The 4-hydroxybiphenyl market is highly concentrated and has broad development prospects.

​ ​ 4-Hydroxybiphenyl, also known as p-hydroxybiphenyl, p-phenylphenol, biphenyl-4-phenol, etc., appears as an off-white flaky solid and is an important chemical intermediate. 4-Hydroxybiphenyl products are easily soluble in organic solvents such as alcohols, ketones, and ethers and alkaline solutions, and are almost insoluble in water.

There are two main methods for preparing 4-hydroxybiphenyl, namely sulfuric acid sulfonation process and sulfur trioxide sulfonation process.

The sulfonation process of sulfur trioxide is as follows: dissolve biphenyl in acetic acid, sulfonate it with sulfur trioxide, separate the sulfonation product and react with 20% NaOH aqueous solution to form a salt, and then fuse it with solid NaOH in alkali at 100~350°C, and then Acidification is performed to obtain 4-hydroxybiphenyl product.

The sulfonation process of sulfuric acid is: react biphenyl with 98% sulfuric acid to generate biphenyl sulfonic acid, add water to dilute it, add NaOH to generate sodium biphenyl sulfonate, obtain solid sodium biphenyl sulfonate after separation, and then react with molten NaOH Sodium biphenolate is obtained, and 4-hydroxybiphenyl wet product is obtained through acidification. After drying, a crude product is obtained, and the crude product is refined to obtain 4-hydroxybiphenyl finished product.

4-Hydroxybiphenyl can be used to further synthesize red light sensitizing and green light sensitizing dyes; it can also be used as analytical reagents for colorimetric determination of acetaldehyde and lactic acid, quantitative determination of muramic acid, deoxyribonuclease inhibitors, and Intermediates for pesticides, resins, rubber, and solubilizers for water-soluble paints. But at this stage, 4-hydroxybiphenyl products are mainly used to produce the pesticide biphenyl hydrazine ester technical material.

Diphenylhydrazate is a new type of selective foliar acaricide. Its good acaricidal properties and high safety are gradually being recognized by the market. In recent years, with the continuous development of agricultural modernization and the strong support of the national zero-growth policy for pesticides, my country’s high-quality pesticide industry has continued to develop, its technical level has continued to improve, and its industrial scale has continued to expand, creating a good environment for the development of the 4-hydroxybiphenyl industry. Market demand conditions have promoted the continuous expansion of the scale of my country’s 4-hydroxybiphenyl industry. According to the “2023-2027 4-Hydroxybiphenyl Industry In-depth Market Research and Investment Strategy Suggestions Report released by the Industrial Research Center , China’s demand for 4-hydroxybiphenyl will reach about 2,000 tons in 2022.

Foreign countries have begun to research and produce 4-hydroxybiphenyl since the 1970s. Before 2000, the world’s major 4-hydroxybiphenyl manufacturers included Dow Chemical Company of the United States, Coal Chemical Products Company of the United Kingdom, and Bayer of Germany. China’s 4-hydroxybiphenyl started late, with more than 100 tons of production equipment only at the end of the 20th century.

Industry analysts said that 4-hydroxybiphenyl is a niche chemical product. At present, there are not many domestic companies. Key production companies include Four companies, Xi’an Cisco Sai Industrial Co., Ltd., Wujiang New Sanlian Chemical Co., Ltd., Qingdao Frontline Bioengineering Co., Ltd., and Hebei Sinochem Fuheng Co., Ltd., occupy the majority of the market share in the domestic 4-hydroxybiphenyl industry. Therefore, China’s 4-hydroxybiphenyl industry is highly concentrated.