Based on the absorption property of a diazine that can be formed by reaction of glyoxal and 3-methyl-2-benzothiazolinone hydrazone(MBTH)in the Ultravioletvisible(UV-vis)spectral region,a HPLC method was developed for ...Based on the absorption property of a diazine that can be formed by reaction of glyoxal and 3-methyl-2-benzothiazolinone hydrazone(MBTH)in the Ultravioletvisible(UV-vis)spectral region,a HPLC method was developed for the determination of glyoxal in acetaldehyde solution.Glyoxal was derivatised from MBTH and the derivatives(diazine)were analyzed by HPLC for identification and quantification.The determination was performed on a ZORBAX Eclipse XDB-C18 column(4.6250 mm,5 mm)at 35℃ with an injection volume of 10 mL,using a mixture of acetonitrile-water solvent(99∶5,v∶v)as a mobile phase with a flow rate of 0.8 mL·min^(–1).The proper derivative reaction conditions were the temperature of 70℃,MBTH to carbonyl molar ratio of 12,and reaction time of 110 min.The glyoxal diazine was a yellow dye with a maximum molar absorptivity at 401 nm and its retention time was 5.2 min under optimal HPLC conditions.The standard curve for glyoxal had a strong linear relationship with a regression coefficient(R2=0.999)in the range of 0.002–0.020 g·L^(–1).The analysis of glyoxal in an oxidising solution gave accurate results with a relative standard deviation(RSD)value of 0.55%.The average relative recovery was 102%.This efficient HPLC technique is also proposed for detecting other dicarbonyl compounds besides glyoxal.展开更多
The effects of the synthetic condition of SAPO-11 molecular sieves on ethanol dehydration to ethylene were studied.Product-compositions,ethanol conversion,and selectivity to ethylene of synthesized and commercial SAPO...The effects of the synthetic condition of SAPO-11 molecular sieves on ethanol dehydration to ethylene were studied.Product-compositions,ethanol conversion,and selectivity to ethylene of synthesized and commercial SAPO-11 molecular sieves were compared.Results are as follows:the optimal synthetic conditions for SAPO-11 molecular sieves are adding pseudoboehmite before orthophoshporic,using di-npropylamine as the template,having a mass fraction of 40%colloidal silica as the silica source and the starting gel obtained,and running at 200℃ for 48 h.From the patterns of NH3-TPD,the amount of acid synthesized by SAPO-11 molecular sieves is less than that by commercial SAPO-11 molecular sieves,and has a stronger weak acid.Also,ethanol conversion and selectivity to ethylene reached 99%at 280℃ on synthesized SAPO-11,lower by 20℃ compared to commercial SAPO-11.For two SAPO-11 molecular sieves,the by-products in the gas phase are mainly ethane,propane,propene,isobutane,n-butane,propadiene,butylene and some higher hydrocarbons.The by-products in the liquid phase are ethyl ether and acetaldehyde.展开更多
基金Financial support by the China Petroleum and Chemical Corporation is gratefully acknowledged.
文摘Based on the absorption property of a diazine that can be formed by reaction of glyoxal and 3-methyl-2-benzothiazolinone hydrazone(MBTH)in the Ultravioletvisible(UV-vis)spectral region,a HPLC method was developed for the determination of glyoxal in acetaldehyde solution.Glyoxal was derivatised from MBTH and the derivatives(diazine)were analyzed by HPLC for identification and quantification.The determination was performed on a ZORBAX Eclipse XDB-C18 column(4.6250 mm,5 mm)at 35℃ with an injection volume of 10 mL,using a mixture of acetonitrile-water solvent(99∶5,v∶v)as a mobile phase with a flow rate of 0.8 mL·min^(–1).The proper derivative reaction conditions were the temperature of 70℃,MBTH to carbonyl molar ratio of 12,and reaction time of 110 min.The glyoxal diazine was a yellow dye with a maximum molar absorptivity at 401 nm and its retention time was 5.2 min under optimal HPLC conditions.The standard curve for glyoxal had a strong linear relationship with a regression coefficient(R2=0.999)in the range of 0.002–0.020 g·L^(–1).The analysis of glyoxal in an oxidising solution gave accurate results with a relative standard deviation(RSD)value of 0.55%.The average relative recovery was 102%.This efficient HPLC technique is also proposed for detecting other dicarbonyl compounds besides glyoxal.
基金This work was financially supported by the National High Technology Research and Development Program of China(No.2006AA020101).
文摘The effects of the synthetic condition of SAPO-11 molecular sieves on ethanol dehydration to ethylene were studied.Product-compositions,ethanol conversion,and selectivity to ethylene of synthesized and commercial SAPO-11 molecular sieves were compared.Results are as follows:the optimal synthetic conditions for SAPO-11 molecular sieves are adding pseudoboehmite before orthophoshporic,using di-npropylamine as the template,having a mass fraction of 40%colloidal silica as the silica source and the starting gel obtained,and running at 200℃ for 48 h.From the patterns of NH3-TPD,the amount of acid synthesized by SAPO-11 molecular sieves is less than that by commercial SAPO-11 molecular sieves,and has a stronger weak acid.Also,ethanol conversion and selectivity to ethylene reached 99%at 280℃ on synthesized SAPO-11,lower by 20℃ compared to commercial SAPO-11.For two SAPO-11 molecular sieves,the by-products in the gas phase are mainly ethane,propane,propene,isobutane,n-butane,propadiene,butylene and some higher hydrocarbons.The by-products in the liquid phase are ethyl ether and acetaldehyde.
