Gamma-butyllactone (GBL)

Gamma-butyllactone (GBL) downstream products are mainly:

In the downstream application of BDO industry chain products, gamma-butanolactone (GBL) is an important organic chemical raw materials and fine chemical intermediates, widely used in petrochemical, medicine, dyeing, pesticides and fine chemical and other fields, often used in the manufacture of α-pirolidone, NMP, polyethylene pirolidone, α-acetyl-gamma-butanolactone, etc.

(1) N-methylpyrrolidone (NMP)

It is obtained by the condensation of gamma-butyllactone and methylamine. As a highly selective solvent, the product is mainly used to extract acetylene, extract butadiene, isoprene, and extract aromatics from lubricating oil distillates to improve the quality of lubricating oil, especially as an environmentally friendly non-toxic solvent and electrolyte of lithium batteries. As a resin processing solvent for the manufacture of a variety of vinyl coatings; As the solvent of polymerization reaction, it is used to manufacture polyimide heat-resistant resin, polyamide, polyphenyl ether, etc. In addition, it can also synthesize fine chemicals such as medicine, pigment, fragrance and cleaning agent.

(2) Cyclopropylamine (CPA)

It is an important fatty amine containing three rings, mainly used in medicine, pesticides, fine chemical synthesis, etc., especially in medicine, the use of large, mainly synthesis of ciprofloxacin, anthrafloxacin, Sparfloxacin, ciprofluronic acid, etc.

γ-butylactone as raw material, synthesis steps are divided into five - step method and three - step method, the three - step method is more compact and advanced. Several large CPA companies abroad all use gamma-butyrolactone as raw material production. The research on CPA in China started relatively late, but now the domestic research and development is gradually mature and has the conditions for industrialization. There are mainly China Medical University, Tianjin Central Pharmaceutical Factory, Northeast Pharmaceutical General Factory, Zhejiang University, etc. The industrialization production was first realized by the open source chemical plant in Zhejiang University. In recent years, the third-generation quinolone antibacterial drugs showing strong antibacterial activity against staphylococcus and pseudomonas aeroginosa have been rapidly developed in foreign countries, among which ciprofloxacin (ciprofloxacin) and ciprofluronic acid are both produced with CPA as raw materials, and the demand for CPA is growing rapidly.

At present, our CPA production enterprises mainly include Zhejiang Shaxing Pharmaceutical and Chemical Company, Zhejiang Haixiang Pharmaceutical and Chemical Company, Xinchang Guobang Chemical Industry Company, Xi 'an Rehabilitation Pharmaceutical Factory, Hangzhou Xingyuan Science and Technology Industrial Company, Yangzhou Xingda Chemical Company, Huainan Third Pharmaceutical Factory and Jiangxi Province Pingxiang Mulberry Forest Chemical Factory.

(3) 2-pyrrolidone (α-pyrrolidone), n-vinylpyrrolidone (NVP) and polyethylpyrrolidone (PVP)

By γ-butyrolactone as raw material, ammoniation and 2-pyrrolidone, the product is nylon -4 monomer, plasticizer, polymer intermediate, can produce medical brain and aminoacid;

Using 2-pyrrolidone as raw material through the formation of potassium salt and dehydration, in acetylene ethylene reaction to obtain N-vinylpyrrolidone, the product is mainly used for the synthesis of polyethylpyrrolidone; Polyvinylpyrrolidone (PVP) for short, has excellent solubility, film formation, complexation, surface activity and chemical stability, is an important polymer product, usually according to the average molecular weight of different and different uses. Mainly used in medicine, food, daily chemical, coating, polymer polymerization, paper making, textile printing and dyeing, photographic materials, agriculture and other fields. The production and application of PVP started relatively late in our country, with few manufacturers mainly relying on imports. With the rapid demand of povidone iodine, food clarifying agent and moisturizing agent for daily cosmetics in China, the prospect of PVP development is extremely broad.

(4) 2-pyrrolidone 5-carboxylic acid

It is prepared from -carboxylic acid and gamma-butylactone by esterification, ammonification, cyclization, decompression heating and deamination. This product has three kinds of optically active isomers, mainly in the form of esters and salts, widely used in daily chemical, paper, leather, textile, medicine and food and other fields, there is no domestic production equipment, so the application is very limited.

