Mobile phones represent a significant and growing problem with respect to electrical waste and electronic equipment (WEEE). Nevertheless, they are perhaps one of the most valuable electronic products, since they are a...Mobile phones represent a significant and growing problem with respect to electrical waste and electronic equipment (WEEE). Nevertheless, they are perhaps one of the most valuable electronic products, since they are an important resource for the recovery of metals in terms of mass and volume. In this research a chemical recycling of mobile phones by solvolysis was investigated. The processing was performed by comminution in a hammer mill followed by screening to obtain mesh-4 sized flakes. Flakes were subjected to solvolysis. Different reaction conditions were tested. A reaction time between 2 - 7 hours and a temperature between 150°C - 300°C were the optimum conditions to dissolve the polymer contained in mobile phones. Metals were separated by filtration. Chemical analyses (ATR FT-IR, UV) were carried out on the solvent and the mobile phone flakes before and after solvolysis. A SEM study was carried out, before and after solvolysis, but only to the mobile phone flakes. Thermal transitions of mobile phone flakes were determined by DSC. Chemical results showed that some aromatic species migrate from mobile phones flakes to the solvent, due to the solvolysis reaction. Thermal analysis showed that the Tg, (glass transition temperature) of mobile phone flakes after solvolysis was different to Tg of the polymer before solvolysis, this is due to chemical changes in the molecule. A comparative SEM study revealed that, after solvolysis, the polymer contained in mobile phone flakes is more elastomeric. After solvolysis, solvent was recovered by means of a rotatory evaporator, so that it can be used again. The results obtained in this research showed that solvolysis is an alternative for metal recovery from mobile phones.展开更多
Rates of solvolyses of 2-（4-methylphenyl）-2-propyl benzoate （2b）, 2-（4-methylthiopheny1）-2-propyl benzoate （3b） and 2,2-dimethy1-1-（4-methoxypheny1）-1-phenyl-1-propy1 benzoate （4b） were measured, respectiv...Rates of solvolyses of 2-（4-methylphenyl）-2-propyl benzoate （2b）, 2-（4-methylthiopheny1）-2-propyl benzoate （3b） and 2,2-dimethy1-1-（4-methoxypheny1）-1-phenyl-1-propy1 benzoate （4b） were measured, respectively, in ten or more different solvent systems. Additional YBnOPXB and Y, BnOPNB values in binary trifluoroethanol-water systems were determined, Grunwald-Winstein type correlation analysis showed that YBaIOBB values were applicable to benzylic benzoates. The rate ratio, koPNB/KOBZ, was found to be solvent-dependent in the range of 29 for 4 in ethanol to 4 for 2 in trifluoroethanol-water. Non-limiting mechanism, including both nucleophilic and electrophilic solvent assistance, in the solvolysis of 2b was discussed,展开更多
Grandiflorenic acid(1),possessing potent contragestational activity,is an ent-kauranediterpenoid.It has been isolated from Mexical medicinal plant zoapatle(Montanoa tomento)In connection with our synthetic work on ent...Grandiflorenic acid(1),possessing potent contragestational activity,is an ent-kauranediterpenoid.It has been isolated from Mexical medicinal plant zoapatle(Montanoa tomento)In connection with our synthetic work on ent-kaurane diterpenoids,we are interested in theconversion of stevioside(2)occurred abundantly in Stevia rebaudiana into grandiflorenic acid展开更多
Nucleophilic substitution of ferrocenyl alcohols with various aliphatic alcohols in the presence of a catalytic amount of ytterbium triflate [Yb（OTf）3] was studied. It was found the unsymmetrical ferrocenyl ethers c...Nucleophilic substitution of ferrocenyl alcohols with various aliphatic alcohols in the presence of a catalytic amount of ytterbium triflate [Yb（OTf）3] was studied. It was found the unsymmetrical ferrocenyl ethers could be easily obtained in excellent yields when the reactions were performed in primary and secondary alcohols. However, in other organic non-alcoholic solvents such as acetonitrile, the formation of symmetrical ferrocenyl ethers rather than unsymmetrical ones was observed.展开更多
