Synthesis And Formulation Of Terpenoid Repellent R2

Hydroxycitronellal propylene glycol1,2-acetal(R2) was synthesized from the reaction of hydroxycitronellal and1,2-propylene glycol with the existence of sulfamic acid and toluene which were catalyst and solvent respectively. The effects of molar ratio of hydroxycitronellal to1,2-propylene glycol, reaction temperature and reaction time on the GC purity of R2were investigated. The reaction conditions were optimized using response surface methodology. As a result, the optimal synthesis conditions of R2were obtained as follows:115g hydroxycitronellal purity is93%, molar ratio of hydroxycitronellal to1,2-propylene glycol was1:3.523, molar ratio of hydroxycitronellal to toluene was1:2-1:2.5, reaction temperarure was38.5℃, reaction time was4.37h. Under this condition the GC purity of the R2was91.88%, such a condition we got gave a optimized synthetic technology to the industrialization of R2. The structure of R2was identified by IR, MS,1H NMR,13C NMR.Orthogonal experiment was designed to optimize formula of R2spray as follows (mass percentage):R2was10%, solubilizer was20%, synergist was1%, sodium hyaluronate was0.05%, preservative was0.4%, flavor was0.5%, distilled water was63%. Spray was obtained by mixing R2, distilled water and other constituents with solubilizer adequately obeyed water-added law.According to the industry standard QB/T2660-2004, the physical and chemical characters (R2externality, pH value and concentration of R2) of R2spray were tested under the conditions of high temperature, low temperature and long-time storage, respectively. The results showed that the externality of R2spray was transparent, the pH value was6.5to7.5without obvious change, and the concentration of R2didn’t decline. The effective protection time of R2spray with the concentration of10%against Aedes albopictus、Culex pipiens quinquefasciatus、Culex pipiens was4.0h,4.5h and4.0h, respectively, which was agreement with B-level of GB.In addition, the optimized formula of R2gel was obtained after orthogonal and single factor experiment as follows (mass percentage):R2was12.5%, Carbomer940was1%,1,2-propylene glycol was5%, glycerin was5%, sodium hyaluronate was0.1%, triethanolamine was1%, preservative was0.2%and deionized water was75.2%.Subsequently, the physical and chemical characters of R2gel were tested, according to the industry standard QB/T1857-2004. The results were shown as follows:the R2gel contained no accumulation, pH value was confined into the range of6.5-8.0without obvious change, and the biological constituents didn’t make obivious change under the conditions of high temperature, low temperature and long-time storage. The effective protection time of R2gel with the concentration of10%against Aedes albopictus、Culex pipiens quinquefasciatus、Culex pipiens was4.0h,5.0h and4.0h, respectively, which was agreement with B-level of GB.