Background and overview of the preparation method of tetrahydrofuran titanium chloride
Since Inoue first realized the copolymerization of carbon dioxide and propylene oxide in 1969, alkyl zinc/active hydrogen synthesis fluorphlogopite catalytic system, zinc carboxylate system, double metal cyanide catalyst, rare earth three-way catalyst, and metal porphyrin have appeared successively. A series of catalytic systems such as pholine catalysts, phenol zinc salt catalytic systems and diimine zinc catalysts. The research and development of these catalytic systems have a great role in promoting the synthesis of fully biodegradable aliphatic polycarbonates. Some systems have already It is used in industrial production, but the above system still has the problems of low catalytic activity and long reaction time. The tetradentate Schiff base cobalt complex (Selen) CoX catalytic system that began to appear in 2003 has developed rapidly, and two-component catalytic systems and active collectives composed of (Selen)CoX complexes and quaternary ammonium salts or quaternary phosphorus salts have appeared successively. A single-component bifunctional catalytic system integrating point and sterically hindered organic base groups. The activity of these two types of catalysts reaches 106 grams of polymer/mol of catalyst. However, cobalt, as a toxic metal, is strictly restricted in various international standards, making it difficult to popularize polycarbonate materials produced by cobalt-based catalytic systems for use in food and medical packaging fields. Therefore, this type of material has higher The active tetradentate Schiff base cobalt complex catalyst has been unable to be applied in actual industrial production. Research has provided a titanium-based catalyst such as tetrahydrofuran titanium chloride. The titanium-based catalyst provided is an efficient catalyst that can efficiently catalyze the copolymerization of carbon dioxide and epoxy compounds, and the resulting polyester is non-toxic.
Preparation method of tetrahydrofuran titanium chloride
Tetrahydrofuran titanium chloride is prepared as follows: Add granular titanium (~100 mesh, 99.9 purity, 8.3g), titanium tetrachloride ( 98.6g) and toluene (800g). THF (432g) was added under ice cooling while maintaining the tank temperature at 10-20°C. The reaction mixture was heated to reflux (90-100°C) for 6 hours. The reaction mixture was then cooled to room temperature and filtered. The solid tetrahydrofuran titanium chloride product was washed with deoxyhexane (200 mL) and dried in vacuo, yield = 240 g; 94%, based on total titanium charge (TiCl4 and granular titanium).