(5) glutaric acid

From γ-butylactone as raw material, reaction with potassium cyanide, adding hydrochloric acid acidification to get glutaric acid monoamide, then heating hydrolysis to get glutaric acid. This product is mainly used as the initiator of synthetic resin, rubber and polymer and the curing agent of epoxy resin. At present, only a few domestic enterprises produce glutaric anhydride. With the rapid increase of the production of synthetic resin and epoxy resin, the domestic demand for glutaric anhydride increases rapidly.

(6) alpha-acetyl-gamma-butyrolactone (ABL)

This product is obtained by the multi-step reaction of GBL and methyl acetoacetate. It is an important fine chemical intermediate. Nantong Acetic Acid Chemical Co., LTD is the main manufacturer of this product, which is mainly used for the synthesis of vitamin B1, pesticide and medicine. Vitamin B1 is one of the three major vitamin varieties in the world at present, and our country is a major producer and exporter.

(7) gamma-hydroxybutyric acid

By gamma-butylactone hydrolysis, gamma-hydroxybutyrate is mainly used as a general anesthetic gamma-hydroxybutyrate sodium, often used in general anesthesia or induced anesthesia, as well as local anesthesia, auxiliary drugs of lumbar anesthesia, suitable for the elderly, children and brain, neurosurgery, trauma, burn patients anesthesia, is a very promising market anesthetic. In addition, it can be used as a special plasticizer for synthetic resin.

(8) succinic acid

Obtained by the oxidation of γ-butylactone, succinic acid is an important petrochemical raw material, used in the pharmaceutical industry for the production of sedatives, diuretics, antipyretic analgesics, contraception and cancer drugs; Succinate ester and salt, can be used for the synthesis of dyes, alkyd resins, vinyl resins, adhesives and rubber plasticizers, ion exchange resins, a variety of pesticides and fine chemical intermediates N, n-diethyl-n-propyl succinamide, etc.; Succinic acid and its sodium salt are used as food flavoring agent and flavoring agent.

(9) 2-bromo-chloro-butyrolactone

Gamma-butyrolactone can be obtained through different halogenated agents 2-bromo-butyl lactone, 2-bromo-butyl lactone is an important pesticide raw material, can be respectively and 3-chloro-2, 6-dimethylaniline, 2, 6-dimethylaniline synthesis fungicide antimycin, furamide and furamide, etc., these fungicides are new promising products. 2-chloro-butyrolactone has not been produced in China, and it is mainly used in the production of new drugs.

With the continuous development of the related industries, the demand for gamma-butylactone (GBL) in the above other areas will continue to grow, especially in medicine, pesticides, spices, artificial plasma and the preparation of vitamins and chlorophyll and other aspects, the prospect is promising, will become the new growth point of demand for GBL.

The production process of gamma-butyllactone (GBL)

At present, the industrialization of furfural process, butadiene chloride process, butadiene acetoxylation process, allyl alcohol process, Reppe process, esterification and hydrogenation of maleic anhydride, direct hydrogenation of maleic anhydride and so on. Among them, Reppe method, esterification and hydrogenation of maleic anhydride and direct hydrogenation of maleic anhydride are more competitive.

(1) 1, 4-butanediol dehydrogenation method (Reppe method)

This process was first developed by BASF Company in Germany in 1946 and achieved industrial production. The United States and European countries have adopted this method, and there are 10,000 tons of production scale. The optimum selection of catalyst and the adjustment of process parameters can lead to the difference of production capacity, conversion rate and selectivity.

The process includes three steps: condensation, hydrogenation and dehydration.

Condensation: Acetylene and concentration of 10% - 30% formaldehyde aqueous solution in copper acetylene catalyzed, 90 ~ 110℃, 0.5 ~ 2MPa under the condition of condensation into butynediol, 95% selectivity. In order to prevent the formation of propargylic aldehyde, excessive formaldehyde is required during the reaction.

Butanediol hydrogenation: BASF adopts high pressure fixed bed process to introduce 30% ~ 40% butanediol aqueous solution and hydrogen into a tower reactor equipped with Ni catalyst for reaction. Excessive circulating hydrogen gas is used to cool the heat released in the reaction. The selectivity of butanediol is 95%.

Butanediol dehydration: 1, 4-butanediol was dehydrogenated in gas or liquid phase at 200 ~ 250℃ under copper catalyst to produce γ-butanolactone, the yield was 90%.

