DE752572C - Process for the preparation of acetylsulfanilic acid chloride - Google Patents

Description

Issued on the basis of the VO. from 12.5.1943 - RGBl. II p. 15O

ISSUED JANUARY 4, 1954

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REICH'S PATEN OFFICE

& bik> theek Bur. InoL Eig

2 6 JAN 1954

PATENT LETTERING

CLASS 12 ο GROUP 23 03

C 56645 IVd 1120

Subsequently printed by the German Patent Office in Munich

(Section 20 of the First Act on the Amendment and Transition of Regulations in the field of industrial property protection from July 8, 1949)

Dr. Erich Haack, Radebeul and Dr. Robert Jacob, Radebeul

have been named as inventors

Chemical factory of Heyden A. G., Munich

Process for the preparation of acetylsulfanilic acid chloride

Patented in the German Reich from July 15, 1941. The period from May 8, 1945 up to and including May 7, 1950 is not counted towards the duration of the patent

(Ges. V. 7.51 / 15) Grant of patent announced on July 6, 1944

Acetylsulfanilsäurechlorid was previously mostly by reacting acetanilide with a large excess of chlorosulfonic acid produced. The chlorosulfonic acid works here in

first stage as a sulfonating agent, then as a chlorinating agent. The representation follows the two summary equations

C ₈ H ₉ ON + ClSO ₃ H> C ₃ H ₈ ON - SO ₃ H + HCl,

C ₈ H ₈ ON-SO ₃ H + ClSO ₃ HiZ ^ C ₈ H ₈ ON-SO ₂ Cl + H ₂ SO ₄ .

ίο The implementation according to (II) represents a balance the left side of which appears strongly preferred. There must therefore be a large excess of chlorosulfonic acid can be applied to obtain useful yields of acetylsulfanilic acid chloride to obtain. So z. B. specified,

that / ₀ are obtained crude Acetylsulfanilsäurechlorid when using a total of 5 moles of chlorosulfonic acid to 1 mole of acetanilide yields 77-81 °. In practical tests with about 100 g of acetanilide, an average of 5 moles is obtained

Chlorosulfonic acid a 76% yield if the yield of the rather easily decomposable sulfochloride is determined by its conversion in the stable and easy to test for purity acetylsulfanilamide. Even increasing the amount of chlorosulfonic acid does not bring any significant progress. Though should ■ the equilibrium be shifted further in favor of chloride formation; In fact however, with more than 5 moles of chlorosulfonic acid, only the same or even the same amount is obtained less-on; Sulfochloride, this determined as Sulfami'd. ' At the same time the violence is approaching the decomposition reaction with water or ice that of pure chlorosulfonic acid, see above that you have to use or forced to use significant amounts of ice or other coolants is. to remove the excess chlorosulphonic acid in another way.

It has now been found that one can practically achieve ioo _"o strength yields of Acetylsulfanilsäurechlorid when adding other than chlorosulfonic acid or another chlorinating agent under either with the resultant according to the equation (I) sulfonic acid or with the occurring according to equation (II) sulfuric acid Thionyl chloride, which is already known per se as a chlorinating agent for sulfonic acids, has proven to be particularly suitable Yield or move them to near 100 ⁰ Z ₀ .

The additional chlorinating agent can be added to the chlorosulfonic acid right from the start, or it can be added gradually to the sulfonation mixture after the acetanilide has been introduced into the chlorosulfonic acid. Since z. B. Thionyl chloride is quite volatile with hydrochloric acid gas, the latter process usually gives slightly better results or saves part of the thionyl chloride. ! The amount of additionally added CHIO j rierungsmittels optimally is 1 mole, calculated on j 2 implementable chlorine atoms, plus I entrained by the gas stream, and thus' lost for the chlorination amounts, ie. practically depending on the version 1.1 to | 1.5 mol. However, even smaller amounts of j increase the yields considerably, so that it; at times it may be economical to use less of the relatively expensive additional chlorinating agent.

