Physicochemical Properties And Refined Processing Technology Of Lacquer Wax

Toxicodendron vernicifluum (Stokes) is one of Chinese traditional economic forest. The resources of lacquer trees and their seeds are very rich in China, among these trees more than 30 species contained 1 million trees can produce more than 1.5 million tons of lacquer berries, which means 0.6 million lacquer lipids. Lacquer lipids contain lacquer wax and lacquer oil, which extract from the pulp and seed kernels of the lacquer berries. However, these rich resources currently have not been fully used. On the one hand is that the traditional idea of processing raw lacquer does not change, on the other hand, backward processing technology, high cost and small scale of deep processing limited the utilization of lacquer lipids. In order to promote the fine use of lacquer lipids, physicochemical properties, extraction process, decoloration process and hydrogenation were studied.Studies are necessary as physicochemical properties of lacquer lipids are different between different kinds, places and disposes, which limit the fine use of lacquer lipids. Firstly, constituents and physicochemical properties of lacquer berries of Rhus Succedanea L., seeding Rhus Succedanea L.from Jiangxi and grafting Rhus Succedanea L.from Jiangxi were studied. The results showed that the introduced lacquer trees contained more lacquer wax with a low iodine value. The chemical constituents of lacquer waxes are about the same except that the grafting lacquer trees have a low content of diacids. Studies on chemical constituents of lacquer oils showed that linoleic acid contained in seeding lacquer trees is the highest, which is 56.222 %.Secondly, lacquer waxes from Japan, ningdu of Jiangxi, pingli of Shaanxi and enshi of Hubei were studied. The relative content of palmitic acid is quite different, as it is 59.699 % in lacquer wax from Shaanxi, 50.685 % in lacquer wax from Japan. The totol contents of diacids in lacquer waxes from Hubei and Japan are the highest. The relative contents of other fatty acids are about the same.Lastly, lacquer oils under different pretreatments were studied. In this experimrnt, lacquer berries were selected and separated into two parts of pulp and seed kernels. Then parts of the seed kernels were aqueously washed while parts of them were soaked by petroleum ether. Lacquer oils were extracted from these seed kernels. Analysis showed that lacquer oils extracted from seed kernels after pretreatments are clear and light, the acid value and peroxide value are lower. And they contain 72 % of linoleic acid, while lacquer oils extracted from seed kernels without pretreatments contain many impurities.Thermal reflux processing was studied via single factor and orthogonal experiments. And the superior extraction conditions of lacquer wax were solvent of petroleum ether, twice of extraction times,1:20 of solid-liquid ratio, 60 min of extraction time, and 80℃of extraction temperature. Under these conditions, the yield of lacquer wax could reach 55.04 %.Decoloration by physical adsorption was widely used in oils as it won't change the qualities. In order to find the optimum conditions of lacquer wax decoloration, a physical adsorption decoloration method was used in single factor and orthogonal experiments under the thermal reflux and agitation conditions. The results indicate that the optimum decoloration conditions were using petroleum ether as solvent, activated carbon and kieselguhr (mass ratio 1:1)as adsorbent, whose ratio is 5%, with a solid-liquid ratio of 1:20, for 30 min at 80℃for twice. And the whiteness of lacquer wax can reach 85.25 by using this method. Meanwhile, studies on chromaticity values demonstrated that the adsorbent mainly adsorbed the carotenoid. Then the primary fatty acids and their relative contents of lacquer wax before and after decoloration were investigated. Results showed that the relative contents of palmitic acid, oleic acid and stearic acid changed slightly.Meanwhile, influence of UV light on the color and physicochemical properties of lacquer wax were studied. Cheap production equipments and low energy consumption make it more economical and environmental, even though it will change the phsicochemical properties of lacquer wax. The results showed that the effect of time was the most significant, and the longer the better, temperature had a smaller effect. Among the conditions of irradiated for 10 -80 h at 50, 60 and 70℃by a UV light of 400 W whose wave was 360~400 nm, a temperature of 60℃for 60 h was selected as the best conditions. Detection of chromatography showed that the main mechanism of UV decoloration was that conjugate hydrocarbyl of isoprene monomers contained in the natural pigment can absorb the energy of the visible light or ultraviolet to oxidize the double-bone, which made the chormophoric group fade when the structure of them were damaged. As a result of oxidization, the peroxide value increased while the iodine value decreased with the increase of irradiation time. Chemical constituents of the lacquer wax did not change significantly, except that the unsaturated fatty acids decreased as a result of oxidization.Compared to Japan wax, the unsaturated fatty acids contained in lacquer wax of China are higher. As a result, hydrogenation of lacquer wax included dose of Pt/C, time, temperature and hydrogen pressure were studied. Results showed that the optimal condition was reacting with a dose of Pd/C (5.0 %) of 0.2 % for 2~4 h at 100℃with 200 rpm under a hydrogen pressure of 0.5 MPa. According to the analysis of chemical constituents before and after hydrogenation, unsaturated fatty acids mostly converted into saturated fatty acids. And the chemical constituents became closer to the lacquer wax branded Star Cherry-A from shortage of wood wax joint venture.