MOLECULES
·
2023
·Vol. 28
·期 12
·4723
·
IF 4.6
Rongxiu Qin,Haiyan Chen,Rusi Wen,Guiqing Li,Zhonglei Meng
To investigate the synergistic catalytic effects of boric acid and α-hydroxycarboxylic acids (HCAs), we analyzed and measured the effects of the complexation reactions between boric acid and HCAs on the ionization equilibrium of the HCAs. Eight HCAs, glycolic acid, D-(−)-lactic acid, (R)-(−)-mandelic acid, D-gluconic acid, L-(−)-malic acid, L-(+)-tartaric acid, D-(−)-tartaric acid, and citric acid, were selected to measure the pH changes in aqueous HCA solutions after adding boric acid. The results showed that the pH values of the aqueous HCA solutions gradually decreased with an increase in the boric acid molar ratio, and the acidity coefficients when boric acid formed double-ligand complexes with HCAs were smaller than those of the single-ligand complexes. The more hydroxyl groups the HCA contained, the more types of complexes could be formed, and the greater the rate of change in the pH. The total rates of change in the pH of the HCA solutions were in the following order: citric acid > L-(−)-tartaric acid = D-(−)-tartaric acid > D-gluconic acid > (R)-(−)-mandelic acid > L-(−)-malic acid > D-(−)-lactic acid > glycolic acid. The composite catalyst of boric acid and tartaric acid had a high catalytic activity—the yield of methyl palmitate was 98%. After the reaction, the catalyst and methanol could be separated by standing stratification.Keywords:boric acid;α-hydroxycarboxylic acid;ionization equilibrium;fatty acid esterification;green synthesis
研究领域:
化学
·
催化
·
绿色化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SYNTHESIS-STUTTGART
·
2015
·Vol. 47
·期 23
·3751-3757
·
IF 2.689
Zhijie Li,Quan Wen,Lihong Zhou,Xingmei Deng,Qingle Zeng
The synthesis of highly important α-hydroxycarboxylic acid anilides via copper-catalyzed chemoselective C–N coupling reactions of α-hydroxyamides and aryl halides is described. This highly selective N-arylation process demonstrates wide substrate scope, cost savings and easy operation. In addition, the chirality of l-3-phenyllactamide is preserved during the reaction.
研究领域:
有机化学
·
合成化学
✓ 已验证
DOI
高影响因子
MOLECULES
·
2023
·Vol. 28
·期 4
·1875
·
IF 4.6
Zhong-Lei Meng,Rong-Xiu Qin,Ru-Si Wen,Gui-Qing Li,Zhong-Yun Liang,Jun-Kang Xie,Yong-Hong Zhou,Zhang-Qi Yang
This study examined the preparation of isobornyl acetate/isoborneol from camphene using an α-hydroxyl carboxylic acid (HCA) composite catalyst. Through the study of the influencing factors, it was found that HCA and boric acid exhibited significant synergistic catalysis. Under optimal conditions, when tartaric acid–boric acid was used as the catalyst, the conversion of camphene and the gas chromatography (GC) content and selectivity of isobornyl acetate were 92.9%, 88.5%, and 95.3%, respectively. With the increase in the ratio of water to acetic acid, the GC content and selectivity of isobornol in the product increased, but the conversion of camphene decreased. The yield of isobornol was increased by adding ethyl acetate or titanium sulfate/zirconium sulfate to form a ternary composite catalyst. When a ternary complex of titanium sulfate, tartaric acid, and boric acid was used as the catalyst, the GC content of isobornol in the product reached 55.6%. Under solvent-free conditions, mandelic acid–boric acid could catalyze the hydration reaction of camphene, the GC content of isoborneol in the product reached 26.1%, and the selectivity of isoborneol was 55.9%. The HCA–boric acid composite catalyst can use aqueous acetic acid as a raw material, which is also beneficial for the reuse of the catalyst.Keywords:α-hydroxyl carboxylic acid;camphene esterification reaction;camphene hydration reaction;green synthesis
研究领域:
化学
·
催化
·
有机合成
·
绿色化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PLoS One
·
2024
·Vol. 19
·期 4
·e0299218
·
IF 2.9
Zhonglei Meng,Rongxiu Qin,Rusi Wen,Junkang Xie,Guiqing Li,Yonghong Zhou
To enhance the yield of the one-step synthesis of terpinyl acetate from α-pinene and acetic acid, this study evaluated α-hydroxycarboxylic acid (HCA)–boric acid composite catalysts based on orthogonal experimental design. The most important factor affecting the terpinyl acetate content in the product was the HCA content. The catalytic performance of the composite catalyst was related to the pKa1 of HCA. The tartaric acid–boric acid composite catalyst showed the highest catalytic activity. The α-pinene conversion reached 91.8%, and the terpinyl acetate selectivity reached 45.6%. When boric acid was replaced with B2O3, the HCA composite catalyst activity was enhanced, which reduced the use of HCA. When the lactic acid and B2O3 content accounted for 10% and 4% of the α-pinene mass content, respectively, the α-pinene conversion reached 93.2%, and the terpinyl acetate selectivity reached up to 47.1%. In addition, the presence of water was unfavorable to HCA–boric acid composite catalyst. However, a water content less than 1% of the α-pinene mass content improved the catalytic activity of HCA–B2O3. When the tartaric acid–B2O3 was used as catalyst, and the water content was 1% of the α-pinene mass content, the α-pinene conversion was 89.6%, and the terpinyl acetate selectivity was 47.5%.
