Synthesis Of Octopirox Intermediate 4-Methyl-6-(2,4,4-trimetylpentyl)-2-Pyrone And Measurement Of Correlated Heat Capacities

Octopirox is a kind of powerful anti-dandruff agent with advantages on removing dandruff over other ones.It has good cooperation with other components of shampoo.And it is safe to people with no stimulation,no toxic.So,Octopirox has great application value.In this study,a synthesis route with higher yield and practicable operation has been chosen based on synthesis method of similar compounds for 4-methyl-6-(2,4,4-trimethylpentyl)-2-pyrone,which is an important intermediate of Octopirox.It is prepared with 3,5,5-trimethyl hexanoyl chloride and methyl 3-methyl-2-butenoate by acyl chlorination,F-C acylation, hydrolysis and lactonization,reaction,and the total yield is 52%.The effects of temperature, amount of catalysts and the ratio of substrate in each step have been investigated,and the suitable conditions for the process have been obtained.And also,heat capactites for correlated compounds of synthesis of Octopirox have been studies in this paper.Heat capacities of binary mixtures of acetic acid with acetic anhydride and methenamine were measured by cooling method with a simple calorimeter from 308.15 K to 333.15 K at atmospheric pressure with different compositions.The values of C_p is correlated with temperatures and molar fraction,and the RMSD between the experimental and calculated values is 0.46%and 1.47%separately.The excess molar heat capacities C_p~E of the binary mixture of acetic acid with acetic anhydride were calculated from the experimental data,and were fitted to the Redlich-Kister equation,and the AAD between experimental and calculated values is 5.68%.