Under the conditions of tetramethyl ammonia chloride (TMAC) used as starting material, Ti-based Dimensionally Stable Anode (DSA), stainless steel used as cathode and Nafion 900 cation membrane as cell diaphragm, this ...Under the conditions of tetramethyl ammonia chloride (TMAC) used as starting material, Ti-based Dimensionally Stable Anode (DSA), stainless steel used as cathode and Nafion 900 cation membrane as cell diaphragm, this paper studies the synthesis of tetramethyl ammonium hydroxide (TMAH) by cell diaphragm electrolytic method, examining not only the effects of current density, concentration of starting material and cell temperature, on the product purity and current efficiency, but also the effects of electrolyte circulation rate on the service life of Ti-based DSA. The experiment puts forward an optimum processing condition, and experimental findings show that preparing TMAH by using this technique can obtain a current efficiency 74.7% and get product with a purity greater than 99.9%.展开更多
使用四甲基氢氧化铵(TMAH)液相改性聚偏氟乙烯(PVDF),以过氧化苯甲酰(BPO)为引发剂,一步将磺酸基甲基丙烯酸甲酯(SBMA)接枝到改性的PVDF上,制备了聚偏氟乙烯接枝聚磺酸基甲基丙烯酸甲酯(PVDFg-PSBMA)质子交换膜.利用傅里叶变换红外(FTIR...使用四甲基氢氧化铵(TMAH)液相改性聚偏氟乙烯(PVDF),以过氧化苯甲酰(BPO)为引发剂,一步将磺酸基甲基丙烯酸甲酯(SBMA)接枝到改性的PVDF上,制备了聚偏氟乙烯接枝聚磺酸基甲基丙烯酸甲酯(PVDFg-PSBMA)质子交换膜.利用傅里叶变换红外(FTIR)光谱和扫描电镜-X射线能谱(SEM-EDX)分析了膜的结构、形貌及硫元素分布情况.同时研究了不同质量分数的TMAH甲醇溶液对PVDF-g-PSBMA膜电导率和甲醇渗透率的影响.结果表明,TMAH使PVDF脱去HF产生碳碳双键且SBMA成功接枝到改性的PVDF骨架上,硫元素在膜内外分布均匀;PVDF-g-PSBMA膜的电导率和甲醇渗透率随TMAH在甲醇中质量分数的增多而增大,TMAH质量分数为20%的膜的质子电导率在20°C下达到0.0892 S cm–1,常温下的甲醇渗透率为4.04×10–7cm2 s–1;热重分析(TGA)表明,膜的热稳定性良好,耐热温度高达270°C.该膜作为电解质材料的直接甲醇燃料电池(DMFC)的最大功率密度达到17.06·m W cm–2.展开更多
Lead titanate nanostructures with different phases and morphologies, layered hexagonal PbTiO2（CO3）0.3- （NO3）0.35（OH） nanosheets, pyrochlore Pb2Ti2O6 nanodendites, pre-perovskite PbTiO3 nanofibres and perovskite ...Lead titanate nanostructures with different phases and morphologies, layered hexagonal PbTiO2（CO3）0.3- （NO3）0.35（OH） nanosheets, pyrochlore Pb2Ti2O6 nanodendites, pre-perovskite PbTiO3 nanofibres and perovskite PbTiO3 nanoplates, have been synthesized via a conventional hydrothermal route assisted with different concentra- tions of tetramethylammonium hydroxide （TMAH）. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and high-resolution TEM （HRTEM） were employed to characterize the phase, morphology and growth behavior of the synthesized samples. The results reveal that at low TMAH concen- tration the obtained samples are mainly of PbTiO2（CO3）o.3（NO3）0.35（OH） nanosheets. With the TMAH concentration increasing, the obtained samples change to pyrochlore Pb2Ti2O6 nanodendites, pre-perovskite PbTiO3 nanofibres and perovskite PbTiO3 nanoplates in turn. With the basis of the experimental results, the phase- and morpholo- gy-evolution mechanism of the lead titanate nanostructures is discussed by combining the analysis of the lattice structure feature and the properties of TMAH.展开更多
Tetramethylammonium methyl carbonate(TMAMC)was synthesized by using trimethylamine and dimethyl carbonate as starting materials and methanol as solvent.And then,TMAMC was hydrolyzed to tetramethylammonium hydrogen car...Tetramethylammonium methyl carbonate(TMAMC)was synthesized by using trimethylamine and dimethyl carbonate as starting materials and methanol as solvent.And then,TMAMC was hydrolyzed to tetramethylammonium hydrogen carbonate(TMAHC).TMAHC was a kind of internediate of tetramethylammonium hydroxide(TMAH),which was widely used in industrial catalysis and electronic industry.In the synthesis of TMAMC,reaction temperature,materials molar ratio and initial nitrogen pressure were investigated.The optimum reaction conditions was listed as follows:reaction temperature was 120℃,trimethylamine and dimethyl carbonate molar ratio was 1.1∶1,initial nitrogen pressure was 0.1MPa.On this conditions the yield of TMAMC reached 98.4%.In the hydrolysis of TMAMC,the best reaction temperature was 70℃,and the related reaction time was 40 minutes.展开更多
文摘Under the conditions of tetramethyl ammonia chloride (TMAC) used as starting material, Ti-based Dimensionally Stable Anode (DSA), stainless steel used as cathode and Nafion 900 cation membrane as cell diaphragm, this paper studies the synthesis of tetramethyl ammonium hydroxide (TMAH) by cell diaphragm electrolytic method, examining not only the effects of current density, concentration of starting material and cell temperature, on the product purity and current efficiency, but also the effects of electrolyte circulation rate on the service life of Ti-based DSA. The experiment puts forward an optimum processing condition, and experimental findings show that preparing TMAH by using this technique can obtain a current efficiency 74.7% and get product with a purity greater than 99.9%.
