DD142187A1 - CLEANING OF ALKANDISULOF CHLORIDES - Google Patents

Abstract

Process for the purification of alkanedisulfochlorides under low Expense of dark resinous products. It should receive products whose quality is suitable for polycondensation reactions. This is achieved by adding the in organic solvents dissolved crude products with small amounts of anhydrous AICI3 at treated at elevated temperature and deposited in this way Separates impurities. Subsequently, the pure product crystallized.

Description

21 ί

Title of the invention

Purification of alkane disulfide chlorides

Field of application of the invention

The invention relates to a process for the purification of alkanedisulfochlorides prepared by sulfochlorination of low molecular weight paraffin hydrocarbons »

Characteristic of the known technical solutions

In the sulfochlorination of paraffins, both alkane mono- and alkane disulfochlorides are formed. In the sulfochlorination of the CU-Cc paraffins Mo.nosulfochloride can be separated by distillation. The disulfochlorides remain as distillation residue, since their thermal instability does not allow distillation, even under reduced pressure. This distillation residue containing the disulfochlorides is considerably contaminated, in particular by dark, resinous products, so that the alkanedisulfonyl chlorides must be purified before further processing.

It is known that the alkanedisulfochlorides of propanes and

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Isobutan through. Crystallization of the distillation residue from CHCl., / CCl.-mixtures to be cleaned, the residue in CHCl., Is dissolved and the disulfochlorides after addition of larger amounts of CCl. Crystallization and cooling crystallize out (1) · Likewise, a similarly carried out crystallization from benzene and n-heptane has been described (2) · Significant disadvantages of these cleaning operations are that the dark, resinous products are separated in this way only insufficient, the crystallizations multiply are repeated and very large amounts of solvent are needed, which can not be recovered by distillation in pure form.

Furthermore, cyclopentadisulfochloride is known by taking up the distillation residue in ether, distilling off the ether from the solution thus obtained and then recrystallizing the residue obtained by dissolving in ether and precipitating with CCl. (3) to clean. The recrystallization must be repeated several times if a satisfactory cleaning effect is to be achieved. This process is complicated by the large number of operations and the high Lö-Bungsmittelbedarf and thus uneconomical. Furthermore, the propane-1,3-disulfochloride was directly from the reaction mixture of the sulfonation of propane in CCl. Although the extent and nature of the impurities of the propane-1,3-disulfochloride differ from those of the disulfochloride separated by distillation, purification by crystallization is still required. In addition, the deposition of propane-1,3-disulfochloride in the freezing is only incomplete and requires a lot of energy,

It is hinaus.bekannt about to separate the mono- and Disulfochloride the propane by steam distillation (5) _t without causing the impurities and thus also the cleaning effort for the propane-1,3-disulfoehlorid been changed

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would. There are only additional losses due to hydrolysis of the sulfochloride.

Object of the invention

The aim of the invention is to liberate by low cost of all impurities, in particular dark, resinous products produced by sulfochlorination and separated by distillation of monosulfonyl chlorides and in a suitable quality for polycondensation reactions.

Explanation of the essence of the invention

It was therefore the task of developing a process for the purification of low molecular weight alkanedisulfochlorides obtained by sulfochlorination, which makes it possible to produce alkanedisulfochlorides in high purity with low labor and material costs.

This object is achieved by a method for purifying prepared by sulfochlorination and separated by distillation of Alkanmonosiilfochloriden Alkandisulfochloriden according to the invention that the residue taken after the separation by distillation of alkane monosulfonyl chlorides in an organic solvent and by treatment of the resulting solution with small amounts of AlClIo at elevated Temperature the impurities are aggregated and separated. The subsequent addition of adsorbents or filter aids the cleaning effect can be improved. In the method according to the invention, a solution of a crude, low molecular weight alkanedisulfonyl chloride in an organic solvent at slightly elevated temperature is treated with small amounts of AlCl.sub.3. AlCly amounts between 0.1 and 5% by mass, in particular those between 0.2 and 0.5% by mass, based on the amount of alkanedisulfochloride used for the purification, are sufficient.

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proved. Surprisingly, according to the process of the invention, no desulfurization of the sulfonyl chloride occurs, but agglomeration and separation of the impurities, in particular the substances causing the dark color of the disulfochloride, in the form of a filterable precipitate in which the AlCl, or its hydrolysis products, are present.

After the treatment of the alkanedisulfochloride in solution with anhydrous AlCl.sub.i by the addition of filter aids or adsorbents, for example of Al.sub.2O.sub.4 or bleaching earth, in a quantity of up to 5 .mu.m (based on the alkanedisulphochloride), the cleaning effect can be achieved improved and the filtration of the deposited impurities are facilitated. The filter aids can be regenerated by extraction with acetone.

According to the inventive method, the treatment of the solution of Alandisulfochlorids at temperatures between and 70 ⁰ C, preferably 35 to 50 ⁰ C, are performed.

