Liquid crystalline of a new carbosilane dendrimer of the second generation(D2) containing thirty-six 4-nitroazobenzene groups in its periphery was characterized by means of polarizing optical micrograph, DSC and WAXD....Liquid crystalline of a new carbosilane dendrimer of the second generation(D2) containing thirty-six 4-nitroazobenzene groups in its periphery was characterized by means of polarizing optical micrograph, DSC and WAXD. Mesogenic compound M5 exhibits threaded, schlieren and inversion lines texture of the nematic phase on the cooling from isotropic phase to solidified temperature. Dendrimer D2 shows the focal conic fan-shaped texture of the smectic A phase on the heating course from 69 to 187 ℃ and on the cooling course from 183 to 64 ℃. After cooling, the smectic E(S E) phase with a texture of the focal conic fan-shape with stripes and concentric arcs appears from smectic A(S A) phase. Phase behavior of dendrimer D2 in liquid crystalline state was K69S A187I182S A57S E47K. The isotropic-smectic A transition enthalpy, smectic A-smectic E transition enthalpy and isotropic-smectic A transition entropy were 1.8, 4.5 and 4.0 J/(K·mol), respectively, and were in agreement with or close to those of small molecular liquid crystal.展开更多
In the presence of Triton X100,the color reaction of Mercury(Ⅱ)with 2hydroxy5nitrophenyldiazoaminoazobenene(HNPDAAB)was studied.Mercury(Ⅱ)reacts with HNPDAAB and forms a 1∶1 red complex at pH=95-110 buffer solution...In the presence of Triton X100,the color reaction of Mercury(Ⅱ)with 2hydroxy5nitrophenyldiazoaminoazobenene(HNPDAAB)was studied.Mercury(Ⅱ)reacts with HNPDAAB and forms a 1∶1 red complex at pH=95-110 buffer solution of Na2B4O7NaOH.The molar absorptivity is 256×105L·mol-1·cm-1.Beer’s law is obeyed in the concentration range of 0～12μg/25mL for Mercury(Ⅱ).The results are in agreement with those determined by the conventional method.This new method was used to determine trace mercury in wastewater.展开更多
在室温下,以对氯邻硝基苯胺邻叔丁基对甲基苯酚和亚硝酸钠为原料通过固相重氮偶合反应一步合成了2-硝基-4-氯-2′-羟基-3′-特丁基-5′-甲基偶氮苯。反应时间15 m in,产率达93%。以HPLC分析,其纯度>99%,并用IR和UV光谱等对其结构进...在室温下,以对氯邻硝基苯胺邻叔丁基对甲基苯酚和亚硝酸钠为原料通过固相重氮偶合反应一步合成了2-硝基-4-氯-2′-羟基-3′-特丁基-5′-甲基偶氮苯。反应时间15 m in,产率达93%。以HPLC分析,其纯度>99%,并用IR和UV光谱等对其结构进行了表征和确认。展开更多
文摘Liquid crystalline of a new carbosilane dendrimer of the second generation(D2) containing thirty-six 4-nitroazobenzene groups in its periphery was characterized by means of polarizing optical micrograph, DSC and WAXD. Mesogenic compound M5 exhibits threaded, schlieren and inversion lines texture of the nematic phase on the cooling from isotropic phase to solidified temperature. Dendrimer D2 shows the focal conic fan-shaped texture of the smectic A phase on the heating course from 69 to 187 ℃ and on the cooling course from 183 to 64 ℃. After cooling, the smectic E(S E) phase with a texture of the focal conic fan-shape with stripes and concentric arcs appears from smectic A(S A) phase. Phase behavior of dendrimer D2 in liquid crystalline state was K69S A187I182S A57S E47K. The isotropic-smectic A transition enthalpy, smectic A-smectic E transition enthalpy and isotropic-smectic A transition entropy were 1.8, 4.5 and 4.0 J/(K·mol), respectively, and were in agreement with or close to those of small molecular liquid crystal.
文摘In the presence of Triton X100,the color reaction of Mercury(Ⅱ)with 2hydroxy5nitrophenyldiazoaminoazobenene(HNPDAAB)was studied.Mercury(Ⅱ)reacts with HNPDAAB and forms a 1∶1 red complex at pH=95-110 buffer solution of Na2B4O7NaOH.The molar absorptivity is 256×105L·mol-1·cm-1.Beer’s law is obeyed in the concentration range of 0～12μg/25mL for Mercury(Ⅱ).The results are in agreement with those determined by the conventional method.This new method was used to determine trace mercury in wastewater.
