The novel solid acid with both sulfonic and carbonyl acid groups has been synthesized from 3-((2-sulfoethoxy) carbonyl)acrylic acid and tetraethyl orthosilicate(TEOS). The catalytic activities were investigated throug...The novel solid acid with both sulfonic and carbonyl acid groups has been synthesized from 3-((2-sulfoethoxy) carbonyl)acrylic acid and tetraethyl orthosilicate(TEOS). The catalytic activities were investigated through the acetalization. The results showed that the novel solid acid was very efficient for the reactions with the high yields. The high acidity, high stability and reusability were the key feature of the novel solid acid. Moreover, the sulfonic and carbonyl acid groups could cooperate during the catalytic process, which improved its catalytic activities. The catalyst shows recyclability, and hold great potential for replacement of homogeneous catalysts.展开更多
In this study,sulfonic acid-functionalized lignin-montmorillonite complex(LMT-SO_(3)H)was pre-pared and employed as an efficient heterogeneous catalyst for the esterification of levulinic acid(LA)into n-butyl levulina...In this study,sulfonic acid-functionalized lignin-montmorillonite complex(LMT-SO_(3)H)was pre-pared and employed as an efficient heterogeneous catalyst for the esterification of levulinic acid(LA)into n-butyl levulinate(BL).An intermediate pseudo-butyl levulinate(p-BL)was determined by distilled water treatment and nuclear magnetic resonance(NMR)analysis,and a possible mech-anism for the esterification of LA is proposed.The effects of various process parameters were studied and the results showed that the LMT-SO_(3)H catalyst had the excellent catalytic perfor-mance for esterification of the LA.Under optimum reaction conditions,the yield of BL was 99.3%and the conversion of LA was 99.8%.The LMT-SO_(3)H catalyst exhibited strong acidic sites and high stability even after seven cycles of usage.Furthermore,esterification of the LA with various alcohols over the LMT-SO_(3)H was further investigated.展开更多
Various alcohols and phenols were trimethylsilylated in excellent yields using hexamethyldisilazane in the presence of catalytic amounts of environmentally friendly, hydrophobic, highly thermal stable, and completely ...Various alcohols and phenols were trimethylsilylated in excellent yields using hexamethyldisilazane in the presence of catalytic amounts of environmentally friendly, hydrophobic, highly thermal stable, and completely heterogeneous sulfonic acid functionalized mesostructured SBA-15 in dichloromethane at ambient temperature. Primary, bulky secondary, tertiary, and phenolic hydroxyl functional groups were transformed to the corresponding trimethylsilyl ethers in excellent yields. The simple experimental procedure was accompanied by easy recovery and the catalyst was reusable (at least 18 reaction cycles); these are attractive features of this protocol.展开更多
基金Supported by the Chinese National General Administration of Quality Supervision,Inspection and Quarantine(2012IK048,2011IK041)the National Natural Science Foundation of China(21103111)
文摘The novel solid acid with both sulfonic and carbonyl acid groups has been synthesized from 3-((2-sulfoethoxy) carbonyl)acrylic acid and tetraethyl orthosilicate(TEOS). The catalytic activities were investigated through the acetalization. The results showed that the novel solid acid was very efficient for the reactions with the high yields. The high acidity, high stability and reusability were the key feature of the novel solid acid. Moreover, the sulfonic and carbonyl acid groups could cooperate during the catalytic process, which improved its catalytic activities. The catalyst shows recyclability, and hold great potential for replacement of homogeneous catalysts.
基金the financial support of the National Natural Science Foundation of China(Nos.21606082,21776068 and 21975070)Hunan Provincial Natural Science Foundation of China(No.2018JJ3334),and China Postdoctoral Science Foundation(No.2019M662787).
文摘In this study,sulfonic acid-functionalized lignin-montmorillonite complex(LMT-SO_(3)H)was pre-pared and employed as an efficient heterogeneous catalyst for the esterification of levulinic acid(LA)into n-butyl levulinate(BL).An intermediate pseudo-butyl levulinate(p-BL)was determined by distilled water treatment and nuclear magnetic resonance(NMR)analysis,and a possible mech-anism for the esterification of LA is proposed.The effects of various process parameters were studied and the results showed that the LMT-SO_(3)H catalyst had the excellent catalytic perfor-mance for esterification of the LA.Under optimum reaction conditions,the yield of BL was 99.3%and the conversion of LA was 99.8%.The LMT-SO_(3)H catalyst exhibited strong acidic sites and high stability even after seven cycles of usage.Furthermore,esterification of the LA with various alcohols over the LMT-SO_(3)H was further investigated.
文摘Various alcohols and phenols were trimethylsilylated in excellent yields using hexamethyldisilazane in the presence of catalytic amounts of environmentally friendly, hydrophobic, highly thermal stable, and completely heterogeneous sulfonic acid functionalized mesostructured SBA-15 in dichloromethane at ambient temperature. Primary, bulky secondary, tertiary, and phenolic hydroxyl functional groups were transformed to the corresponding trimethylsilyl ethers in excellent yields. The simple experimental procedure was accompanied by easy recovery and the catalyst was reusable (at least 18 reaction cycles); these are attractive features of this protocol.
