基于重量法,以助溶剂TP溶解缩合磷酸铝,氯化-二氯双(乙二胺)合钴为沉淀剂,考察了样品加入量,溶解时间及沉淀反应时间对测定结果的影响。结果表明,取样1 g,溶解时间2 h,沉淀反应时间15 m in,测定结果的相对标准偏差RSD=0.39%,与热失重仪...基于重量法,以助溶剂TP溶解缩合磷酸铝,氯化-二氯双(乙二胺)合钴为沉淀剂,考察了样品加入量,溶解时间及沉淀反应时间对测定结果的影响。结果表明,取样1 g,溶解时间2 h,沉淀反应时间15 m in,测定结果的相对标准偏差RSD=0.39%,与热失重仪器分析法(含量测定)测定结果的相对误差为0.23%,该测定方法简捷,具有实用性。展开更多
A combination of X-ray powder diffraction, thermogravimetric analysis, diffuse reflection infrared Fourier transform, and ^31p magic-angle spinning nuclear magnetic resonance techniques with density function computati...A combination of X-ray powder diffraction, thermogravimetric analysis, diffuse reflection infrared Fourier transform, and ^31p magic-angle spinning nuclear magnetic resonance techniques with density function computation was used to elucidate the products and mecha- nism of the reactions among silica, H3PO4, and NaH2PO4 during the preparation of silica supported H3PO4 and NaH2PO4 catalysts. The spectral test results indicate that besides polyphosphoric acid, silicon phosphates on silica supported H3PO4 are also formed. On silica supported NaH2PO4 only sodium polyphosphates are present. Density functional theory （DFT） simulations indicate that in the initial stage, reaction of H3PO4 with silanol groups on the silica support is more favorable than that between H3PO4 itself. In contrast, dimerization and trimerization of NaH2PO4 are predicted to be the predominant initial reactions for the silica supported NaH2PO4 catalyst.展开更多
A novel environmental friendly catalyst, H3PW12O40/MCM-48, was prepared by impregnation method. The catalysts were characterized by means of XRD and FT-IR. The synthesis of butyraldehyde glycol acetal catalyzed by H3P...A novel environmental friendly catalyst, H3PW12O40/MCM-48, was prepared by impregnation method. The catalysts were characterized by means of XRD and FT-IR. The synthesis of butyraldehyde glycol acetal catalyzed by H3PW12O40/MCM-48 was studied with butyraldehyde and glycol as reactants. H3PW12O40/MCM-48 was an excellent catalyst for the synthesizing butyraldehyde glycol acetal and Keggin structure of H3PW12O40 kept unchanged after being impregnated on surface of the molecular sieve support. Effects of n（butyraldehyde）： n（glycol）, catalyst dosage, cyclohexane（water-stripped reagent） and reaction time on yields of the product were investigated. The optimum conditions had been found, that was, molar ratio of butyraldehyde to glycol was 1： 1.6, mass ratio of catalyst used to the reactants was 0.25% and reaction time was 75 min. Under these conditions, the yield of butyraldehyde glycol acetal can reach 79.74%.展开更多
A distinctive feature of phosphates is their special and significant ability to form inorganic polymeric compounds---condensed phosphates, which are destined to play a considerable role in our ＂high-tech＂ society in...A distinctive feature of phosphates is their special and significant ability to form inorganic polymeric compounds---condensed phosphates, which are destined to play a considerable role in our ＂high-tech＂ society in the future. Numerous olygophosphates, polyphosphates, double condensed phosphates and cyclophosphates with diverse formula, such as double tetra-, octa- and dodecaphosphates were obtained and described by us last years. The offered data are the outcomes of our scientific researches： of synthesis, analysis, and estimation of results in correlation with new achievements in inorganic polymer＇s chemistry. Many double condensed compounds, containing monovalent metals are obtained by us during systematic investigation of polycomponent systems, containing mono- and trivalent metals at temperature range 100-600 ~C. Synthesised condensed phosphates, in fact--inorganic polymers were examined in detail by chemical and thermogravimetric analysis, most compounds were examined by paper chromatography and the structures are determined by X-ray structural techniques/diffraction analysis. During our fundamental researches numerous new （about 70） unknown until now condensed phosphates have been obtained. Dependency of composition VS temperature and molar ratio, reliance of structure from duration of synthesis and radius of the ions are revealed.展开更多
