1, 4-butanediol (BDO), as an important organic chemical product, is the main raw material of fine chemical products with high added value and synthetic leather. In addition to the production of polybutylene terephthalate (PBT), polyadipic acid/butylene terephthalate (PBAT), polybutylene terephthalate (PBS), γ-butyrolactone (GBL), polyurethane (PU), tetrahydrofuran (THF), polytetrahydrofuran (PTMEG), N-methylpyrrolidone (NMP), polyethylene pyrrolidone (PVP), etc., in addition to the synthesis of vitamin B6, pesticides, herbicides and solvents, humidifiers, plasticizers, pharmaceutical intermediates, chain growth agents and adhesives.
In this paper, three kinds of coal-based BDO-derived fine chemicals, namely 1, 4-butenediol, 3-butene-1-ol and propargyl alcohol, are introduced.
1, 1, 4-butenediol
1, 4-butenediol (BED), widely used in pesticides, pharmaceutical intermediates, chemicals, batteries, paper, leather and other fields, can be used to synthesize the main intermediate of vitamin B6 n-propyl dioxoheptadiene ring. The production process of BED is 1, 4-butynediol (BYD), which is further distilled by semi-hydrogenation reaction. Its raw materials are intermediate products produced by BDO, and by-products BDO and n-butanol produced by BED can be reused for BDO production. Therefore, the BDO device extension coproduction BED has a cost advantage.
The downstream use of BED mainly produces vitamin B6 and broad-spectrum insecticide endosulfan, and the BED usage is 20700t/a and 3160t /a, respectively. In addition, BED can be used to produce 1, 4-dicyano-2-butene, and further hydrogenation can produce hexamethylene diamine, and hexamethylene diamine and adiponic acid can produce nylon 66 salt under certain reaction conditions, and the technical monopoly of adipdinitrile can be broken in the production of nylon 66 (adipdinitrile hydrogenation can produce hexamethylene diamine).
2, 3-butene-1-ol
3-butene-1-ol (BTO), as an important pharmaceutical intermediate, is widely used in plastic lenses, petroleum processing and other fine chemical fields, especially in the pharmaceutical field for the synthesis of heterocyclic derivatives of new drugs, such as anti-tumor drugs, anti-AIDS drugs and other important intermediates. In recent years, with the rapid increase in the use of anti-tumor drugs such as pemetrexed disodium, the demand for BTO is also increasing.
The production process of BTO is BDO gas phase dewatering method, which uses metal oxide as catalyst to catalyze BDO to select dehydration to synthesize BTO under gas phase conditions. It has the characteristics of mild reaction conditions, environmental friendliness, and easy separation of products, etc., which is a BTO synthesis route with competitive advantages. Although China's current BTO synthesis technology research results are rich, but in the process of industrialization there are still many technical defects, such as low catalyst yield and selectivity, the product is not easy to separate resulting in high energy consumption, but the construction of a co-production unit with BDO production unit can make full use of raw material BDO, with cost advantages.
3. Propargyl alcohol
Proparyl alcohol (PA) is an important organic synthesis intermediate, mainly used in the production of acrylyl alcohol, acrolein, vitamin A in the pharmaceutical industry, the pesticide industry for the synthesis of clarite pesticides, bright agent in the electroplating industry, rust remover in the iron and steel industry, efficient acidizing corrosion inhibitor in the oil mining industry.
The traditional production process is high pressure acetylene method, the reaction pressure is 2.0MPa, and the production of 6-8 reaction reactors is cascade. The operation risk of this process is larger, the process flow is complex, and the requirements for equipment and operators are higher. In the BDO production process, formaldehyde reacts with acetylene to produce 1, 4-butynediol (BYD), while producing about 0.5% ~1.0% intermediate product PA. PA products can be obtained by adding a rectification tower in the BYD rectification section. This process requires no new reaction device, and the process is simple, less dangerous, and has cost advantages.
Industrial chain construction and development suggestions
Since 2021, BDO devices have been large-scale and increasingly mature, with a typical BDO device production capacity of 100,000 to 150,000 t/ set. In the case of continuous expansion of BDO production capacity and impending overcapacity, BDO enterprises achieve product enrichment and cost transfer between upstream and downstream by building upstream and downstream industrial chains and derivative fine chemicals. It will become the main way for BDO enterprises to survive and develop.
In addition, BED, BTO and PA scale are thousand tons, the device covers a small area, small investment, can be used as an auxiliary device supporting construction, to further enrich the product structure, enhance the ability to resist market risks.
