PL176581B1 - Method of obtaining organic polysulphides - Google Patents

Abstract

A method of obtaining solid inorganic polysulfides by reacting elemental sulfur with an alkali metal or alkaline earth metal hydroxide dissolved in water, characterized in that the synthesis of polysulfide is carried out in the temperature range of 80-110 ° C, and the post-reaction mixture of polysulfide and thiosulfate with a molar ratio 2: 1, after separation of impurities and thiosulfate, it is subjected to concentration at 100-110 ° C until the crystallization of the final product starts.

Description

The present invention relates to a method for obtaining solid inorganic polysulfides.

Known methods for the preparation of inorganic polysulfides consist in sintering the appropriate metals or their carbonates with elemental sulfur in an inert gas atmosphere or attaching sulfur atoms to sulfide molecules.

The disadvantage of the methods based on sintering is the necessity to use high temperature, which is difficult to implement in practice, under the conditions of exo-energetic reaction, as well as the use of expensive inert gases, without which unfavorable by-products of the oxidation reaction are formed. The attachment of sulfur atoms to sulfide molecules requires their prior preparation, most often as a result of the reaction of the appropriate hydroxide with toxic and explosive hydrogen sulfide.

There are also known methods of obtaining aqueous solutions of alkali metal and alkaline earth metal sulphides in the form of mixtures, resulting from the reaction of elemental sulfur with hydroxides of these metals, containing polysulphides in addition to thiosulphates. These solutions are used, among others, for the production of precipitated sulfur, used in a pharmacy formula. In the past, it was used in the so-called "Californian liquid", which is a post-reaction solution of elemental sulfur with a suspension of calcium hydroxide.

The method according to the invention for obtaining solid inorganic polysulfides by reacting elemental sulfur with an alkali metal or alkaline earth metal hydroxide dissolved in water is characterized in that the polysulfide synthesis is carried out in the temperature range of 80-110 ° C, and the post-reaction mixture of polysulfide and thiosulfate with a ratio of 2: 1 molar ratio, after separation of impurities and thiosulphate, it is concentrated at 100-110 ° C until the crystallization of the final product starts.

The quantitative composition of individual components used to carry out the reaction is determined each time depending on what we want to obtain the final product.

The quantification is made on the basis of the reaction:

6M'0H + (2x + 2) S -> 2M ^! 2S _x + M ' ₂ S ₂ O ₃ + 3H ₂ O or

3M ⁿ (OH) 2 + (2x + 2) S -> 2M ⁿ Sx + M ⁿ S ₂ O ₃ + 3H ₂ O where M ¹ is an alkali metal,

M ¹¹ alkaline earth metal, x number of sulfur atoms in the molecule.

The method according to the invention is illustrated in the embodiments of the invention.

Example 1.

22 m ^{3 of} water was poured into the glass reactor and the stirrer was started, then 18.8 kg of sodium hydroxide was poured in batchwise. After its complete dissolution, the contents of the reactor were heated to 80 ° C and 25.1 kg of technical granulated sulfur were poured in portions over 1 hour.

176 581 while maintaining a temperature of 80-90 ° C. After completion of the addition the reaction temperature was raised to 100 - 105 ° C and maintained in this range for 2 hours, after which the reactor contents were cooled, added 18 m ³ of water and transferred to a container, allowed to stand for 10 days. After this time, the clear liquid containing sodium polysulfide was placed in a laboratory evaporator to remove water at a temperature of 100-105 ° C. After reaching the "saccharified honey" consistency, the contents of the evaporator were emptied by pouring it onto the internally cooled surface of an actuated rotary drum equipped with a scraper. 27 kg of solid sodium polysulfide with an average molecular formula of Na ₂ S _{4 were} obtained, which were placed in sealed glass jars.

Example 2.

650 cm3 of distilled water was poured into a glass beaker, mixing was started and 580 g of potassium hydroxide reagent was poured in portions. After its dissolution, the temperature was raised to 80 ° C and 466 g of sublimated sulfur were added in portions. The temperature was maintained at 80-90 ° C until the sulfur was completely dissolved and then increased for 2 hours to about 105 ° C. Thereafter, the contents of the beaker were cooled to 70 ° C and 350 cm3 of distilled water were added. The post-reaction solution was left for 1 day, after which the clear liquid was poured from the thiosulfate crystals and impurities and concentrated at 100-110 ° C until the "hot" crystallization reaction started. The thus obtained end product, in the amount of 540 g of potassium polysulfide with an average molecular formula K ₂ S 4 5, was transferred to a porcelain cuvette, and after cooling and crushing it was placed in tightly closed glass jars.

176 581

Publishing Department of the UP RP. Circulation of 70 copies

Price PLN 2.00.

Claims (1)

Patent claim A method of obtaining solid inorganic polysulfides by reacting elemental sulfur with an alkali metal or alkaline earth metal hydroxide dissolved in water, characterized in that the synthesis of the polysulfide is carried out in the temperature range of 80 110 ° C, and the post-reaction mixture of polysulfide and thiosulfate with a molar ratio of 2: 1, after separation of impurities and thiosulfate, is subjected to concentration at 100-110 ° C until the crystallization of the final product starts.