The solvolysis of ammonia borane(AB)and the hydrogenation of nitroarenes represent significant reactions for hydrogen generation and value-added chemical synthesis.The strategic engineering of the catalysts is imperat...The solvolysis of ammonia borane(AB)and the hydrogenation of nitroarenes represent significant reactions for hydrogen generation and value-added chemical synthesis.The strategic engineering of the catalysts is imperative for surmounting obstacles associated with their stability and catalytic efficiency.In this work,subnanometric bimetallic Pt–Pd clusters were encapsulated within silicalite-1(S-1)zeolites through a ligand-protected in-situ hydrothermal synthesis method.The synergetic effect of bimetallic composition and zeolite confinement markedly enhances the catalytic performance of representative Pt_(0.5)Pd_(0.5)@S-1-H catalyst,affording exceptional turnover frequency(TOF)values of 1,043 and 573 mol_(H_(2))mol_(metal)^(-1)min^(-1)for AB hydrolysis and methanolysis at ambient conditions,respectively,surpassing most of the state-of-the-art Pt-based catalysts.Kinetic and isotopic experiments reveal that the bimetallic catalytic system remarkably boosts the O-H cleavage of water,thereby facilitating the H_(2) production from AB hydrolysis.Remarkably,a conspicuous synergistic effect is demonstrated in the shape-selective tandem hydrogenation of nitroarenes,with the bimetallic catalyst facilitating both AB hydrolysis and nitroarene hydrogenation,giving a high TOF value of 1,260 h^(-1)under atmospheric pressure.This study not only demonstrates the effectiveness of bimetallic nanocatalysts encapsulated in zeolites for hydrogen production from chemical hydrogen storage materials,but also paves the way for the design of catalysts with multifunctional active sites capable of synergistically promoting tandem catalytic processes.展开更多
文摘Mobile phones represent a significant and growing problem with respect to electrical waste and electronic equipment (WEEE). Nevertheless, they are perhaps one of the most valuable electronic products, since they are an important resource for the recovery of metals in terms of mass and volume. In this research a chemical recycling of mobile phones by solvolysis was investigated. The processing was performed by comminution in a hammer mill followed by screening to obtain mesh-4 sized flakes. Flakes were subjected to solvolysis. Different reaction conditions were tested. A reaction time between 2 - 7 hours and a temperature between 150°C - 300°C were the optimum conditions to dissolve the polymer contained in mobile phones. Metals were separated by filtration. Chemical analyses (ATR FT-IR, UV) were carried out on the solvent and the mobile phone flakes before and after solvolysis. A SEM study was carried out, before and after solvolysis, but only to the mobile phone flakes. Thermal transitions of mobile phone flakes were determined by DSC. Chemical results showed that some aromatic species migrate from mobile phones flakes to the solvent, due to the solvolysis reaction. Thermal analysis showed that the Tg, (glass transition temperature) of mobile phone flakes after solvolysis was different to Tg of the polymer before solvolysis, this is due to chemical changes in the molecule. A comparative SEM study revealed that, after solvolysis, the polymer contained in mobile phone flakes is more elastomeric. After solvolysis, solvent was recovered by means of a rotatory evaporator, so that it can be used again. The results obtained in this research showed that solvolysis is an alternative for metal recovery from mobile phones.
