The Synthesis Of Enal Glycol Acetal And The Application In Tobacco

Enals have special aroma of fruit, grass, roasted meats and so on, which giving tobacco special notes and become more and more popular in perfumers'good graces. however, they are unstable and evaporable, and will loss before smoked by consumer. So it is necessary to develop a new product or the precursor of enals to improve the stability, at the same time, with that kind of special notes. The acetals are stable in acidity and alkaline condition, and have tenderness aroma properties, which can pyrolysis to enal partly, so they are the ideal precursor of enals.Firstly, the acetalization of 2, 4-decadienal glycol acetal was studied. Effects of species of catalyst, species of water-carrying agent, the amount of antioxidant, the amount of catalyst, the amount of water-carrying agent and reaction time on reactions were investigated. Single element test and response surface methodology(RSM) were performed and the optimal reaction conditions are as follows: 0.06mol 2,4-decadienal,0.09mol glycol,0.5% of reactant (w/w)TBHQ as antioxidant,0.60% of reactant (w/w) vitamin C as catalyst,5.30mL hexane as water-carrying agent, reaction time as 3.54h,the yield could reach over 77.5%. The product was isolated by reduced pressure distillation, the residue of the vitamin C and TBHQ was determined by HPLC and GC and both of the residue content is lower than the detection limit, and the data of MS, IR were consistent with the structure of 2, 4-decadienal glycol acetal.The application of 2, 4-decadienal glycol acetal in tobacco was investigated. The results of flavoring sensory evaluation implied that 2, 4-decadienal glycol acetal can improve the aroma and harmony, lower the stimulation, improve the aftertaste of cigarette. We also determined its advice addition was 0.15～0.20‰.The result of pyrolysis implied the main pyrolysis products of 2, 4-decadienal glycol acetal is 2, 4-decadienal, and some small volatile molecule are also detected. The total content of 2,4-decadienal decreases as the temperature of pyrolysis, especially between 600 and 700℃. The mainstream smoke analysis showed the content of 2, 4-decadienal is 1.96% in the smoke, which means the 2, 4-decadienal glycol acetal has good performance as the precursor of 2, 4-decadienal. The mobility rate of 2, 4-decadienal in mainstream smoke is 10.58% The relation of yield and the carbon charge of carbonyl was acquired by comparing several kinds of the synthesis of enals glycol acetal, that is, the yield increases as the amount of the positive charge of the carbon charge of the carbonyl increases. The regression equations of the percent yield of acetal and the charge of the carbonyl carbon is: y = 445.49x -118.8, the correlation coefficient R2=0.9955The pyrolysis law of the acetal was acquired by calculation, the result implies the relation between the content of the acetals and the length of C-C adhering to dioxane is a negative correlation, that is, the shorter the length of C-Cathie higher the content of acetal.