研究领域:
化学工程
·
催化
·
有机化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MOLECULES
·
2023
·Vol. 28
·期 7
·3202
·
IF 4.6
Zhonglei Meng,Rongxiu Qin,Rusi Wen,Guiqing Li,Zhongyun Liang,Junkang Xie,Zhangqi Yang,Yonghong Zhou
In this study, seven types of α-hydroxycarboxylic acids were selected to form composite catalysts with boric acid, and their catalytic properties were studied using the catalytic hydration of α-pinene. The results showed that the composite catalyst of boric acid and tartaric acid had the highest catalytic activity. With an α-pinene, water, acetic acid, tartaric acid, and boric acid mass ratio of 10:10:25:0.5:0.4, the reaction temperature was 60 °C, the reaction time was 24 h, the conversion of α-pinene was 96.1%, and the selectivity of terpineol was 58.7%. The composite catalyst composed of boric acid and mandelic acid directly catalyzed the hydration of α-pinene in the absence of a solvent. Under the optimal conditions, the conversion of α-pinene reached 96.1%, and the selectivity of terpineol was 55.5%. When the composite catalyst catalyzed α-pinene to synthesize terpineol in one step, the terpineol was optically active, and terpineol synthesized using the two-step method with the dehydration ofp-menthane-1,8-diol monohydrate was racemic. These composite catalysts may offer good application prospects in the synthesis of terpineol.Keywords:α-hydroxycarboxylic acid–boric acid complexes;green catalyst;hydration of α-pinene;solvent-free;terpineol;p-menthane-1,8-diol monohydrate
研究领域:
催化
·
有机化学
·
绿色化学
✓ 已验证
DOI
PubMed
高影响因子
POLYMER BULLETIN
·
2016
·Vol. 74
·期 4
·1061-1076
·
IF 1.371
Yong Qiwen,Nian Fuwei,Liao Bing,Guo Ying,Huang Liping,Wang Lu,Pang Hao
Self-matt coating of waterborne polyurethane (WBPU) was synthesized by combining prepolymer and self-emulsification methods. The emulsion was fabricated from both hydroxy carboxylic acid and aminosulfonic acid types of hydrophilic chain-extending agents, in which the 2-[(2-aminoethyl) amino] ethane sulphonate sodium (AAS salt) was produced in laboratory. This emulsion demonstrated an excellent matt performance without the addition of extra matting agents after filming. Four different kinds of surface properties were measured on the film: the specular gloss (60° gloss meter), the contact angle (CA), the surface roughness degree (3D Surface Profilometer), and the topography of the coatings surface (SEM). The results showed that tons of spherical particles with diameter in a few micrometers were aggregated on the film surface. The effect of the roughness parameters ( R
a
and R
q
) and the average particle size of the emulsions on the specular gloss degree were probed. The research indicated that the emulsion with average particle size in the range of 2.5–3.0 µm and, meanwhile, the film with roughness parameters R
a
and R
q
both greater than 1 µm could attain the best matt effect. The WBPU emulsions showed good physical and mechanical properties, and were introduced into wood varnish for matting purpose.
研究领域:
材料科学
·
化学工程
·
表面化学
·
高分子科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）