2-甲基-2-羟基-1-苯基-1-戊酮的合成

Synthesis of 2-Methyl-2-Hydroxy-1-Phenyl-1-Pentanone

首先以2-甲基戊酸、氯化亚砜合成了2-甲基戊酰氯;其次,以无水三氯化铝为催化剂,苯与2-甲基戊酰氯反应合成了2-甲基-1-苯基-1-戊酮;最后在氢氧化钠水溶液中,以四氯化碳为氯化试剂,四丁基溴化铵作相转移催化剂,2-甲基-1-苯基-1-戊酮直接氯代和水解制得2-甲基-2-羟基-1-苯基-1-戊酮。结果表明,当2-甲基戊酸与二氯亚砜的物质的量比为1.0∶1.5、二氯亚砜的滴加温度为40℃、滴加时间1.5 h、反应时间2.5 h、无水三氯化铝的质量18.5 g、苯的用量45 mL和2-甲基戊酰氯的滴加时间0.5 h时,2-甲基-1-苯基-1-戊酮的收率为92.7%;当2-甲基-1-苯基-1-戊酮与四氯化碳的物质的量比为1.0∶1.8、四丁基溴化铵用量为6 g、质量分数为20%的NaOH溶液、反应时间为5 h时,2-甲基-2-羟基-1-苯基-1-戊酮的收率为91.2%。通过元素分析、红外光谱分析、质谱分析对产品进行了结构表征。

First, 2-methyl isocaproyl chloride was prepared by 2-methylvaleric acid and thionyl chloride. Second, 2-methyl -1- phenyl-1- pentanone was synthesized with benzene and isocaproyl chloride in the presence of anhydrous aluminum chloride as a catalyst. Then, 2- methyl- 2- hydroxy- 1- phenyl- 1- pentanone was prepared by chlorination and hydrolysis with 2-methyl-1- phenyl-1-pentanone in the presence of NaOH and CCl4 as chlorinating agent and tetrabutyl ammonium bromide as the phase transfer catalyst. The result shows：when n （2-methylvaleric acid）/n （thionyl chloride） is 1.0 ： 1.5. dropwise temperture and time of thionyl chloride is 40 ~C and 1.5 h respectively, reaction time is 2.5 h, anhydrous aluminum chloride is 18.5 g , benzene is 45 mL, dropwise time of isocaproyl chloride is 0.5 h, the yield of 2-methyl-1- phenyl 1 pentanone is 92.7% when n（2-methyl-1- phenyl-1-pentanone）/n（CC14 ） is 1.0 ： 1.8, tetrabutyl ammonium bromide is 6 g , mass fraction of sodium hydroxide is 20% and reaction time is 5 h, the yield of 2-methyl-2-hydroxy-l-phenyl-1 -pentanone can be up to 91%. The structure of the product was characterized by elemental analysis, IR and MS.