CS226026B2 - Method of preparing organic liquid polysulphides - Google Patents

Description

The invention relates to a process for the production of organic liquid polysulfides.

Known processes for the production of organic polysulfides are described, for example, in Polish Patent Specification No. 49,944 or in U.S. Patent Specification No. 2,466,963 et seq.

The main disadvantage of these processes is a considerable number of technological operations complicating the whole process. Considerable, though not complete simplification has been achieved, for example, by the method described in Polish patent specification No. 107 779. According to this method, the whole process consists of two steps. In the first step, the halogen atoms in the organic polyhalogen derivatives are replaced by thiol groups. In the second step, the polythiols obtained are oxidized by air oxygen to organic polymer disulfides while drying. Also, this method is complex and requires the use of several devices.

The disadvantages of the known processes are eliminated by the process for the production of organic liquid polysulphides from organic polynalogenic compounds and alkali hydrogen sulphide by the formation of polythiols by air oxygen according to the invention, which consists in the exchange reaction of halogen atoms in thiol groups and oxidation of the resulting polythiols to disulfide bonds. at the same time in a reactor equipped with an air supply to the reaction mixture.

The controlled oxidation of the polythiols is preferably carried out at a temperature in the range of 350 to 380 K.

(The occlusion of the polythiols is preferably carried out in the presence of a catalyst, namely iron, copper, chromium and other heavy metals, whose proportion in the reaction mixture amounts to 0.1% by weight, calculated on the dry weight of the alkali hydrogen fluoride used.

In the case of obtaining polytulphium with too low a degree of oxidized polythiols, its subsequent oxidation is carried out with hydrogen peroxide at a temperature of 310 to 350 K.

An advantage of the process according to the invention is that the organic polysulfides are obtained by a single step production. For this purpose, a mixture of polychlorinated compounds containing 95-100% of difunctional compounds and up to 5% by weight of higher functionality compounds is heated with stirring with an aqueous solution of sodium hydrosulfide. Heating is continued until the temperature reaches a degree lower by 10 to 20 K than the boiling point of the most basic component of the simes. The temperature reached is maintained at a constant level until about 90% of the Cl / SH exchange is reached. After reaching. At this stage of the exchange, air is introduced into the mixture and the temperature rises to about 375 K. At this stage of production, the thiol group content of the product obtained is regularly checked and after reaching the desired minimum temperature. oxidation stops.

Wrong product. is washed with water and dried at a temperature of approximately 353 K.

The processes occurring in the reactor and leading to the formation of polysulfides are catalyzed by iron compounds or by compounds of compounds, chromium and other heavy metals.

In carrying out the process of the invention, it has been shown that the rate of oxidation of thiol groups by air oxygen increases simultaneously with an increase in the concentration of iron compounds.

The concentration of chlorine or ferric sulphate in an amount of 0.1 percent by weight proved to be optimal.

The use of a high temperature of approximately 375 K in the final stage of the process for the production of polymeric polysulfides according to the invention makes it possible to obtain an oozi-chain bonded product, even when used as a reagent for. cross-linking utilizes a three or multifunctional halogen compound containing halogen atoms attached to the secondary carbon.

In some cases, when a polysulfide having a too low oxidation degree of polyol is obtained, the product obtained can be improved to the desired quality by oxidation with a hydrogen peroxide solution.

The solution was then held in the reactor at about 340 K.

The condition for obtaining the liquid polysulfides by the process of the invention is the need to use a liquid boiling point of about 400 K.

Example 1

Ь3,85 kg ⁽¹ 75 moles) tectoi-ckéto hydrogenoiUftou ut ^H t ^Copper was rozpuštono in ³⁰ voty turf ^3, characterized ignites ^kl solution in ^p Raven ^d sklenénéto reactor of capacity ^{100 d} m ³ and water ⁶⁰ toplnto ^d m ³ . ^p Otom ^b ^ t was added for the reactor ^8, 65 kg ⁽⁰ 5 mol) of ^2, 2 ^-i ic ^h lordiety ^ft OMLA ^benzaldehyde UA 148 g (1 mol) of 1,2,3-trihhtoppoopjmž.

A bypass was ignited and the reactor content was prevented to 340 K. The temperature of the reaction mixture continued to rise due to the exothermic reaction, and therefore regular cooling was used to maintain the temperature at 350 to 355 K for 6 hours.

After this time was involved in the air stream and was introduced into the lower three CSS reaction mixture mntotví ^ ibíl.itoě (DEG, 1 m ^{3 / h} with a gradual increase Tej ^ y during Todina ³ and ^z at 376 K, the temperature not exceeding The temperature was maintained at this temperature for 6 hours, while the mixture was stirred and air was introduced.

After ^{6 h,} was clothed ^EXAMPLE ITO ^to mod ^d uc ^h u raised to ^0, 5 m ^ / ^hr, and the ^P r: ITO ^{to be} L kept ^from OV ^o n for 2 hours, during which were collected sample time for analysis.

Upon reaching a thiol group of 3.1%, the oxidation was discontinued and the product obtained was washed. Washing was performed four times with water, but the third washing with ^{p Class} nírn about ³ dm @ ^t all ⁱ c ^{to k} Yssel _n ^{i s} c ^ o ^ orovodtové nccenraci I ^0%.

The washed product was placed in a vacuum dryer where it was dewatered at a temperature of 353 K and a pressure of 0.01 lvTa.

7.5 kg of sulphide with 2.9% SH and average molecular weight were obtained. The yield was 90% of theory.

Example 2 ‘.

The washed product, containing approximately 7% idol groups, was oxidized at 333 K with a 30% hydrogen peroxide solution in 4 dm 2. .

After determining the decrease in the content of thiol groups to 2.9%> hmoSnosti cool the reaction mixture and ^^^^ t ^{p s} and ROMs. PM third ^ o ^ tion was 1 m ^ ^d ^ crushed HCFC Semnyi HCl.

The product was dewatered as in Example 1. 7.3 kg of polysulfide having a content of 2.8% SH and an average molecular weight were obtained. 2 360.

The yield was approximately 89% of theory.

Claims (4)

CLAIMS 1. A process for the production of organic liquid polysulphides from organic psyl halides and alkali hydrogen sulphide by the formation of polythiols by air oxygen, characterized in that the exchange reaction of the halogen atoms in the thiol groups as well as the oxidation of the polythiols formed on the disulphide bonds are carried out. at the same time in a reactor provided with an air supply to the reaction mixture. 2. The process of claim 1, wherein the controlled oxidation of the polythiols is carried out at a temperature in the range of 350 to 380 K. 3. A process according to claim 2 wherein the oxidation of the polythiols is carried out in the presence of a catalyst selected from the group consisting of iron, mmdi, chromium and other heavy metals, the proportion of which in the reaction mixture is 0.1% by weight. of the alkaline hydrogen sulphide used. 4. The process according to claim 3, characterized in that in the case of obtaining a polysulphide having a low degree of oxidized polythiols, its subsequent oxidation is carried out with hydrogen peroxide at a temperature of 310 to 350 K.