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1.
利用金属交换法合成了四个新的含钌手性过渡金属簇合物[MRuCo(CO)_8(μ_3-Se)[η_5-C_5H_4C(O)R}]( 1 M= Mo, R= OEt; 2 M= W, R= OEt; 3 M= Mo, R= CH_2CH_2COOMe; 4 M= W, R= CH_2CH_2COOMe),并用红外、核磁、元素分析测试结果进行表征,对簇合物1进行了单晶结构测定,晶体属单斜晶系,P2_1/n空间群,晶胞参数a=10.168(2)A,b=9.018(2)A,c=23.121(3)A,β=92.50(1)°,Z=4。 相似文献
2.
甲醇催化氧化重整反应制氢的研究 总被引:14,自引:1,他引:13
研究了Cu/Zn/Al系列催化剂催化甲醇氧化重整反应制氢,得到活性,选择性及稳定性较好的催化剂Cu60Zn30Al5Ce5;并且考察了Cu60Zn30Al5Ce5为催化剂时,该反应的工艺条件如温度,物料配比等,当压力为0.1MPa,温度为240℃,CH3OH:H2O=1:0.8,CH3OH:O2=4:1时,甲醇的转化率达97.75%,在此反应条件下,反应100h后,甲醇的转化率仍在96%以上。 相似文献
3.
本在恒定特丁醇质量分数x=0.10的条件下,应用电动势测定了无液接界电池(A)和电池(B)的电动势:Pt,H2(1.013×10^5Pa)|HC(m),tert.-C4H9OH(x),H2O(1-x)|AgCl-Ag (A) Pt,H2(1.013×10^5Pa)|HCl(mA),NaCl(mB),tert.-C4HoOH,H2O(1-x)|AgCl-Ag (B)根据电池(A)电动势确定了 相似文献
4.
5-氨基水杨酸锌及相关物质的高效液相色谱分析研究 总被引:3,自引:0,他引:3
对5-氨基水杨酸锌及相关物质5-氨基水杨酸、水杨酸、对氨基苯酚和5-苯偶氮基水杨酸的高效液相色谱法(HPLC)的分离条件进行了优化研究,结果表明,采用CLC-ODS(150mm×6.0mmi.d.,10μm)作为分离柱,1%(V/V)HAc-MeOH(4∶6)作为流动相,在流速为1mL/min的情况下,上述5种物质在10min内可以达到基线分离,保留时间的日内和日间的变异系数分别小于2%和5%,在一定浓度范围内,浓度与峰面积的线性关系良好。 相似文献
5.
偶合反应化学发光法测定痕量银的研究 总被引:6,自引:0,他引:6
本将Ag(Ⅰ)催化S2O^2-8氧化Mn(Ⅱ)生成MnO^-4的催化反应与LuminolMnO^-4-OH^-的化学发光反应相偶合,建立起一种新的灵敏测定痕量银的化学发光分析法,在所研究的优化条件下,该法测定银的选择性较好,检测限达到3.2×10^-12g/mLAg线性浓度范围为1.0×10^-11-1.0×10^-5g/mLAg,用于水样分析,结果较为满意。 相似文献
6.
微乳液的增敏作用研究:Ni(Ⅱ)—5—Br—PADAP的分光光度法测定 总被引:5,自引:1,他引:5
以含水量80%的阴离了了型SDS/n-C5H11OH/n-C7H16/H2O微乳液为介质,进行了Ni(Ⅱ)-5-Br-PADAP分光光度研究,其表观摩尔吸光系数为1.13×10^5L.mol^-1.cm^-1,与相应含水量的SDS胶束介质比较,测定灵敏度显著提高,样品分析令人满意。 相似文献
7.
本文报道了一个灵敏度高,选择性好的测定痕量钍的新光度分析法。在聚乙烯醇存在下,钍钼杂多酸和丁基罗丹明B形成离子缔合物,其适宜条件为CHClO4=1.3MOL/L,CMoO^2-4=6.8×10^-4mol/L,CBRB=2.7×10^-5mol/L,PVA0.08%。 相似文献
8.
50℃下,测定了双十八烷基二甲基氯化铵(DODMAC)/n-C10H21OH/10%n-C10H22/H2O四元体系相图,确定了液晶区域范围,用^2H NMR方法,并辅以偏光显微镜照片,确定了液晶为反相六角状,用SAXS求出了液晶晶面间距,确定了晶面间距d1与含水量fw/(1-fw)之间的线性关系,并求得圆柱形聚集体的直径ds=4.035nm。 相似文献
9.