文摘使用四甲基氢氧化铵(TMAH)液相改性聚偏氟乙烯(PVDF),以过氧化苯甲酰(BPO)为引发剂,一步将磺酸基甲基丙烯酸甲酯(SBMA)接枝到改性的PVDF上,制备了聚偏氟乙烯接枝聚磺酸基甲基丙烯酸甲酯(PVDFg-PSBMA)质子交换膜.利用傅里叶变换红外(FTIR)光谱和扫描电镜-X射线能谱(SEM-EDX)分析了膜的结构、形貌及硫元素分布情况.同时研究了不同质量分数的TMAH甲醇溶液对PVDF-g-PSBMA膜电导率和甲醇渗透率的影响.结果表明,TMAH使PVDF脱去HF产生碳碳双键且SBMA成功接枝到改性的PVDF骨架上,硫元素在膜内外分布均匀;PVDF-g-PSBMA膜的电导率和甲醇渗透率随TMAH在甲醇中质量分数的增多而增大,TMAH质量分数为20%的膜的质子电导率在20°C下达到0.0892 S cm–1,常温下的甲醇渗透率为4.04×10–7cm2 s–1;热重分析(TGA)表明,膜的热稳定性良好,耐热温度高达270°C.该膜作为电解质材料的直接甲醇燃料电池(DMFC)的最大功率密度达到17.06·m W cm–2.
基金This work is supported by the National Natural Sci- ence Foundation of China （Nos. 61274004, 51232006） and the Zhejiang Natural Science Foundation of China （No. LY 12B07007）.
文摘Lead titanate nanostructures with different phases and morphologies, layered hexagonal PbTiO2（CO3）0.3- （NO3）0.35（OH） nanosheets, pyrochlore Pb2Ti2O6 nanodendites, pre-perovskite PbTiO3 nanofibres and perovskite PbTiO3 nanoplates, have been synthesized via a conventional hydrothermal route assisted with different concentra- tions of tetramethylammonium hydroxide （TMAH）. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and high-resolution TEM （HRTEM） were employed to characterize the phase, morphology and growth behavior of the synthesized samples. The results reveal that at low TMAH concen- tration the obtained samples are mainly of PbTiO2（CO3）o.3（NO3）0.35（OH） nanosheets. With the TMAH concentration increasing, the obtained samples change to pyrochlore Pb2Ti2O6 nanodendites, pre-perovskite PbTiO3 nanofibres and perovskite PbTiO3 nanoplates in turn. With the basis of the experimental results, the phase- and morpholo- gy-evolution mechanism of the lead titanate nanostructures is discussed by combining the analysis of the lattice structure feature and the properties of TMAH.
文摘Tetramethylammonium methyl carbonate(TMAMC)was synthesized by using trimethylamine and dimethyl carbonate as starting materials and methanol as solvent.And then,TMAMC was hydrolyzed to tetramethylammonium hydrogen carbonate(TMAHC).TMAHC was a kind of internediate of tetramethylammonium hydroxide(TMAH),which was widely used in industrial catalysis and electronic industry.In the synthesis of TMAMC,reaction temperature,materials molar ratio and initial nitrogen pressure were investigated.The optimum reaction conditions was listed as follows:reaction temperature was 120℃,trimethylamine and dimethyl carbonate molar ratio was 1.1∶1,initial nitrogen pressure was 0.1MPa.On this conditions the yield of TMAMC reached 98.4%.In the hydrolysis of TMAMC,the best reaction temperature was 70℃,and the related reaction time was 40 minutes.
