Min Zheng,Xiangzhou Li,Dulin Yin,Steven R. Kirk,Hui Li,Peng Zhou,Yanhong Yang
Carveol is a rare fine chemical with specific biological activities and functions in nature. The artificial synthesis of carveol from plentiful and cheap turpentine is expected to further improve development of pharmaceutical and industrial applications. A new green catalytic system for the preparation of high-value carveol from α-epoxypinane is presented. A novel ammonium salt solid acid (AC-COIMI-NH4PW) was obtained from phosphotungstic acid bonded with imidazole basic site on nitrogen-doped activated carbon which, after ammonia fumigation, presented an excellent catalytic performance for the selective rearrangement of α-epoxypinane to carveol in DMF as solvent under mild reaction conditions. At 90 °C for 2 h, the conversion of α-epoxypinane could reach 98.9% and the selectivity of carveol was 50.6%. The acidic catalytic sites exhibited superior durability and the catalytic performance can be restored by supplementing the lost catalyst. Based on the investigation of catalytic processes, a parallel catalytic mechanism for the main product was proposed from the rearrangement of α-epoxypinane on AC-COIMI-NH4PW.
Tianyu Dong,Zilong Tian,Shuwei Wang,Jie Sun,Haitao Chen,Shuqi Wang,Baoguo Sun
Fried pepper oil (FPO) is a widely used flavoring oil in China, but it suffers from complex chemical reactions that give an unpleasant odor. The aim of this paper is to study the main causes of off-flavor in FPO, as well as identify key off-flavor compounds in FPO. Fifty-eight volatiles were identified using HS-SPME–GC–MS (headspace solid-phase microextraction–gas chromatography–mass spectrometry) during storage. Fifteen off-flavor compounds were initially targeted by odor activity values (OAVs) calculations and partial least squares regression (PLSR) analysis. Eventually, five key off-flavor compounds were identified by recombination experiments and omission test, which were hexanal, ( E ) - 2-octenal, terpinyl acetate, α -terpineol, and hexanoic acid. The off-flavors could derive from the oxidative degradation of long-chain fatty acids and the acid-catalyzed rearrangement of terpenes. The results of the study provide a theoretical basis for the regulation of off-flavor in FPO and a practical guide for the industrial production of FPO.
Yumei Shu,Xiaoyu Wang,Tinghao Jia,Lun Pan,Qingfa Wang,Xiangwen Zhang,Ji-Jun Zou
Biomass-based aviation fuel is attractive for sustainable development. Herein, we report a facile route to synthesize alkyl-adamantanes (AAMs) via acid-catalyzed rearrangement of biomass polycyclic sesquiterpene derivatives (bio-PCS derivatives). The reaction conditions including catalysts, solvents, reaction temperature and reaction time were optimized. Notably, a total AAMs yield of 65.1% was achieved under the optimal conditions. The kinetics of rearrangement reaction was investigated, and the reaction rate constant ( k ) and apparent activation energy ( E a ) were calculated based on the experimental kinetic data. The rearrangement products possess high density of 0.90 g/cm 3 , high net heat of combustion of 42.6 MJ/kg, low viscosity (22.5 mm 2 /s at −20℃) and high thermal oxidative stability. The blending of rearrangement products with JP-10 can significantly shorten the ignition delay time (IDT) of JP-10. This work provides a method to synthesize high-performance biomass-based AAMs.
危险品化学品经营许可证（带存储）