Fine Utilization Of Acetylene

- Feb 05, 2019-

Abstract: Acetylene is an important organic chemical raw material. Its downstream products can be divided into two categories. One is acetylene special chemicals, such as acetylene aldehyde chemical (1, 4-butanediol series) ethynyl ether. , vinyl compounds, etc.; the other is petroleum ethylene, propylene and other downstream products, such as vinyl chloride, vinyl acetate and acrylic acid. In the case of high oil prices, acetylene chemicals will have a clear competitive advantage in certain areas. This article focuses on the use of acetylene-specific chemicals: 1, 4-butanediol series and vinyl compounds.

Key words: acetylene, 1,4-butanediol, vinyl compound, utilization

Acetylene, commonly known as wind coal, calcium carbide gas, contains a lively hydrazone bond, once known as the "mother of the organic synthesis industry", it can chemically react with many substances, derived thousands of substances. Despite the huge impact of ethylene raw materials in recent years, it produces 1,4-butanediol series (polybutylene terephthalate, γ-butyrolactone, tetrahydrofuran, etc.) and vinyl compounds (N-vinyl The technical route of using acetylene as a raw material such as lactam or vinyltrichlorosilane is still competitive . The preparation of acetylene is industrially based on the hydrolysis of calcium carbide (calcium carbide):

With the further rapid development of China's economy, especially the rising price of crude oil, the scale of PVC for calcium carbide process has been multiplied, and the demand for calcium carbide has also multiplied, resulting in a corresponding expansion in the capacity and production scale of calcium carbide furnaces. At the same time, new technologies and new methods were born in the calcium carbide industry, which promoted the continuous improvement and optimization of the Elkme calcium carbide furnace. Therefore, as a high-energy product, the production of calcium carbide will continue to increase. Calcium carbide is mainly used to produce acetylene . In the traditional field, acetylene is used as a welding gas for the production of products such as polyvinyl chloride and vinyl acetate. In recent years, the preparation of vinyl polymer monomers by the reppe method has been rapidly developed abroad, and BASF and ISP companies have built large-scale production facilities. Usually these compounds have higher added value than acetylene gas, polyvinyl chloride and vinyl acetate.

At present, there are two main types of acetylene refinement: one is a special chemical for acetylene, such as an alkyne compound (1,4-butanediol series), a reppe method (vinyl compound), and the like; The products are products such as propylene, petroleum and ethylene, such as polyvinyl chloride, trichloroethylene, tetrachloroethylene and acrylic acid. The production of such products has competition between the acetylene route and the petroleum route .

1 acetylene special chemicals

1.1 Alkyne method compound (1,4-butanediol series)

1,4-butanediol, abbreviated as BDO, is an important basic organic chemical and fine chemical raw material. It is widely used. Its derivatives are high-value fine chemical products, which are widely used as solvents, medicines, cosmetics, Plasticizers, curing agents, pesticides, herbicides, foam artificial leather, fiber and engineering plastics. At present, 1,4-butanediol is mainly used in the manufacture of tetrahydrofuran (THF), γ-butyrolactone (GBL), N-methylpyrrolidone (NMP) and polybutylene terephthalate (PBT). Engineering plastics, etc.

Since the 1970s, the rapid development of the 1,4-butanediol has been promoted due to the rapid development of the polyurethane industry and polybutylene terephthalate (PBT) engineering plastics. In recent years, PBT engineering plastics and PBT fibers have been widely used in the automotive, machinery, electronics and electrical industries due to their ease of processing, excellent electrical properties, mechanical and thermal resistance. PBT fiber has excellent elasticity (better than nylon), good dyeability and water absorption, and full hand feeling. It is mainly used in high-end sportswear, women's underwear and tights, and has a large potential market. 1,4-butanediol-derived tetrahydrofuran (THF), which is used as a solvent and chemical raw material. Promising is polytetrahydrofuran (PTMEG). PTMEG is a raw material for high performance polyurethane resin (PU) and high performance elastic fiber spandex (SPANDEX).Between 2005 and 2010, the domestic demand for 1,4-butanediol increased at an average annual rate of 14.2%, and the demand reached 268,000 tons. Although the contradiction between supply and demand in the domestic market will be eased, there is still a gap. In 2010, the domestic PBT production capacity will reach 150,000 tons/year, and the output will be about 120,000 tons. The corresponding demand for 1,4-butanediol will reach 60,000 tons, which is the most demand for 1,4-butanediol. Fast field. It is estimated that the domestic demand for 1,4-butanediol will reach 375,000 tons by 2015, and the average annual demand growth rate will be 6.9% between 2010 and 2015. The faster growth in demand is still in the PBT and tetrahydrofuran sectors.

Preparation method of 1,4-butanediol (BDO):

Note: Formaldehyde can be produced by purification and catalytic hydrogenation of calcium carbide tail gas; The intermediate 1,4-butynediol (abbreviated as butynediol, BD) is an important organic chemical raw material. It is an intermediate of fine chemicals such as medicines and perfumes. It is used to produce enol and halogenated enol. Pyrrolidone chemicals

1.2 vinyl compound (reppe method compound)

Vinyl compounds are functional monomers that are widely used. The currently used method for vinyl functional monomers is prepared by acetylene pressure reaction. The reaction formula is:

X = N, O, Si, C, and the like. Rn = alkyl, phenyl, carbonyl, halogen, and the like.

There are many kinds of vinyl functional monomers, such as N-vinyl caprolactam (NVCL), which is an important organic intermediate due to the presence of active vinyl groups in its molecule. Its homopolymer, vinyltrichlorosilane, etc. It is a commonly used functional monomer. Or graft copolymerization with other monomers such as glucose or dextran to obtain a water-soluble temperature-sensitive polymer material, and a temperature-sensitive polymer having such properties can be used for controlling drug release or controlling chemical reaction ; Vinyl silane coupling agents are used in a wide range of applications, such as surface treatment agents for glass fibers, fillers for inorganic fillers, sealants, tackifiers for adhesives and coatings, crosslinkers for cross-linked polyethylene, and difficult-to-bond materials. Adhesion promoter, etc

2 Products that compete with the oil route

China's PVC production capacity exceeds 200 × 104 t / a, of which calcium carbide acetylene raw materials account for about 70%, petroleum ethylene raw materials account for 30%; China's vinyl acetate production capacity of 50 × 104 t / a, domestic acetylene law dominates, except The Beijing Organic Chemical Plant changed from the calcium carbide method to the ethylene method for environmental reasons, and the rest were mostly acetylene methods [14]. In the domestic “Eighth Five-Year Plan” period, a pilot test of 300×104 t/a acetylene carboxylate synthetic acrylic acid was carried out. Whether the process route has competition is the price of acetylene and propylene.

3 Conclusion

With the further rapid development of the economy, especially the rising price of crude oil, it has created a good profit margin for the downstream products of acetylene. Acetylene was once known as the mother of organic. In the past, the phenomenon of "heavy olefins and light alkyne" will change with the transformation of resources. At the same time, the construction of ethylene needs to be under the conditions of petroleum resources and huge capital. However, in some areas of China, such as Gansu, there is no condition for ethylene. These areas are rich in calcium carbide resources. Therefore, acetylene chemical industry should be actively developed in these areas. The research and production of acetylene special chemicals and derivatives are still in the initial stage, and the development of acetylene chemical industry will have realistic and far-reaching significance.