用微电子平面工艺制备了带宽和边长分别为10、20、30μm的带形和正方形微电极阵列(BMEA和SMEA)。在K3Fe(CN)6溶液中研究了它们的电化学特性。边长为10μm的SMEA(工作电极总面积仅为9×10^-3mm^2)有最大的电流密度(12.1μA/mm^2)和最短的响应时间(5s)。同一硅片中任选5个SMEA其H2O2工作曲线的线性范围为0.1~5mmol/L,平均斜率为220nA/mmo 相似文献
10.
用银和铅标记人白蛋白的离子选择电极电位法研究 总被引:1,自引:0,他引:1
用离子选择电极电位法研究了银和铅与人白蛋白(HSA)的配合平衡。明确证实银和铅都与HSA形成了单核配合物MA和MA2.Ag-HSA配合物的稳定性积β11=4.4×10^7,β12=1.0×10^12;Pb=HSA配合物的β11=3.1×10^5,β12=2.0×10^9。根据HS与人白蛋白羊抗血清(GAHA)的免疫反应,用银和铅分别标记HSA时,测定GAHA(效价1:40)的线性范围是0.2~2. 相似文献
11.
The degradation has been studied using thermogravimetry and thermal volatilization analysis; product analysis has been carried out by GLC and spectroscopy. The copolymers yield water and methanol below 300°; at higher temperatures, the products also include methyl methacrylate, carbon monoxide, carbon dioxide and methane. Quantitative comparison of the yields of methanol and methyl methacrylate has been made with predicted yields based upon sequence distribution calculations. Methanol is believed to result by two routes (i) intramolecular cyclization of adjacent ester and acid chain units at low temperatures, and (ii) fragmentation of ester units, in competition with depolymerization, at higher temperatures. Methyl methacrylate yields are substantially lower than the MMA content of the copolymer, as a result of these processes; some MMA units also appear in the product fraction volatile at degradation temperatures but not at ambient temperature. The partially-degraded copolymers develop anhydride ring structures in the chain as a result both of dehydration and of methanol production. The mechanisms of the various reactions are discussed. 相似文献
12.
Hitoshi Kubota Yukitaka Murata Yoshitaka Ogiwara 《Journal of polymer science. Part A, Polymer chemistry》1973,11(2):485-492
The effects of swelling of the sample and polymerization solvents were studied for photo-induced graft copolymerization of vinyl monomers on cellulose. The graft copolymerization of methyl methacrylate (MMA) was activated by swelling of the sample or organic solvent-water solutions within a certain range of their concentrations. Though each organic solvent gave a maximum in per cent grafting and the number of grafts at about 25 vol-% concentration, the initiation reaction scarcely took place at 100% concentration; thus, the solvent itself is considered to have a negative effect. The solvents used in the experiments were all hydrophilic, such as methanol, acetone, and dioxane. The average molecular weight of the grafted PMMA differed in each solvent, indicating a different characteristic effect of solvent on the growing grafted polymer radicals. The presence of ferric ion as a sensitizer stimulated further the contributions of the sample swelling and the organic solvents to the copolymerization reaction. A similar effect was observed for styrene as for MMA, but not for acrylic acid and methacrylic acid. 相似文献
13.
近年来,由于煤化工行业产能过剩,煤基气相法一步合成甲基丙烯酸甲酯(MMA)工艺引起了研究者们的兴趣,但反应温度高、产物收率和选择性低、催化剂易积碳失活以及甲醛易挥发和聚合一度成为该研究领域的瓶颈问题.本文通过构建温和、高效的钴配合物催化借氢阻断体系,解决了甲醇脱氢生成甲醛、丙酸甲酯与甲醛羟醛缩合生成MMA以及氧气阻断MMA加氢相串联的难题,从而实现了以丙酸甲酯和甲醇为原料,在80℃下液相法一步合成MMA的新工艺,产物收率和选择性分别为25.7%和92.6%.通过核磁共振表征和动力学同位素效应实验验证了钴配合物催化剂活化与甲醇脱氢机理,并确定甲醇的C–H键活化与断裂为速率控制步骤,为煤基合成MMA提供了新的研究方向. 相似文献
14.