文摘基于重量法,以助溶剂TP溶解缩合磷酸铝,氯化-二氯双(乙二胺)合钴为沉淀剂,考察了样品加入量,溶解时间及沉淀反应时间对测定结果的影响。结果表明,取样1 g,溶解时间2 h,沉淀反应时间15 m in,测定结果的相对标准偏差RSD=0.39%,与热失重仪器分析法(含量测定)测定结果的相对误差为0.23%,该测定方法简捷,具有实用性。
文摘A combination of X-ray powder diffraction, thermogravimetric analysis, diffuse reflection infrared Fourier transform, and ^31p magic-angle spinning nuclear magnetic resonance techniques with density function computation was used to elucidate the products and mecha- nism of the reactions among silica, H3PO4, and NaH2PO4 during the preparation of silica supported H3PO4 and NaH2PO4 catalysts. The spectral test results indicate that besides polyphosphoric acid, silicon phosphates on silica supported H3PO4 are also formed. On silica supported NaH2PO4 only sodium polyphosphates are present. Density functional theory （DFT） simulations indicate that in the initial stage, reaction of H3PO4 with silanol groups on the silica support is more favorable than that between H3PO4 itself. In contrast, dimerization and trimerization of NaH2PO4 are predicted to be the predominant initial reactions for the silica supported NaH2PO4 catalyst.
基金This work was financially supported by the Natural Science Foundation of Hubei Province, China （No. 2005ABA053）.
文摘A novel environmental friendly catalyst, H3PW12O40/MCM-48, was prepared by impregnation method. The catalysts were characterized by means of XRD and FT-IR. The synthesis of butyraldehyde glycol acetal catalyzed by H3PW12O40/MCM-48 was studied with butyraldehyde and glycol as reactants. H3PW12O40/MCM-48 was an excellent catalyst for the synthesizing butyraldehyde glycol acetal and Keggin structure of H3PW12O40 kept unchanged after being impregnated on surface of the molecular sieve support. Effects of n（butyraldehyde）： n（glycol）, catalyst dosage, cyclohexane（water-stripped reagent） and reaction time on yields of the product were investigated. The optimum conditions had been found, that was, molar ratio of butyraldehyde to glycol was 1： 1.6, mass ratio of catalyst used to the reactants was 0.25% and reaction time was 75 min. Under these conditions, the yield of butyraldehyde glycol acetal can reach 79.74%.
文摘A distinctive feature of phosphates is their special and significant ability to form inorganic polymeric compounds---condensed phosphates, which are destined to play a considerable role in our ＂high-tech＂ society in the future. Numerous olygophosphates, polyphosphates, double condensed phosphates and cyclophosphates with diverse formula, such as double tetra-, octa- and dodecaphosphates were obtained and described by us last years. The offered data are the outcomes of our scientific researches： of synthesis, analysis, and estimation of results in correlation with new achievements in inorganic polymer＇s chemistry. Many double condensed compounds, containing monovalent metals are obtained by us during systematic investigation of polycomponent systems, containing mono- and trivalent metals at temperature range 100-600 ~C. Synthesised condensed phosphates, in fact--inorganic polymers were examined in detail by chemical and thermogravimetric analysis, most compounds were examined by paper chromatography and the structures are determined by X-ray structural techniques/diffraction analysis. During our fundamental researches numerous new （about 70） unknown until now condensed phosphates have been obtained. Dependency of composition VS temperature and molar ratio, reliance of structure from duration of synthesis and radius of the ions are revealed.
