The Reactivity Of Dibromomethane

With the development of the society and the depleting of coal and petroleum, C1hydrocarbon resources are attracting much attention. In C1chemistry, the synthesis of various chemicals via halogenatingreaction of methane has always been a hot research field to scientists over the world, while the preparation of halomethane with high selectivity and the development of downstream products are very difficult. A lot of hard works will be needed.Our group are experienced in synthesis of dibromomethane with high selectivity via bromination reaction of methane by photochemical method, and we obtained Methanal, Dimethoxymethane(DMM), Dimethyl-carbonate(DMC), Carbamide.etc. Now, we use dibromomethane as the raw material to get some high value-added downstream products.1. Three trizine azacyanine were prepared firstly by the reaction between dibromomethane and2-aminopyridine derivatives. The synthsis technique is simple. The highest productivity of azacyanine (90.1%) was obtained over0.01mol2-aminopyridine and15mL dibromomethane at120℃for3h. We also determined the crystal structure of6H-Dipyri[1,2-a:2',1'-d][1,3,5]triazin-5-ium monohydrate which belongs to monoclinic system with space group P21, and the crystal parameters were a=5.495±2A, b=11.939±4A, c=17.717±6A, α=90°, β=95.370±6°, γ=90°. UV-VIS indicated that these azacyanine compounds have strong absorption in UV and visible light region, and it is suggested that these azacyanine compounds can be used as ultraviolet absorbers.2. Dibromo-polyresorcinol dimethyl ether (DPDE) was produced by the reaction between dibromomethane and resorcinol under the alkalinity environment. In optimal conditions (the molar ratio of resorcinol and sodium hydroxide and dibromomethane is1:4:2, the reaction temperature is160℃and the reaction time is6h), we could obtain the highest resorcinol conversion(74.5%) and the MPPO selectivity(80.0%) and the MPPO yield(60.0%). The synthetic process which is reacted in self-pressure autoclave is simple and the by-products are sodium bromide and water.3. The synthesis of liquid polysulfide rubber was investigated. We used dibromomethane,1,3-propanediol, sodium ethoxide, sodium disulfide to get new-type thiokol. This innovative technique may avoid ethylene oxide which is flammable, explosive and carcinogenic and corrosive concentrated hydrochloric acid and poisonous formaldehyde. FT-IR and GPC indicated that we managed to synthesise the thiokol which the average molecular weight is1782g/mol.