The amount of chlorosulfonic acid can be from. not reduced arbitrarily for operational reasons j wi-rden. For example crystallized from a; Approach of 1 mol of acetanilide, 2.5 mol of chlorosulfonic acid. 1.5 mol of thionyl chloride the acetylsulfanilic acid chloride formed so far from that the mass is almost solid. An amount of 2.75 to 3 moles of chlorosulfonic acid proves but prove to be very useful.

ι moles of chlorosulfonic acid can also be replaced by other sulfonating agents, e.g. B. by sulfur trioxide in the form of fuming sulfuric acid. It is also possible in itself only to assume fuming sulfuric acid or sulfuric acid itself, if one more of the additional chlorinating agent, e.g. B. thionyl chloride applies. You get thus the same good results as with chlorosulfonic acid and chlorinating agents im corresponding molar ratio.

The advantage of the method according to the invention lies in the better utilization of the relatively expensive acetanilide, eliminating the need for a relative to chlorosulfonic acid more expensive chlorinating agent is justified, as well as in the higher performance of the Sulphonation plant, which reduces operating costs. A comparison of the yields according to the known and the here proposed process is given in the following table, with the yields of acetylsulfanilic acid chloride after. Conversion into the stable amide are determined. The actual Yields are thus even higher by the loss occurring in the amidation:

ClSO ₃ H 1.2 SOCl ₂ O yield Mole 1.3 Mole 0.1 a) ill _2 1.2 _ 0.5 a) O 3 1.2 - 1.0 a) 30th 4th - 1.5 a) 65 5 - up to 1.5 b) 76 6th - up to 1.5 b) 73 3.0 up to 1.5 b) 30th 3.0 up to 1.5 b) 42 3.0 62 3.0 78 3.0 & 7 2.5 /O 2.75 90 3.00 ₉ b 3.50 97

a) SOCl. from the outset of chlorosulfonic acid

ztigesi'tzt,
Ij) SOCL subsequently added dropwise.

example 1

150 g of technical acetanilide are slowly introduced into 357 g (-2.75 mol) of technical chlorosulfonic acid with thorough stirring, the temperature being allowed to rise to 40 ° and being obtained by cooling. After the entry, it is ^{heated to (> o J} until no further

Hydrochloric more escapes (about _^3/4 to ι hour). Technical thionyl chloride is then added dropwise at 60 ° until no significant evolution of hydrochloric acid and sulfur dioxide occurs (about 165 g of thionyl chloride = 1.25 mol). The mass is stirred until no more gases escape, cooled and poured onto 900 g of ice -j- 200 ecm of water while stirring. The separated sulfonic acid chloride is filtered off with suction, washed briefly with water and stirred into dilute ammonia. The washed and dried acetylsulfanilamide sucked in weighs 208 g, m.p.

When using 150 g of pure acetanilide, 390 g of chlorosulfonic acid (= 3.0 mol), 160 g of techn. Thionyl chloride (about 1.2 mol) is obtained 229 g (= 90.5 ",") acetylsulfanilamide with a melting point of 205 up to 2io °.

Good results are also obtained with 3 to 4 moles of chlorosulfonic acid and ₃ to 1.5 moles of phosphorus trichloride or 1 to 1.5 moles of graft pentachloride.

Example 2

150 g of acetanilide are introduced into a mixture of ι moles of SO ₃ (in the form of 6o ° / ₀ iger fuming sulfuric acid) and 1.5 moles of chlorosulfonic acid and heated to 60 ° for 1 hour; if it is now poured on ice, to obtain a yield of about 20 to 25 ° / ₀ sulfochloride. At 60 °, 1.5 mol of technical thionyl chloride are added dropwise and heated until no more gas escapes. The work-up then takes place as usual. Yield about 88 to 90% amide.

The thionyl chloride can also be replaced by pyrosulfuryl chloride, with one also can save some of the chlorosulfonic acid.

Claims (1)

Claim: Process for the production of acetylsulfanilic acid chloride from acetanilide and chlorosulfonic acid or oleum and chlorosulfonic acid, characterized in that, in addition to chlorosulfonic acid, to complete chlorination, there are other chlorinating agents of acid chloride character applies. To differentiate the subject matter of the invention from the state of the art, the granting process is in progress the following publication has been considered: German patent specification No. 499 052. © 5658 12.