Li Wang,Jun Xiang,Songhang Wang,Zhe Sun,Jiating Wen,Jing Li,Zhong Zheng,Haojun Fan
Oleic acid , as a renewable resource, exists in almost every vegetable oil, especially olive and camellia oils, which has promising prospects for the preparation of bio-based polymers. In this study, a novel oleic-based primary glycol (OPG) was synthesized from methyl oleate (MO, derived from vegetable oil) via Claisen condensation and thiol-ene photo-click reactions and used as an alternative to petroleum-based glycol for the preparation of bio-based waterborne polyurethane (BWPU), and the differences in reactivity between the OPG and petroleum-based polypropylene glycol (PPG) and properties between BWPU and petroleum-based waterborne polyurethane (PWPU) were investigated. The yield of OPG was approximately 90%, the degree of functionality was 2.0, the hydroxyl value was about 155 mg KOH g −1 and the molecular weight (M w ) varied from 296 g mol −1 to 560 g mol −1 and 716 g mol −1 after the chain extension of Claisen condensation and thiol-ene photo-click reactions. In comparison with PPG, OPG exhibited lower activation energy towards IPDI, and the values showed an order of OPG ( E a / E o =71.25/74.20 kJ mol −1 ) < PPG600 ( E a / E o =106.83/108.03 kJ mol −1 ) < PPG1000 ( E a / E o =129.20/129.37 kJ mol −1 ). Correspondingly, the end point of pre-polymerization appeared in 80 min for OPG and 420 min, 840 min for PPG600 and PPG1000 at 80 °C without catalyst, demonstrating that OPG had higher reactivity. Because of the difference in hydrophobicity, the minimum amount of hydrophilic extender used to obtain stable WPU emulsions was 7 wt% for OPG and 3.5 wt% for PPG respectively. The resulting BWPU films possessed good mechanical properties, including higher tensile strength (19.78 MPa) and Young’s modulus (206.61 MPa). But the thermal stability (T d5% ≤ 250 ℃) and low temperature resistance (T g ≥ 28 ℃) of BWPU films were inferior to that of PWPU films.
Wuyu Wang,Xuelai Zhao,Yanyan Cui,Xinghua Zhang,Lungang Chen,Qi Zhang,Longlong Ma
Jet fuels must simultaneously meet stringent requirements for energy density and freezing point to ensure safe operation under extreme flight conditions. The common technical route of biojet fuel is hydrodeoxidation after the platform molecule C–C coupling. The branched long-chain alkanes synthesized from biomass-derived C5–C6 esters and ketones platform molecules can meet the performance requirements of jet fuel, via the Claisen condensation as the C–C coupling step. The acetone-derived methyl isobutyl ketone (MIBK) and methyl pivalate were efficiently converted to C11 fuel precursor with branched chain structure over potassium tert-butoxide (t-BuOK) in N,N-dimethylformamide solution. MIBK was fully converted at room temperature for 7 h, with a 95% yield of C11 oxygenated compounds. Under the same conditions, a series of C10–12 oxygenated compounds with a yield around 80% could be synthesized from methyl pivalate and other ketones. In addition, the oxygenated compounds generated alongside the Claisen condensation reaction could serve as jet fuel precursors, thereby ensuring high atomic economy of ketones. After hydrodeoxygenation, these oxygenated precursors are transformed into isomeric alkanes with freezing points below −100 °C, meeting and even surpassing aviation fuel standards. Importantly, the mild conditions, high selectivity, and compatibility with a wide range of ketone feedstocks indicate the route’s strong industrial application potential for large-scale production of ultralow freezing biojet fuel for extreme aviation environments.
危险品化学品经营许可证（带存储）