Sodium hydrosulfide

Sodium hydrosulfide is used in the dyestuff industry as a synthetic organic intermediate and an auxiliary in the preparation of sulfide dyes, in the tanning industry for the dehairing and tanning of raw hides, in the fertilizer industry for the removal of monomeric sulfur from activated charcoal desulfurizers, in the mining industry for large quantities of copper ore beneficiation, in the production of man-made fibers for the dyeing of sulfurous acid, etc., as a raw material for the manufacture of ammonium sulfide and semi-finished products of the pesticide ethanethiol, and also for the treatment of wastewater and so on. Sodium hydrosulfide production process is relatively mature, but with the development of a variety of economic forms and the increasingly fierce competition, the requirements of the lowest possible inputs and produce high-quality, more products. At present, the preparation method of sodium hydrosulfide is caustic soda absorption method, which requires the raw material gas to be pure hydrogen sulfide gas, mainly using the tail gas of barium chloride or barium nitrate production and sodium hydroxide solution reaction to produce sodium hydrosulfide. Caustic soda method of sodium hydrosulfide production requires that the raw material gas does not contain carbon dioxide, if the raw material gas contains carbon dioxide, in the production process there will be sodium carbonate generation: NaOH + CO2 → Na2CO3 + H2O, the generation of sodium carbonate not only reduces the yield of caustic soda, but also affects the quality of sodium hydrosulfide, affecting the use of the user, the content of carbon dioxide is greater than 10%, the production of carbon dioxide will also be blocked equipment and piping, so that the production can not be normal. If the content of carbon dioxide is more than 10%, it will block the equipment and pipeline in the production, and the production can not be normal.

Application

Sodium hydrosulfide is an important raw material for sulfhydrylation reaction, which is widely used in organic synthesis and industrial production. For example, it is used in the dyestuff industry for the synthesis of organic intermediates and as an auxiliary in the preparation of sulfide dyes. It is used in tanning industry for dehairing and tanning of raw hides, and also used in waste water treatment; it is used in fertilizer industry for removing monomer sulfur in activated carbon desulfurizer. It is the raw material for manufacturing ammonium sulfide and semi-finished products of pesticide ethanethiol. It is used in large quantities for copper ore dressing in the mining industry. Synthetic fiber production for sulfite dyeing and other aspects.

(1) with sodium hydrosulfide reduction production of 2-amino-4-acetylaminophenyl alkyl ether method, it is in the quality of the reactants 3-5 times the water added 2-nitro-4-acetylaminophenyl alkyl ether, add glacial acetic acid, with liquid alkali to adjust the material to pH = 5 ~ 6; temperature to 90 ~ 105 ℃, drop 10 ~ 25% sodium hydrosulfide solution, drop than, at the temperature of the holding reaction for 1 hour; slow Cooling so that the product crystallization precipitation, filter out the crystals, cold water wash the crystals to the filtrate pH = 7, that is, 2-amino-4-acetamidophenyl alkyl ether, wash water set to the next batch of reduction use. The advantages of the present invention are: (1) high reaction yield, the yield is above 90%; (2) fast reaction speed, so that the product is not easy to oxidize, the product color is good quality; (3) no need for complex post-processing, equipment and operation is simple; (4) less wastewater, easy to deal with, it's a low-emission clean process; (5) so that petrochemical and other industries recycling treatment of hydrogen sulfide exhaust gas and get sodium hydrosulfide solution to achieve the use of resources and low cost.

(2) Sodium hydrosulfide mitigation of CdSe/ZnS quantum dots biotoxicity, the use of sodium hydrosulfide to mitigate the biotoxicity of CdSe/ZnS quantum dots to plants, animals or microorganisms. The method of the present invention has the advantages of simplicity, feasibility, convenience, and easy accessibility of a single reagent required, and the sodium hydrosulfide employed therein is capable of sulphurizing with heavy metal ions released from CdSe/ZnS quantum dots, which reduces the release of heavy metal ions, thus reducing the biotoxicity induced by the quantum dots; at the same time, the sodium hydrosulfide is capable of ionizing thioglycolide ions in an aqueous solution, generating hydrogen sulphide through hydrolysis which improves the cellular activity of the organism and can alleviate the oxidative stress on the organism produced by unfavorable factors in the environment; thus, the present invention using sodium hydrosulfide can alleviate the biotoxicity of the CdSe/ZnS quantum dots to the plants, animals, or microorganisms, and it can be widely used in the biomedical applications.

