Preparation background and overview of 2,3-dichlorotetrahydrofuran
2,3-Dichlorotetrahydrofuran is similar to tetrahydrofuran. It is a widely used organic solvent. It can dissolve almost all polymers except polyethylene, polypropylene and fluororesin. It is especially suitable for polyethylene, Polyvinylidene resin and styrene-butadiene rubber. In organic synthesis, 2,3-dichlorotetrahydrofuran is often used as a solvent. In addition, the demand for 2,3-dichlorotetrahydrofuran as a binder is also large. 2,3-Dichlorotetrahydrofuran is also used in the precision tape industry. Tetramethylene ether glycol, a polymer of 2,3-dichlorotetrahydrofuran, is the raw material for the synthesis of polychloronitrogen elastic fibers and polyurethane elastomers.
Preparation of 2,3-dichlorotetrahydrofuran
1. Preparation of hydrogenation catalyst
Put 52.2g Cu(NO3)2.3H2O (product of Beijing Chemical Plant, chemically pure), 23.2g 50% Mn(NO3)2. aqueous solution (product of Beijing Chemical Plant, chemically pure), 8.1g Al(NO3)3.9H2O (Beijing Chemical plant product, chemically pure) was dissolved in 600 ml of deionized water, stirred at 50°C tetrahydrofuranthiol; 1°C, and 12wt% ammonia water (Beijing chemical plant product, chemically pure) was added dropwise until the pH of the solution was 5.5±0.5, aged 1 hour, then filter, wash with water once, collect the precipitate, dry at 200°C for 2 hours, and calcine at 500°C for 2 hours to obtain catalytic A: CuMn0.15Al0.1O1.3.
2. Preparation of eta-Al2 difluorophenylboronic acid O3 catalyst
Put 50g of mixed hydrous alumina containing diaspore and diaspore (70% of which is diaspore) in a muffle furnace and roast it at ℃ for 4 hours to obtain eta-Al2O3 catalyst D, with a specific surface area 215m2/g, pore volume 0.57ml/g.
3. Preparation of tetrahydrofuran
Using dimethyl maleate as the raw material, Catalyst A as the first stage catalyst, the hydrogenation reaction conditions are 189±1°C, 5.8±0.2Mpa, H2/ester 269:1 (mol), the hourly space velocity of the raw material liquid is 1.8 React under conditions of h-1, catalyst D is the second stage catalyst, reaction conditions are 300±2°C, 0.1Mpa, liquid hourly space velocity 90h-1, and the obtained product is tetrahydrofuran.
4.Preparation of 2,3-dichlorotetrahydrofuran
2,3-Dichlorotetrahydrofuran was synthesized using sulfuryl chloride and tetrahydrofuran as raw materials and carbon tetrachloride as solvent. The optimized reaction conditions are: 1.4 mol of tetrahydrofuran, 1 mol of sulfuryl chloride, and 50 ml of carbon tetrachloride. The reaction is carried out at 65-75°C for 1 hour. The yield reaches 79.3℅. The purity of the product is 95.6 after gas chromatography analysis. ℅, and confirmed the chemical structure of the product through IR, HNMR and GC-MS.
