[Background and Overview][1][2]
Resorcinol is also known as 1,3-benzenediol. Common name is resin phenol. Molecular formula C6H6O2, colorless needle-shaped crystalline solid, melting point 110℃, boiling point 178℃, astringent taste, a little sweet , soluble in water, ethanol, and ether. It is easily oxidized and turns pink when exposed to air. It turns purple when encountering ferric chloride aqueous solution. Industrially, it is prepared by sulfonation reaction between benzene and concentrated sulfuric acid to generate isophenylene disulfonic acid, which is then eutectic with sodium hydroxide. It is widely used in the synthesis of dyes and drugs and is an important raw material for organic synthesis. For example, eosin is an important triphenylmethane dye that dyes bright red and is mainly used for dyeing silk. It is prepared by co-heating resorcin and phthalic anhydride in the presence of zinc chloride or concentrated sulfuric acid to prepare the intermediate fluorescence Yellow, obtained by tetrabromination.
Eosin is commonly used to make red ink and can also be used as a stain for microscopic examination of biological materials. If the intermediate fluorescent yellow is brominated in an acetic acid solution, only dibromination can be carried out, and then heated with mercury acetate to produce mercurochrome (also called mercury bromide), which is an important disinfection preservative. It is easily soluble in water, and a 2% aqueous solution is the "red potion" used for daily sterilization and disinfection. An alcohol-acetone solution of mercurochrome can also be used for skin disinfection. 4-n-Hexylresorcinol can be produced by acylation and reduction of resorcinol and hexanoic acid, which is also a disinfectant. It is also used in medicine as a local anti-itching agent and intestinal digestive agent.
[Indications][3]
Used to treat ringworm, eczema, seborrheic dermatitis, acne and psoriasis.
[Specifications][3]
Ointment, lotion, lubricant or ethanol solution: 2% ~ 5%.
【Usage and Dosage】[3 ]
Topical application: 2% to 5% lotion, lubricant, alcohol solution or ointment.
[Pharmacological effects][3 ]
This product has bactericidal, fungicidal and antipruritic effects. Its bactericidal effect is 1/3 of phenol, and its irritation and corrosiveness are also less. Low concentration promotes keratin regeneration, while high concentration has keratin exfoliation effect.
[Adverse reactions][3 ]
1. It is weakly irritating to the skin and mucous membranes; absorbed through the skin, ulcer surface or prolonged action, causing myxedema.
2. Due to the anti-thyroid effect of this product, the systemic reaction is similar to phenol poisoning, but convulsions often occur.
3. It can also cause contact sensitization reactions.
[Drug Interaction][3]
1. It is not compatible with ethyl nitrite, iron salt, and caustic alkali.
2. When ground together with camphor, menthol and phenol, it can be liquefied or agglomerated.
[Notes][3 ]
This product cannot be used all over the body or for a long time. It should not be applied to broken skin to avoid absorption and poisoning.
[Other applications][2][4]
Resorcinol is used as a raw material for dyes and plastic synthetic fibers, and is used in industries such as rubber tire cord dipping, resin, film, agricultural film and explosives.
1. Organic chemical raw materials
Resorcinol is used in organic chemical raw materials such as synthetic celluloid, tannic acid, p-aminosalicylic acid, m-chlorophenol, trinitroresorcinol, etc. Its derivatives are raw materials for many fine chemicals.
2. Rubber and tire industry
Most resorcinol is used in rubber adhesives. Mainly used in tire cord (cloth). Resorcinol, formaldehyde resin and resorcinol, formaldehyde and vinylpyridine synthetic resin are used as adhesives in the tire industry. Resorcinol is consumed in large quantities in domestic cord (cloth) production. In addition, domestic chemical fiber factories and cotton spinning mills also need resorcinol.
3. Adhesion accelerator
Adhesives are widely used in my country and are used in rubber, plastic elastomers, wood (laminated wood), light metals, ceramics, textile materials, fibers, papermaking (laminated paper), etc., especially in roof structures. , hull structure, etc. require a large amount of adhesives. For example, resorcinol and formaldehyde resin can be used to produce adhesives for various materials. With the popularity of high-end furniture, these adhesives can replace urea series adhesives, and demand is expected to grow.
4. Agriculture
Resorcinol can be used to synthesize agricultural films, as well as insecticides (pyrifosin) and herbicides (ethoxyfluorfen).
5. Dyes
Resorcinol is used to synthesize fluorescent dyes and acid eosin. It can also be mixed with catechol, amines and oxidants to be used as fur dyeing and hair dye. In addition, resorcin can also be used to produce plasticizers, stabilizers, detonators such as trinitroresorcin, etc.
【Preparation】 [5] [6]
Catalytic hydrolysis to synthesize resorcinol:
First, pour 0.375mol sulfuric acid (15%) into the capacity of 500mL four-necked bottle, while stirring, add 0.25 mol m-aminophenol until its temperature reaches 40°C. After the dissolution is completed, lower the temperature to 1°C to 5°C and set aside.
Secondly, pour 0.32 mol nitrite, 1.84 mol water, and 0.32 mol ethanol into a 250 mL flask, stir, and slowly drop 0.16 mol sulfuric acid (40%) into it to generate ethyl nitrite.
Third, pour 0.93 mol copper sulfate aqueous solution (30%) and 2 mol MIBK into a 2000 mL flask until the temperature rises to 85°C to 88°C, drop the diazo liquid, and keep the solution at this temperature for 2 hours to 3 hours, then lower the temperature to between 40°C and 50°C, and then let it stand until the oil layer and water layer separate. The water layer was placed in ice water for 4 hours until it crystallized. The copper sulfate crystals were filtered out, and the filtrate was extracted and separated using 0.5 mol MIBK. The extracted oil layer and the reflected oil layer are combined and processed. Activated carbon is added to the extracted water layer for decolorization. After concentration, it is used as a copper sulfate aqueous solution.
Fourth, pour the extracted oil layer into a 250mL four-necked flask, stir to raise the temperature to 100°C to 120°C at steam temperature, or 110°C to 130°C at kettle temperature, and desolvate under normal pressure. Then continuously add the extraction oil layer dropwise, and cool down the kettle when the temperature rises to 200°C. Under the action of nitrogen, the vacuum degree is maintained between 7.5 and 8.0 kPa, the temperature is maintained at 157°C to 206°C at steam temperature, or 198°C to 299°C at kettle temperature, and the decoking procedure is carried out to remove the coke. The coke fraction is collected. Under the condition of constant vacuum and pressure, use a 0.5-meter glass packed distillation column and keep the temperature at 187°C to 194°C at steam temperature or 200°C to 300°C at kettle temperature. The main fraction obtained is m-benzene Diphenols.
[Main reference materials]
[1] Social Dictionary of Science and Technology·Chemistry
[2] Technical Dictionary of Container Transport Business·Volume 2
[3] Practical Drug Handbook
[4] Zhang Wei. Resorcinol[J]. Fine Petrochemicals, 1995 (6): 79-80.
[5] Ge Qianyun. Analysis of catalytic hydrolysis to synthesize resorcinol[J]. Chemical Industry Management, 2017 (15): 136-137.
[6] Cui Jianxin. Research on the synthesis of resorcinol from isophthalic acid[D]. Tianjin University of Technology, 2007.
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