According to the process of the invention, halogenated hydrocarbons or hydrocarbons themselves, in particular aromatic hydrocarbons, can be used as the solvent for the crude residue contaminated with dark substances and obtained as the distillation residue. Especially suitable solvents _CHCIo: and mixtures of CHCl and CCl ^ .. G _s mix of CHCl3 and CCI. with 70 to 90 Ma, -%, preferably 75 to 85 Ma, -%, CHCl ^ are particularly advantageously used because of the significant difference in the solubility of alkanedisulfonyl chlorides at higher and lower temperatures and the possible with little distillative effort recovery of such a mixture of practically constant composition,

According to the process according to the invention, all crystallizing disulfochlorides of low molecular weight paraffin

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Purify hydrocarbons, in particular propane-1,3-disulfochloride. For the propane-1,3-disulfochloride is usually sufficient a one-time cleaning process to obtain white, pure melting point products. ,

From the treated with AlCl ^, possibly with filter aids, filtered solutions of Alkandisulfochloride in an organic solvent crystallizes that Alkandisulfochlorid on cooling to 0 to 5 ⁰ C, so that 80 to 85 Ma .-% nines disulfochloride can be isolated, A / veiterer part of Cisulf ochlorids can be obtained from the mother liquor after the distillation of the solvent, said disulfide is expediently recrystallized again by the process according to the invention,

EXAMPLES Example 1

.100 g of crude propane-1,3-disulfochloride (Pp 43 ⁰ C) were dissolved in 300 ml of a mixture of 85 Ma .-% CHCl ^ and 15 Ma .- ^ COl ^ under heating to 40 ⁰ C and the like solution obtained, also at 40 ⁰ C, 0.2 g of anhydrous AlCl ^ added with stirring and the mixture stirred for about 15 minutes. The dark gray-brown color of the solution changes to pale yellow and a reddish brown mud was separated. This sludge was filtered off. From the filtrate crystallized at 5 ⁰ C 84.5 g of propane-1,3-disulfochloride, color light gray to white, mp 47.5 ⁰ C Example 2

100 g of crude propane-1,3-disulfochloride (mp. 38 to 42 ⁰ C) .-% CHC1- in 300 ml of a mixture of 85 mA, and 15% by mass of CGI. dissolved with heating to 45 ⁰ C and the resulting solution, also at 45 ⁰ C, 0.2 g of anhydrous AlCl, added with stirring and the mixture stirred for about 15 minutes. The color of the solution changes from dark

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pale brown to light yellow and a reddish brown mud was deposited. To facilitate the filtration, 1 g of CaO was then added to the mixture and stirred again for about 5 minutes. The mixture was then filtered and the filtrate was crystallized at 0 ^° C. It could 86.5 g of propane-1,3-disulfochloride, color white, Pp. 47.5. to be 48.

C, isolated

Example 3 to 5

Working method cf. Example 2

example

Propane-1,3-disulfochloride crude

Quantity in g

Mp ⁰ C solvent CHCWCCl. Mixture

ml

Ma. -% CHCIo

AlCIo, anhydrous, amount in g temperature ⁰ C treatment time, minutes filter aid Art

Quantity in g

Crystallization at ⁰ C propane-1,3-disulfochloride isolated

Quantity in g

Mp.

colour

3 4 5

100 100 1000 37-42 37-42 38-43

300 1 500 8th White 2000 85 2 70 0 88 5 82.5 0.1 75 0.5 35 35 47.5-48.5 47.5 45 10 15 White 15 Al ₂ O Pale Al ₂ O ₃ earth 50 3 829 47-48 White

1) F. Asinger a. Employee: Chem. Bar · 75 (19 ^ 2), «34

DE-PS 717 680. · · - ·

2) F. Asinger u. Employee: Chem. Ber. 89 (1956) ».1100-10

3) U.S. Patent 3,238,255. ·

4) G. Geiseler u. Employee: Chsm. Ber. 91 (1958), 1512-15

5) DD-PS 3724

Claims (4)

-7- 211 246 Inventions claim 1 _# Process for the purification of sulfonylation of low molecular weight paraffins synthesized and separated by distillation of the monosulfonyl chlorides Alkandisulfochloride, characterized in that the residue taken after the separation by distillation of Monosülfochloride in an organic solvent and the resulting solution with 0.1 to $ Ma. -%, preferably 0.2 to 0.5% by mass of anhydrous aluminum chloride, based on the crude Alkandisulfochlorid offset ': and the impurities be ± elevated temperature aggregated with stirring and be deposited. 2. The method according to item 1, characterized in that the deposition of the impurities of Alkandisulfochloride by the addition of filter aids, preferably AIpOo supported. 3 # Method according to item 1 and 2, characterized in that the treatment of the solution of Alkandisulfochloride ⁰ C with AlClO at temperatures between 20 and 70 ⁰ C, preferably between 35 and 50 ⁰ C, is performed. 4. The method according to item 1 to 3, characterized in that hydrocarbons and halogenated hydrocarbons, preferably mixtures of CCl and, are used as the solvent.