Papers by Author: Yu Ping Liu

Abstract: A novel synthesis method of bromoalkanol at high selectivity from the monobromination of diol with aqueous HBr (48%) in toluene under microwave irradiation was reported in this paper. Based on orthogonal tests results, 10-bromo-1-decanol was synthesized in 53.5% yield and at 95.2% selectivity. Other six bromoalkanols were synthesized according to the above method in 40.9%-78.7% yield and at 90.5%-96.6% selectivity, which were as follows: 8-bromo-1-octanol, 9-bromo-1-nonanol, 11-bromo-1-undecanol, 12-bromo-1-dodecanol, 13-bromo-1-tridecanol and 14-bromo-1-tetradecanol.

Abstract: 1-(3,3-dimethylcyclohexyl) ethyl acetate was synthesized by the reaction of dihydromycene with acetic acid in the presence of sulfuric acid. The effecting factors including the amount of catalyst, the reaction temperature, the molar ratio of raw materials and the reaction time were investigated. The experimental results showed that the molar raio of the dihydromyrcene to acetic acid to sulfuric acid was 1:3:0.2, the reaction temperature is 60 °C and the reaction time was 6.5 h. The yield reached 45.3%. The structure of product was characterized by gas chromatography, mass spectrometry, infrared spectroscopy and nuclear magnetic resonance. The odor evaluation result indicated that the product had a sweet, woody, floral odor.

Abstract: Benzyl 4-ethyloctanoate was synthesized by the reaction of 4-ethyloctanoyl chloride with benzyl alcohol, and its synthesis conditions were optimized. The yield of benzyl 4-ethyloctanoate was about 93%. Based on the synthesis of benzyl 4-ethyloctanoate, phenethyl 4-ethyloctanoate, phenylpropanol 4-ethyloctanoate and cinnamyl 4-ethyloctanoate were prepared. The odor evaluations indicate that these four new ester compounds have floral and sweet note. These ester compounds have relatively high molecular weights and can be used as fixing agent to prolong the fragrance compounds lifetime.

Abstract: The volatile flavor compounds of Huizhou preserved vegetable were extracted by hydrodistillation (HD) and simultaneous distillation-extraction (SDE). The essential oils obtained were analyzed by gas chromatography-mass spectrometry, accompanying by comparison of the retention time of authentic samples and by calculation of retention index about the separated constituents. 50 volatile flavor compounds were identified in the essential oils of Huizhou preserved vegetable obtained by HD and SDE in all. 41 compounds were identified in the essential oil from HD and 36 compounds identified in the essential oil from SDE. The constituents which are very important to the odor of Huizhou preserved vegetable include 3-hydroxy-2-butanone, dimethyl disulfide, hexanal, furfural, 2-furanmethanol, 2-methylbutanoic acid, benzeneacetaldehyde, phenylethyl alcohol, 5-ethyldihydro-2(3H)-furanone, 5-pentyl-dihydro-2(3H)-furanone, etc. The exclusive compounds in the essential oil gained by HD consist of hexanol, heptanol, 1-(2-furanyl)-ethanone, 5-methyl-dihydro-2(3H)-furanone, benzaldehyde, phenol, benzyl alcohol, methyl benzoate, ethyl benzoate. The exclusive compounds obtained by SDE are 3-hydroxy-2-butanone, dimethyl trisulfide, trans-2-(2-pentenyl)-furan, camphor, vanillin, etc. The differences result in the two essential oils with a few distinctions on aroma characteristics.