| Tetrabromobisphenol-A is an excellent flame retardant, thus the reaserch on the synthesis of tetrabromobisphenol-A is of great significance.Solvent is one of the most important factors may impacted the yield, melting-points, the appearance of the product and the tecnics, as a result, the reaserch on solvets is always the emphesis of reseach. In this paper, tetrabromobisphenol-A was synthesized from bisphenol-A, bromine, hydrogen peroxide by in-situ bromination-oxidation, with fatty alcohols, chlorobenzene, nitrobenzene, hexamethylene, acetic acid, chlorobenzene-alchols, hexamethylene-alchols as the organic solvents, at the same time the effects of the solvents on the reaction were reasearched.In this paper, we tried to synthesize tetrabromobisphenol-A with 1-octanol as organic solvent. The optimal conditions for the reaction were as follows: n(bisphenol-A): n(bromine): n(hydrogen peroxide) was 1:2.05:2.1, the reaction temperature was at 25℃, the aging condition was at 80℃for 60min, V(1-octanol): V(water) was 4:1, and the total volume of solvent was 110ml when the mount of bisphenol-A was 28.5g. The yield of tetrabromobisphenol A based on bisphenol A was more than 98.4% and the melting point was between 178.0℃to 181.3℃under the optimal condition while using recycled solvent.In this paper, other alcohols were also used as organic solvents to synthesize tetrabromobisphenol-A, the optimal moleculercular ratio was studied especially and the quality of the products reached the applied standard.In this paper, the acetic acid was used as the organic solvent to synthesize tetrabromo- bisphenol-A. The optimal conditions for the reaction were as follows: n(bisphenol-A): n(bromine): n(hydrogen peroxide) was 1:2.06:2.10, adding-time of bromine and hydrogen peroxide were 35min respectively, V(actic acid): V(water) = 9:1 and the total volume of solvent was 3.86mL/g bisphenol-A. The yield of tetrabromobisphenol A based on bisphenol A was more than 96.0%, the purity was above 99.4% and the melting point was between 180.1℃to 182.5℃.In this paper, chlorobenzene was used as the organic solvent for the sythesis of the tetrabromobisphenol-A, and the optimal conditions for the reaction were as follows: n(bisphenol-A): n(bromine): n(hydrogen peroxide) was 1:2.15:2.2, the reaction temperature was at 25℃, adding-time of bromine and hydrogen peroxide were 30min respectively, the aging condition was at 94℃for 60min, and the total volume of solvent was 2.46～3.16mL/g bisphenol-A. The yield of tetrabromobisphenol A based on bisphenol A was more than 90.0%, the purity was above 99.4%.In this paper, chlorobenzene-alcohols were used as the organic solvents to synthesize tetrabromobisphenol-A, and the optimal conditions were as follow: n(bisphenol-A): n(bromine): n(hydrogen peroxide) was 1:2.15:2.2, the reaction temperature was at 20℃, adding-time of bromine and hydrogen peroxide was 30min, respectively, the aging condition was at 80℃for 60min, and the total volume of solvent was 3.5mL/g bisphenol-A, V(chlorobenzene): V(isooctanol) = 4:1. The yield of tetrabromobisphenol A based on bisphenol A was more than 99.5%, and the melting point was 179.7℃～182.4℃. This process, by contrast chlorobenzene, avoided washing by water and alkali, so saved time and water, and enhanced the produce efficiency.In this paper, cyclohexane and cyclohexane-alcohols were used as the organic solvents to synthesize tetrabromobisphenol-A, the effects of the proportion of the materials on the reaction were discussed, and experiments of recycling solvent were carried on. The results were as follow:With cyclohexane-1-octanol as the solvents, the optimal condition were as follow: n(bisphenol-A): n(bromine): n(hydrogen peroxide) was 1:2.1:2.15, the total volume of solvent was 3.5mL/g bisphenol-A, V(cyclohexane): V(isooctanol) = 4:1, the reaction temperature was at 20℃, adding-time of bromine and hydrogen peroxide were 30min respectively, the aging condition was at 80℃for 60min. The yield of tetrabromobisphenol A when using recycled solvent based on bisphenol A was more than 93.0%, the purity was above 99.3%, and the melting point was 179.0℃～182.8℃.With cyclohexane-isooctanol as the solvents, the optimal condition were as follow: n(bisphenol-A): n(bromine): n(hydrogen peroxide) was 1:2.08:2.1, the total volume of solvent was 3.5mL/g bisphenol-A, V(cyclohexane): V(isooctanol) = 4:1, the reaction temperature was at 20℃, adding-time of bromine and hydrogen peroxide was 30min respectively, the aging condition was at 80℃for 60min. The yield of tetrabromobisphenol A when using recycled solvent based on bisphenol A was more than 91.0%, the purity was above 98.9%, and the melting point was 178.0℃～182.5℃.In addition, tetrabromobisphenol-A was synthesize by continuous process, and the optimal technics conditions were as follow: n(bisphenol-A): n(bromine): n(hydrogen peroxide) was 1:2.08:2.1, the reaction temperature was at 60℃, the reaction time was 40 min, the aging time was 60min, the aging temperature was 94℃. The yield of the product was above 95%, the melting point was 178.0℃～182.0℃under this optimal condition. |
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