Sulfamic acid has been used as an efficient catalyst and green alternative for conventional acidic materials to promote the acetolysis reaction of THF to produce 1, 4-diacetoxybutane. This method is also applicable in...Sulfamic acid has been used as an efficient catalyst and green alternative for conventional acidic materials to promote the acetolysis reaction of THF to produce 1, 4-diacetoxybutane. This method is also applicable in the acetolysis of other cyclic ethers, such as methyl substituted THF and tetrahydropyran and 1,4-dioxane which is less reactivity.展开更多
Carbon or glass fibre-reinforced epoxy-amine resins are vital for lightweight and durable applications in wind energy,aerospace,and sports.However,their recycling has long been a challenge due to the presence of cross...Carbon or glass fibre-reinforced epoxy-amine resins are vital for lightweight and durable applications in wind energy,aerospace,and sports.However,their recycling has long been a challenge due to the presence of cross-linked polymer networks.The global composites market is forecast to reach nearly 15 million tonnes by 2027[1],creating an urgent need for a technically and economically feasible strategy to manage the growing volume of fibrereinforced polymer waste.展开更多
The acetolysis technology for waste polyester fibers is characterized by simplicity, efficiency, and cost-effectiveness.However, challenges emerge when processing polyester-cotton blends, as the cotton component canno...The acetolysis technology for waste polyester fibers is characterized by simplicity, efficiency, and cost-effectiveness.However, challenges emerge when processing polyester-cotton blends, as the cotton component cannot enduremore aggressive chemical conditions due to its distinct chemical properties. To overcome this, we now employthe concept of "acetylation" for a mild cotton-stripping pretreatment. During acetylation, the cotton componentgradually dissolves in the acetic acid solution, forming a homogeneous solution, while the polyester fiber remainsin solid form, thereby ensuring efficient separation (removal rate exceeding 90%). The entire process utilizes inexpensivebulk chemicals and is straightforward to operate. Given the similarity in the solvent system, this approachis termed the extended acetolysis system. Comprehensive techno-economic analysis and life cycle assessmentindicate that, even when benchmarked against petroleum-based pricing, the extended acetolysis system can achieveeconomic viability alongside appreciable environmental benefits.展开更多
To investigate the chemical structure of cell wall mannan of pathogenic yeast, Candida catenulata IFO 0745 strain, which possess the epitopes of antigenic factors 1, 9, and 34 to genus Candida, we previously performed...To investigate the chemical structure of cell wall mannan of pathogenic yeast, Candida catenulata IFO 0745 strain, which possess the epitopes of antigenic factors 1, 9, and 34 to genus Candida, we previously performed the two-dimensional nuclear magnetic resonance (NMR) analysis of this mannan, Fr. C, without the need for harsh procedures. In this study, three oligosaccharides, biose, triose, and tetraose, and mannose were isolated from Fr. C by acetolysis. The results of NMR analysis indicate that the chemical structures of these oligosaccharides were identified to Manα1-2Man, Manα1-2Manα1-2Man, and Manα1-3Manα1-2Manα1-2Man. The most of resultant mannose seems to be originated from the α-1,6-linked mannan backbone which is recognized by antiserum to factor 9. The inhibition assay of slide agglutination reaction between Fr. C and antigenic antibodies using three oligosaccharides indicate that the Manα1-2Manα1-2Man and Manα1-3Manα1-2Manα1-2Man possess domains corresponding to immunodominants of antigenic factors 1 and 34, respectively.展开更多
To investigate the chemical structure of cell wall mannan obtained from pathogenic yeast, Candida tropicalis NBRC 1400 (former antigenic standard strain, IFO 1400). As a result of two-dimensional NMR analysis, it was ...To investigate the chemical structure of cell wall mannan obtained from pathogenic yeast, Candida tropicalis NBRC 1400 (former antigenic standard strain, IFO 1400). As a result of two-dimensional NMR analysis, it was shown that the mannan of this strain is composed of α-1,6-, α-1,3-, α-1,2- and β-1,2-linked mannose residues. In this research, the mannan was subjected to three degradation procedures, acid-treatment, α-mannosidase, and acetolysis under two conditions in order to determine the chemical structure of the antigenic oligomannosyl side chains in this molecule. The 1H-nuclear magnetic resonance spectra of resultant oligosaccharides, pentaose and hexaose, demonstrated the existence of the oligomannosyl side chains corresponding to Manα1-3Manα1-2Manα1-2Manα1-2Man and Manα1-3Manα1-2Manα1-2Manα1-2Manα1-2Man, respectively, which have previously also been found in Candida albicans serotype A strain mannans. These findings indicate that C. tropicalis and C. albicans serotype A have no significant difference in the chemical structure of these cell wall mannans. Therefore, it can be interpreted that it is extremely difficult to distinguish both species by targeting the antigenic group in these mannans.展开更多
文摘Sulfamic acid has been used as an efficient catalyst and green alternative for conventional acidic materials to promote the acetolysis reaction of THF to produce 1, 4-diacetoxybutane. This method is also applicable in the acetolysis of other cyclic ethers, such as methyl substituted THF and tetrahydropyran and 1,4-dioxane which is less reactivity.