文摘Rates of solvolyses of 2-（4-methylphenyl）-2-propyl benzoate （2b）, 2-（4-methylthiopheny1）-2-propyl benzoate （3b） and 2,2-dimethy1-1-（4-methoxypheny1）-1-phenyl-1-propy1 benzoate （4b） were measured, respectively, in ten or more different solvent systems. Additional YBnOPXB and Y, BnOPNB values in binary trifluoroethanol-water systems were determined, Grunwald-Winstein type correlation analysis showed that YBaIOBB values were applicable to benzylic benzoates. The rate ratio, koPNB/KOBZ, was found to be solvent-dependent in the range of 29 for 4 in ethanol to 4 for 2 in trifluoroethanol-water. Non-limiting mechanism, including both nucleophilic and electrophilic solvent assistance, in the solvolysis of 2b was discussed,
文摘Grandiflorenic acid(1),possessing potent contragestational activity,is an ent-kauranediterpenoid.It has been isolated from Mexical medicinal plant zoapatle(Montanoa tomento)In connection with our synthetic work on ent-kaurane diterpenoids,we are interested in theconversion of stevioside(2)occurred abundantly in Stevia rebaudiana into grandiflorenic acid
基金Project supported by the National Natural Science Foundation of China （No. 21042007）, Nature Science Basic Research of Jiangsu Province for Higher Education （No. 10KJB 150016）, a Research Grant from the Innovation Project for Graduate Student of Jiangsu Province （CXlOB-O33Z）, Key Project in Science ＆ Technology Innovation Cultivation Program of Soochow University, and Innovation Project for Undergraduate Student of So- ochow University.
文摘Nucleophilic substitution of ferrocenyl alcohols with various aliphatic alcohols in the presence of a catalytic amount of ytterbium triflate [Yb（OTf）3] was studied. It was found the unsymmetrical ferrocenyl ethers could be easily obtained in excellent yields when the reactions were performed in primary and secondary alcohols. However, in other organic non-alcoholic solvents such as acetonitrile, the formation of symmetrical ferrocenyl ethers rather than unsymmetrical ones was observed.
基金supported by the National Key R&D Program of China(2022YFA1506000)the National Natural Science Foundation of China(22105110,22109110,22206094)+5 种基金the Natural Science Foundation of Shandong Province(ZR2021QB162,ZR2023YQ014)the Youth Innovation Team Project of Shandong Provincial Education Department(022KJ143)the Taishan Scholar Youth Expert Program in Shandong Province(tsqn202211122)the Gusu Innovation and Entrepreneurship Leading Talents Program(ZXL2022497)the Jiangsu Distinguished Professor Programthe Natural Science Foundation of Jiangsu Province(BK20210698)。
文摘The solvolysis of ammonia borane(AB)and the hydrogenation of nitroarenes represent significant reactions for hydrogen generation and value-added chemical synthesis.The strategic engineering of the catalysts is imperative for surmounting obstacles associated with their stability and catalytic efficiency.In this work,subnanometric bimetallic Pt–Pd clusters were encapsulated within silicalite-1(S-1)zeolites through a ligand-protected in-situ hydrothermal synthesis method.The synergetic effect of bimetallic composition and zeolite confinement markedly enhances the catalytic performance of representative Pt_(0.5)Pd_(0.5)@S-1-H catalyst,affording exceptional turnover frequency(TOF)values of 1,043 and 573 mol_(H_(2))mol_(metal)^(-1)min^(-1)for AB hydrolysis and methanolysis at ambient conditions,respectively,surpassing most of the state-of-the-art Pt-based catalysts.Kinetic and isotopic experiments reveal that the bimetallic catalytic system remarkably boosts the O-H cleavage of water,thereby facilitating the H_(2) production from AB hydrolysis.Remarkably,a conspicuous synergistic effect is demonstrated in the shape-selective tandem hydrogenation of nitroarenes,with the bimetallic catalyst facilitating both AB hydrolysis and nitroarene hydrogenation,giving a high TOF value of 1,260 h^(-1)under atmospheric pressure.This study not only demonstrates the effectiveness of bimetallic nanocatalysts encapsulated in zeolites for hydrogen production from chemical hydrogen storage materials,but also paves the way for the design of catalysts with multifunctional active sites capable of synergistically promoting tandem catalytic processes.
