Butanediol HOCH2CH2CH2CH2OH is mainly 1,4-butanediol in the industry. It is a colorless liquid with a boiling point of 228 ° C, a freezing point of <-50 ° C, and is soluble in water. It is mainly made from acetylene and formaldehyde. It is used as a chain extender for the production of polybutylene terephthalate and polyurethane, and as an important raw material for tetrahydrofuran, γ-butyrolactone and pharmaceutical and organic synthesis. Since polybutylene terephthalate is an excellent polyester, the demand for engineering plastics is growing rapidly.
Trade Name: 1,4-Butanediol ( BDO)
Molecular formula: C4H10O2
English abbreviations: BDO
Folding in cosmetics
Butanediol is very common in cosmetics. The English name that often appears is: Butylene Glycol, also known as 1,3-dihydroxybutane, which is a kind of polyol. It is often used as a moisturizer and solvent in cosmetics. In terms of moisturizing, since butanediol is a small molecule moisturizing ingredient, the proportion of water grabbing is small, and there is also a certain antibacterial effect. The safety of butanediol is worthy of recognition. The test showed that when applied intermittently to the human body, it was applied once every other day for 16 days. No irritating inflammation was found among all 200 people who participated in the test. . Regarding the irritation to the mucous membrane of the eye, it has been tested in white mice, and the results obtained are still highly safe. It is said that it has been used in toothpaste for four weeks of oral tests. As a result, it is also non-irritating to the oral mucosa and is a highly safe ingredient.
Folding production method
Before the Second World War, Germany had used the Repe method to synthesize butanediol from acetylene and formaldehyde. This method solves the danger of acetylene operating under high pressure and is still the main production method of butanediol. In the 1960s, Mitsubishi Oil Chemical Co., Ltd. developed a process for the preparation of butanediol by catalytic hydrogenation of maleic anhydride. In the 1970s, the company developed a new process for the butadiene acetoxylation process. In 1971, Japan’s Toyo Soda Industrial Co., Ltd. established a production facility for butadiene chlorination. In addition, the United States and Japan have successively studied various synthetic methods using propylene or ethylene as raw materials.
Repefa This method was developed by the German W.J. Repe, and the reaction was carried out in two steps.
1 An aqueous solution of acetylene and formaldehyde is reacted in the presence of a silica-supported copper-containing acetylene catalyst to form 2-butyne-1,4-diol (abbreviated as 1,4-butynediol): 2HCHO+HCCH- →HOCH2CCCH2OH
The reaction is carried out in a fixed bed reactor with a partial pressure of acetylene of 0.5 MPa and a reaction temperature of 90 to 100 ° C. The selectivity of 1,4-butynediol is up to 80% in terms of acetylene and greater than 90% in terms of formaldehyde.
2 Hydrogenation of 1,4-butynediol to 1,4-butanediol: HOCH2C呏CCH2OH+2H2─→HOCH2CH2CH2CH2OH Hydrogenation can be carried out at 70~140°C, 30MPa, with silicon-containing carrier (see silica gel carrier) The nickel-copper-manganese was used as a catalyst, and the yield of 1,4-butanediol was 95%.
The US General Aniline and Film Company has made improvements to this law. In the first step, the catalyst was changed to copper acetylide supported on magnesium silicate, and ruthenium was contained to inhibit the polymerization of acetylene. The catalyst is safe to use and is not easily deactivated. The reaction conditions are a temperature of 95 ° C and an acetylene partial pressure of 0.2 MPa. The tank reactor with stirring is used, and the solid catalyst is suspended in the liquid reaction medium. The second step of hydrogenation is carried out in two steps: first, low-pressure liquid phase hydrogenation, the catalyst is framework nickel, the reaction temperature is 50-60 ° C, the pressure is 1.4-2.1 MPa, and the tank reactor with stirring is used, and then in a fixed bed. High pressure liquid phase hydrogenation.
The production process of Repefa is not too complicated and the cost is low. At present, the production capacity of this method is close to 90% of the total capacity of various methods. The key to the development of this method in the future is the supply and price of acetylene raw materials.
The maleic anhydride hydrogenation reaction is carried out in two steps to co-produce tetrahydrofuran. 1 liquid phase catalytic hydrogenation of maleic anhydride to γ-butyrolactone and tetrahydrofuran, the catalyst is nickel-ruthenium, the reaction temperature is 240-280 ° C, the pressure is 5.8~11.5 MPa, and the conversion rate of maleic anhydride is 100%. The selectivity to γ-butyrolactone and tetrahydrofuran is 90%. The molar ratio of γ-butyrolactone to tetrahydrofuran can be adjusted in the range of 10:1 to 1:3 using different reaction conditions. 2γ-butyrolactone is further hydrogenated to obtain 1,4-butanediol, and a copper chromium catalyst using potassium oxide as a promoter has a conversion rate of 85% to 90% and a selectivity of 99% at 200 ° C and 10 MPa. the above.
This method has high raw material prices, but has few reaction steps, low investment, and adjustable co-products. Therefore, many countries are still stepping up research and development. The butadiene acetoxylation process is carried out in three steps to co-produce tetrahydrofuran.
21,4-Diacetoxy-2-butene is subjected to liquid phase hydrogenation in the presence of a palladium catalyst at 60 ° C and 5 MPa to obtain 1,4-diacetoxybutane in a yield of 98%.
The 31,4-diacetoxybutane is hydrolyzed by an ion exchange resin catalyzed (see solid acid catalyst) to produce the product 1,4-butanediol.
1,4-Dichlorobutene Process In the production of chloroprene from butadiene, 1,4-dichlorobutene is an intermediate product. The method developed by Toyo Soda Industrial Co., Ltd. is to hydrolyze 1,4-dichlorobutene with an excess of sodium formate at about 110 ° C to form 2-butene-1,4-diol with a conversion of nearly 100% and a selectivity of more than 90. %. After hydrolysis, the free formic acid was neutralized with sodium hydroxide. The 2-butene-1,4-diol is then hydrogenated in the presence of 100 ° C, 27 MPa and a nickel-aluminum catalyst to give 1,4-butanediol. This method has a high cost of public works and a high production cost.
Allyl alcohol can be prepared from propylene, so this method can also be considered as a method starting from propylene. From propylene, allyl acetate or acrolein can also be used to produce 1,4-butanediol, but these methods are still only in the development stage.