文摘Carbon or glass fibre-reinforced epoxy-amine resins are vital for lightweight and durable applications in wind energy,aerospace,and sports.However,their recycling has long been a challenge due to the presence of cross-linked polymer networks.The global composites market is forecast to reach nearly 15 million tonnes by 2027[1],creating an urgent need for a technically and economically feasible strategy to manage the growing volume of fibrereinforced polymer waste.
基金National Natural Science Foundation of China(22279125,22478374),Anhui Provincial Development and Reform Commission’s 2023 Task List for Enhancing Industrial Fundamental Capabilities:Chemical Depolymerization Processes and Equipment for Polyester Materials.
文摘The acetolysis technology for waste polyester fibers is characterized by simplicity, efficiency, and cost-effectiveness.However, challenges emerge when processing polyester-cotton blends, as the cotton component cannot enduremore aggressive chemical conditions due to its distinct chemical properties. To overcome this, we now employthe concept of "acetylation" for a mild cotton-stripping pretreatment. During acetylation, the cotton componentgradually dissolves in the acetic acid solution, forming a homogeneous solution, while the polyester fiber remainsin solid form, thereby ensuring efficient separation (removal rate exceeding 90%). The entire process utilizes inexpensivebulk chemicals and is straightforward to operate. Given the similarity in the solvent system, this approachis termed the extended acetolysis system. Comprehensive techno-economic analysis and life cycle assessmentindicate that, even when benchmarked against petroleum-based pricing, the extended acetolysis system can achieveeconomic viability alongside appreciable environmental benefits.
文摘To investigate the chemical structure of cell wall mannan of pathogenic yeast, Candida catenulata IFO 0745 strain, which possess the epitopes of antigenic factors 1, 9, and 34 to genus Candida, we previously performed the two-dimensional nuclear magnetic resonance (NMR) analysis of this mannan, Fr. C, without the need for harsh procedures. In this study, three oligosaccharides, biose, triose, and tetraose, and mannose were isolated from Fr. C by acetolysis. The results of NMR analysis indicate that the chemical structures of these oligosaccharides were identified to Manα1-2Man, Manα1-2Manα1-2Man, and Manα1-3Manα1-2Manα1-2Man. The most of resultant mannose seems to be originated from the α-1,6-linked mannan backbone which is recognized by antiserum to factor 9. The inhibition assay of slide agglutination reaction between Fr. C and antigenic antibodies using three oligosaccharides indicate that the Manα1-2Manα1-2Man and Manα1-3Manα1-2Manα1-2Man possess domains corresponding to immunodominants of antigenic factors 1 and 34, respectively.
文摘To investigate the chemical structure of cell wall mannan obtained from pathogenic yeast, Candida tropicalis NBRC 1400 (former antigenic standard strain, IFO 1400). As a result of two-dimensional NMR analysis, it was shown that the mannan of this strain is composed of α-1,6-, α-1,3-, α-1,2- and β-1,2-linked mannose residues. In this research, the mannan was subjected to three degradation procedures, acid-treatment, α-mannosidase, and acetolysis under two conditions in order to determine the chemical structure of the antigenic oligomannosyl side chains in this molecule. The 1H-nuclear magnetic resonance spectra of resultant oligosaccharides, pentaose and hexaose, demonstrated the existence of the oligomannosyl side chains corresponding to Manα1-3Manα1-2Manα1-2Manα1-2Man and Manα1-3Manα1-2Manα1-2Manα1-2Manα1-2Man, respectively, which have previously also been found in Candida albicans serotype A strain mannans. These findings indicate that C. tropicalis and C. albicans serotype A have no significant difference in the chemical structure of these cell wall mannans. Therefore, it can be interpreted that it is extremely difficult to distinguish both species by targeting the antigenic group in these mannans.