(3) Method of preparing polyaryl sulfide with sodium hydrosulfide at atmospheric pressure by reacting sodium hydrosulfide with a base and a polyhalogenated aromatic compound at atmospheric pressure in a polar nonprotonic solvent. The use of multi-component composite catalyst or reaction aids (the main component is LiCl, etc.), sodium hydrosulfide: halogenated aromatic compounds (mol) = 1: (0.5 ~ 2), sodium hydrosulfide: catalyst (mol) = 1: (0.03 ~ 1), sodium hydrosulfide: base = 1: (0.9 ~ 1.6). The reaction was 140°C~350°C for 2~12 hours. The yield of polyaryl sulfide is up to more than 90%, the weight average molecular weight is 56,000, the product is white, high thermal stability, good mechanical properties.

(4) the method of preparing 2,2'-diaminoethylene glycol diphenyl ether by reduction with sodium hydrosulfide, add 1,2-bis(2-nitrophenoxy)ethane, water, sodium hydrosulfide aqueous solution to the autoclave, pass nitrogen replacement, raise the temperature, control the reaction pressure of 0-0.5Mpa, reaction temperature of 100-140 ℃, keep warm for 2-6h, end of the reaction; the reaction is completed. After the reaction is completed, the pressure is discharged, the temperature is lowered, and the product is filtered at 30-35°C to obtain the crude product. The crude product is solvented with water, refined by acid solubilization and alkali counter-adjustment, and dried to obtain qualified products. The use of water as a solvent, do not use alcohols and other organic solvents, the reaction yield is greater than 90%, product purity is greater than 99.5%, the reduction of wastewater produced only sodium hydrosulfide and sodium thiosulfate, through the oxidation of sodium hydrosulfide into sodium thiosulfate, recovery of sodium thiosulfate, evaporation of water for the set of use, it is a green process; equipment requirements are low, less investment.

(5) The new use of sodium hydrosulfide to promote the germination of wheat seeds under heavy metal stress is the application of sodium hydrosulfide as a germination promoter for wheat seeds in soil contaminated by heavy metals such as Al3+, Cd2+, Cr3+, Cr6+, Pb2+, Hg2+, and so on. The present invention can effectively improve the germination potential of wheat seeds under heavy metal stress and induce rapid and neat seed germination. The study shows that pretreatment of wheat seeds with the present hydrogen sulfide donor sodium hydrosulfide can significantly induce the expression of the activity of hydrolytic enzymes such as amylase, protease, lipase and other hydrolytic enzymes in the seeds, promote the oxidative decomposition of the storage material, alleviate the oxidative damage induced by heavy metal stress within the seeds, and maintain a lower level of membrane lipid peroxidation within the seeds and seedlings, thus facilitating the normal growth of the germination and the root of the embryo. The present invention solves the key problems in restoring wheat production in heavy metal contaminated areas, and the operation is simple and the required reagents are single and easy to obtain.

Preparation

Sodium hydrosulfide is made by absorbing hydrogen sulfide with liquid alkali. The reaction formula is given below:

NaOH + H₂S = NaHS + 2H₂O

The absorption process of sodium hydrosulfide takes place under negative pressure and the reaction is essentially a two-step process, starting with the absorption of hydrogen sulfide by sodium hydroxide to produce sodium sulfide:

2NaOH +H₂S = Na₂S +2H₂O

When the absorption of sodium sulfide is saturated, it continues to absorb hydrogen sulfide to produce sodium hydrosulfide:

Na₂S + H₂S = 2NaS

Caustic soda absorption of hydrogen sulfide is carried out in the gas-liquid phase, a molecule of H2S and a molecule of caustic soda reaction, the reaction rate is fast, when the sodium sulfide is close to saturation, due to the formation of crystals, and the reaction is viscous, the mobility is greatly reduced due to the heat of the reaction so that the temperature of the solution increases, at this time, the reaction rate is greatly slowed down, the sodium sulfide absorption of hydrogen sulfide is also slower than the previous section, to the sodium hydroxide is close to saturation, the reaction rate is slower! Often H2S gas can not be completely absorbed.