Ion-pair reverse-phase HPLC-inductively coupled plasma (ICP) MS was employed to determine arsenite [As(III)], dimethyl arsenic acid (DMA), monomethyl arsenic (MMA) and arsenate [As(V)] in Chinese brake fern (Pteris vittata L.). The separation was performed on a reverse-phase C18 column (Haisil 100) by using a mobile phase containing 10 mM hexadecyltrimethyl ammonium bromide (CTAB) as ion-pairing reagent, 20 mM ammonium phosphate buffer and 2% methanol at pH 6.0. The detection limits of arsenic species with HPLC-ICP-MS were 0.5, 0.4, 0.3 and 1.8 ppb of arsenic for As(III), DMA, MMA, and As(V), respectively. MMA has been shown for the first time to experimentally convert to DMA in the Chinese brake fern, indicating that Chinese brake fern can convert MMA to DMA by methylation. 相似文献
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16.
液相色谱-双通道原子荧光检测联用法同时测定砷和硒的形态 总被引:6,自引:0,他引:6
建立了一种利用高效液相色谱-双通道原子荧光检测联用同时进行砷和硒形态分析的方法。以10 mmol/L NH4H2PO4溶液(pH 5.6)(添加2.5%(体积分数)的甲醇)为流动相,在12 min内同时分离了三价砷(As(III))、一甲基砷(MMA)、二甲基砷(DMA)、五价砷(As(V))、硒代胱氨酸(SeCys)、硒代蛋氨酸(SeMet)和四价硒[Se(IV)]等化合物。As(III)、DMA、MMA、As(V)、SeCys、SeMet和Se(IV)的检出限分别为1,3,2,3,4,18和3 μg/L (进样量为200 μL),5次测定的相对标准偏差为1.9%~6.1%(As 100 μg/L, Se 300 μg/L)。应用该方法对人体尿样及硒酵母片中砷和硒的形态进行了分析,目标物在尿样中的加标回收率为83%~108%,在硒酵母片中的加标回收率为88%~105%。实验结果表明,该方法可用于尿样及药品中砷和硒形态的日常分析。该方法减少了样品的分析时间和试剂用量,降低了工作强度,提高了工作效率。 相似文献
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Summary Because methylmalonic acid (MMA) accumulates in the body fluids of patients suffering from inherited metabolic disorders involving its pathway, the quantitation of this metabolite is not only fundamental to diagnosis but is also important in the follow-up of affected patients under treatment.We describe the method set up and used in our laboratory for the measurement of MMA in body fluids and propose its application to plasma as the reference method for the biochemical diagnosis and follow-up of methylmalonic acidaemias. 相似文献
19.
J. F. López-Sánchez M. B. Amram M. D. Lakkis F. Lagarde G. Rauret M. J. F. Leroy 《Fresenius' Journal of Analytical Chemistry》1994,348(12):810-814
Capillary zone electrophoresis has been used for the separation of arsenite, arsenate, monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and phenylarsonic acid. The separation was achieved using a fused silica capillary filled with a phosphate buffer. The on-column U.V. detector was operated at 190 nm. The influence of voltage and injected volume, reproducibility of calibration and recovery from a drinking water sample were studied. Using the calibration plot method and phenylarsonic acid as internal standard the mean recoveries for arsenate, MMA and DMA were 104%, 97% and 97% respectively. 相似文献
20.
Experimental yields of methanol and methyl methacrylate (MMA), produced in degradation to 500° of copolymers of MMA with lithium, sodium and potassium methacrylates (KMA) respectively, have been compared with the amounts expected on the basis of composition and sequence distribution. Rates of formation of these products under isothermal conditions have also been measured and activation energies for MMA formation at various compositions in the KMA-MMA copolymer series have been evaluated. The activation energy changes from 35 ± 5 kcal mole?1 in PMMA to 52 ± 5 kcal mole?1 in a 75 mole% KMA copolymer, indicating increasing difficulty in depolymerization to MMA as the MMA sequences become shorter. The primary route to methanol is by a cyclization involving adjacent ester and salt units in the chain, giving anhydride rings and metal methoxide as the initial products. Methanol yields and the positions of the maxima in the yield vs copolymer composition curves, however, are found to be inconsistent with those predicted from sequence distribution calculations. It is argued that water retained by the copolymers plays a key part in the reaction scheme by converting the metal methoxide to methanol and hydroxide; the latter then causes conversion of ester groups to salt units, so permitting further cyclization in copolymers initially rich in MMA. Mechanisms are discussed in detail. 相似文献