introduces a very rapid flow of chlorine into the suspension, such as one can obtain such a bomb from a bomb filled with liquid chlorine with elimination of hydrochloric acid, the sulfonic acid chlorides also in an almost quantitative manner. When chlorinating the sulfinic acids mentioned respectively. One must absolutely have to use their salts in the large work with liquid chlorine to get good yields of chlorides. The representation of the o-ToIuolsulfonsäurechlorides and the o-sulfochloride benzoic acid ester is from the corresponding sulfinic acids very important from a technical point of view, since these compounds only contain o-derivatives can get pure saccharin immediately. The sulfinic acids to be used as starting material for the preparation of the sulfonic acid chlorides can be prepared from the corresponding diazo compounds and sulphurous acid. Example I. ίο kg of o-toluenesulfinic acid are diluted in Sodium hydroxide solution and introduced chlorine into this solution as quickly as possible until nothing fails anymore; the deposited oily toluenesulfonyl chloride becomes after cooling the liquid warmed up by chlorination separated by decantation, washed with water and processed on toluenesulfamide. The toluenesulfonyl chloride can also be prepared in such a way that the above solution of the sodium salt of sulfinic acid is mixed with hydrochloric acid and a rapid stream of chlorine is passed through the liquid in which the sulfinic acid is partly dissolved and partly suspended; the liquid heats up more or less depending on the strength of the chlorine flow. It regulates the flow of chlorine so that liquid DAF not warmer than 35 to 40 is ^0. Example II. The o-sulfinbenzoic acid methyl ester obtained from anthranilic acid methyl ester (melting point 98 to 99 ° C.) is dissolved in the necessary amount of aqueous alkali and treated with chlorine as in Example I. The methyl sulfochloride benzoate obtained in this way melts at 64 to 65 ^° C. Ρλ τ ε nt-claim: Process for the preparation of ο -Toluenesulfonic acid chloride and o-Sulfochloridbenzoic acid esters, consisting in the fact that the aqueous solution or suspension of the corresponding Sulfinic acids respectively. their soluble salts treated with a strong stream of chlorine.