In the Reppe process, in order to prevent acetylene explosion resulting in increased equipment investment, condensation reaction into the suspension method with stirring pressure circulation reaction, the catalyst suspended in the solution, reduce the possibility of explosion, to ensure safety, reduce investment, is a currently the most advanced Reppe method of production.

The main advantages of Reppe method are: the primary product only contains a small amount of tetrahydrofuran, butanol and unreacted raw material 1, 4-butanediol, the physical and chemical properties of each component are relatively different, the product is easy to separate, the synthetic γ-butanolactone quality is good, can meet the production of battery electrolyte and pharmaceutical raw materials on the quality of γ-butanolactone strict requirements. The economic competitiveness of the process mainly depends on the price and source of the raw material 1, 4-butanediol, which is suitable for the further production of various fine chemicals from gamma-butanolactone.

The preparation of γ-butanolactone with 1, 4-butanediol as raw material mostly uses the gas phase synthesis process, and the liquid phase synthesis process is less.

Ma Ning et Al in North China Institute of Water Resources and Electric Power investigated the catalytic activity in gas and liquid phases for γ-butanolactone preparation by Reppe method under atmospheric pressure. A CuO/ZnO/Al ₃ catalyst for 1, 4-butanol dehydrogenation was formulated in accordance with nitrates of metal ions such as Cu, Zn and Al. The optimum ratio of active components of the catalyst is Cu: Zn: AI= 2.25:2:1, and the calcination temperature is 500℃. The preparation process has the characteristics of wide raw materials and simple production process.

The optimum gas phase reaction conditions of the catalyst were as follows: the reaction temperature was 255℃, the liquid space velocity was 2.0h-1, the hydroalcohol ratio was 5.0, and the yield of γ-butylactone was more than 93%.

The optimum liquid phase reaction conditions of the catalyst were as follows: reaction temperature 195℃±5℃, liquid phase space velocity 0.29 ~ 0.31h-1, the catalyst dehydrogenation of 1, 4-butaneol to γ-butanolactone yield was not less than 91%. The catalyst has certain operability for the process conditions of 1, 4-butanediol dehydrogenation to γ-butanolactone, which is conducive to industrial application.

Shanghai Fudan University developed MAH normal pressure gas phase hydrogenation synthesis gamma-butylactone process, the process of raw material requirements are: MAH purity is greater than 98%, melting point 51~54℃, melt chroma (APHA), less than 100, ash less than 0.05%, heavy metals with lead less than 0.005%, iron less than 0.0005%, total sulfur less than 0.0001%, total halogen (calculated by chlorine) 0.001%. The gamma-butyrolactone produced by this method was colorless and transparent, with purity greater than 99.5% and water content less than 0.02%.

The process is characterized by catalytic reaction under atmospheric pressure, MAH one-way conversion rate is high, simple process, convenient operation, less investment, the production of gamma-butyrolactone products with high purity, good quality, worthy of promotion.

(2) maleic anhydride hydrogenation

The key of maleic anhydride hydrogenation is the choice of catalyst. The biggest advantage is that the raw material maleic anhydride has sufficient source and low price. The biggest disadvantage is that hydrogenation equipment requires high explosion-proof and hydrogen needs to be purified.

Maleic anhydride hydrogenation is divided into two processes: liquid phase hydrogenation and gas phase hydrogenation.

In 1971, Mitsubishi Chemical Corporation of Japan built the first kiloton industrial plant using maleic anhydride liquid hydrogenation. Japan's Hokkaido Organic Chemical plant adopts two-stage liquid hydrogenation process, Japan's tetrahydrofuran Company, Britain's ICI Company, etc., adopts one-step liquid hydrogenation process to build a kiloton production unit of 1, 4-butandiol, γ-butanolactone, tetrahydrofuran and flexibly adjust the proportion. The process includes catalytic hydrogenation and refining of crude products. Maleic anhydride, hydrogen and gamma-butylactone as solvent were passed into a single stage hydrogenation reactor containing Ni and other metals as solid catalysts. The reaction was carried out at 200℃ and 6 ~ 10MPa.

The gas phase hydrogenation process is developed by Standard OiI Company in the United States. The domestic institutes such as Beijing Academy of Stone Sciences, Nankai University and Fudan University have also carried out relatively perfect research and development on this process, and successfully realized industrialization.

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