In which fields is anhydrous sodium sulfite used?

Anhydrous sodium sulfite is used as a developing protective agent in the photographic industry; used in textiles for bleaching fabrics; used as a decalcifier in the leather industry; used as a preservative in the food industry, and mainly used as a reducing agent in the production of pharmaceutical preparations. The application examples are as follows:

1) Preparation of an acidic textile dye containing anhydrous sodium sulfite and dimethicone diquaternary ammonium salt, which belongs to the technical field of textile dyes. The acidic textile dye includes the following parts by weight of each component: 15-30 parts of acid dye, 5-10 parts of anhydrous sodium sulfite, 4-8 parts of sodium dihydrogen phosphate, 2-5 parts of sodium laurate, Polyvinyl alcohol 3-11 parts, wetting agent 1-5 parts, polydimethylsiloxane diquaternary ammonium salt 8-13 parts, polymethylcyclotetrasiloxane 3-9 parts, fatty acid sodium 2-9 parts, Acetic acid 1-6 parts. The invention ensures the dyeing ability of natural dyes on textiles, the dyed fabric has uniform color, and has excellent soaping fastness, sunlight fastness and bacteriostatic performance.

2) Preparation of foamed phenolic resin, especially the synthesis of a high-performance dehydration-free foamed phenolic resin. First use paraformaldehyde and phenol as raw materials and anhydrous sodium sulfite as a catalyst for polycondensation reaction, in which: the weight ratio of paraformaldehyde and phenol is 0.38~0.64:1, the weight ratio of anhydrous sodium sulfite and phenol is 0.03~0.08: 1. The weight ratio of water to phenol is 0.06~0.12:1; then use p-toluenesulfonic acid water and ethylene glycol or diethylene glycol or triethylene glycol or polyethylene glycol solution to neutralize the product of the above polycondensation reaction , Neutralizer: The weight ratio of p-toluenesulfonic acid to phenol is 0.03~0.05:1, and the weight ratio of ethylene glycol or diethylene glycol or triethylene glycol or polyethylene glycol to phenol is 0.04~0.12: 1. The weight ratio of water to phenol is 0.015~0.022:1. The invention eliminates the dehydration process in the synthetic production process, and has no waste water discharge in the entire production process, which is environmentally friendly and energy-saving, has high product performance, and is suitable for the production of high-quality phenolic foam.

3) Preparation of a dispersion-stabilizing agent using paper sludge, including dropping NaOH solution directly to raw materials without treatment, adding anhydrous sodium sulfite at a temperature of 90°C to react for 1.5 to 2 hours; then adding hydrogen peroxide, formaldehyde solution and no Water sodium sulfite reaction; finally add monochloroacetic acid and stir for 2~3h to obtain a dispersion-stabilizer containing sodium lignosulfonate-sodium carboxymethyl cellulose. The obtained product has very good dispersion stability. It can be used in coal water slurry to achieve a concentration of 67%, a viscosity below 1100mPa·s, no hard precipitation after 72 hours, and good fluidity. The process of the invention is simple, the reaction conditions are mild, and the reuse of waste is realized, and the invention can be used in industries such as preparation of coal water slurry, oil field, and cement processing.

4) Preparation of a monocyclic aromatic hydrocarbon type superplasticizer. This monocyclic aromatic hydrocarbon type superplasticizer uses anhydrous sodium sulfite, sodium sulfamate, acetophenone, bisphenol A and formaldehyde monomer as the main raw materials. First, using sodium hydroxide produced by the hydrolysis of partially anhydrous sodium sulfite as a catalyst, under alkaline conditions, acetophenone condenses with some formaldehyde and reacts with a compound sulfonating agent (sodium sulfamate + anhydrous sodium sulfite hydrolysate) Introduce amino and sulfonic acid groups onto the benzene ring to form the intermediate of the sulfonated formaldehyde-acetophenone condensation product. Then, under alkaline conditions, bisphenol A undergoes methylation reaction with another part of formaldehyde to form bisphenol A-formaldehyde intermediate, while the remaining hydrolysate of anhydrous sodium sulfite and formaldehyde are added in the middle of bisphenol A-formaldehyde phenolic The sulfonate is introduced in vivo. Finally, sulfonated formaldehyde-acetophenone condensation intermediate and sulfonated bisphenol A-formaldehyde intermediate are subjected to polycondensation reaction to synthesize monocyclic aromatic hydrocarbon type superplasticizer.