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1.
乳酸环丙沙星单扫描示波极谱法研究   总被引:3,自引:0,他引:3  
研究了乳酸环丙沙星的极谱伏安行为,在pH=8.3的0.02mol/L,NH4Cl-NH3.H2O底液中,乳酸环丙沙星能产生1个灵敏的还原峰,峰电位为-1.61V,其导数峰高与浓度在3.9×10^-8~1.8×10^-6mol/L和1.8×10^6~1.1×10^-5mol/L范围内呈现良好的线性关系,相关系数r=0.9997,检测下限为2.5×10^-8mol/L,用于乳酸环丙沙星注射液的测定,相  相似文献   

2.
毛细管气相色谱法测定炼厂气中单体烃组分的含量   总被引:1,自引:1,他引:1  
采用PLOT/Al2O3石英毛细管气相色谱柱和氢火焰离子化检测器,建立了炼厂气中单体烃组分含量测定的毛细管气相色谱法,当炼厂气中单体烃组分的含量大于或等于2.1%时,RSD≤0.95%,当炼厂气中单体烃组分的含量为0.5%-2.1%时,RSD为0.95%-10.0%,当炼厂气中单体烃组分的含量为0.2%-0.5%时,RSD为10.0%-25.0%,该方法对单体烃组分的测定结果与行业标准SH/T0230-92《液化石油气组成测定法》的测定结果基本一致。  相似文献   

3.
Pd(Ni)对铜基催化剂的调变及对顺酐选择性加氢产物的调控   总被引:6,自引:0,他引:6  
 考察了在Cu-Ti-Al-O催化剂中添加Pd(或Ni)对活性中心Cu的调变作用及对顺酐加氢产物的调控.结果表明,Cu-Ni-Ti-Al-O是优良的顺酐选择性加氢制γ-丁内酯(GBL)反应的催化剂,催化剂中Cu和Ni含量的改变会影响加氢深度.当Cu含量较Ni含量高时,可以得到第三步加氢产物1,4-丁二醇和四氢呋喃,在270℃下其选择性为17.3%;当Ni含量较Cu含量高时,GBL选择性可达到100%.添加微量的Pd后,可加速活性组分Cu的还原,使Cu的还原更加彻底,获得纳米尺寸更小和晶格畸变率更大的Cu0晶粒,使顺酐第三步加氢产物的选择性显著提高.使用Cu-Pd-Ti-Al-O(n(Pd)/n(Cu)=0.08%)催化剂,在240℃下顺酐转化率为100%,1,4-丁二醇与四氢呋喃选择性为38.5%.  相似文献   

4.
间接原子吸收法测定药物制剂中利血生的含量   总被引:8,自引:0,他引:8  
提出了利血生的间接原子吸收法,该法基于利血生在碱性介质中的分离-产物半胱氨酸在适当的PH条件下与铜离子生成灰色沉淀,通过测定上清液中铜的含量来间接测定利血生的含量,在法在10-100mg/L范围内呈良好的线性关系(r=0.9992),回收率为98.5%-101.6%。该法可成功地用于药物制剂中利血生的测定。  相似文献   

5.
Mg的添加对Mo/ZSM-5催化剂催化甲烷芳构化性能的影响   总被引:8,自引:1,他引:8  
 通过XRD,N2吸附和吡啶FT-IR等方法考察了Mg的添加对Mo/ZSM-5催化剂物化性质的影响.吡啶FT-IR结果表明,Mo-Mg/ZSM-5催化剂上Lewis酸中心与Br¨onsted酸中心的比值随着Mg添加量的增加而增大.在甲烷芳构化反应中,虽然催化剂上的积碳量随着Mg含量的增加而减少,但只有6%Mo-0.75%Mg/ZSM-5催化剂表现出比6%Mo/ZSM-5催化剂更好的稳定性,6%Mo-2%Mg/ZSM-5和6%Mo-3%Mg/ZSM-5两个催化剂的稳定性均比6%Mo/ZSM-5催化剂差.根据催化剂稳定性与酸性的关系提出,在有足够Br¨onsted酸中心存在的前提下,可以通过调变Lewis酸中心和Br¨onsted酸中心的比值来提高催化剂的稳定性.  相似文献   

6.
采用盐酸-硫酸对以Cr,Mo,V为主要合金元素的工具钢试样进行消化,用ICP-AES法同时测定试样中Cr,Mo,V的含量。方法简便,结果满意。方法的加标回收率为95.5%-103.2%,相对标准偏差(n=9)为1.61%-6.64%。  相似文献   

7.
研究了胶束体系中乳酸环丙沙星的铁敏化荧光性质.实验发现,在pH 5.56的HAc-NaAc介质中,溶液中的Fe(Ⅲ)能与乳酸环丙沙星和十二烷基硫酸钠(SDS)反应生成稳定的络合物从而增强乳酸环丙沙星分子的内源性荧光,使其荧光强度显著增强.据此,建立了Fe(Ⅲ)-乳酸环丙沙星-SDS三元体系荧光增强法测定微量乳酸环丙沙星的新方法.该体系在最大激发波长λex=365nm,最大发射波长λem=430 nm时,乳酸环丙沙星浓度在4.0×10-9~2.0×10-5 mol/L范围内与其荧光强度呈良好的线性关系.方法的检出限为:6.2×10-10 mol/L,相对标准偏差(RSD)为1.8%(c=2.0×10-7 mol/L,n=5).  相似文献   

8.
有机溶剂中微量水的荷移光谱法测定   总被引:11,自引:0,他引:11  
研究了氯冉酸与有机溶剂中水的反应,确定了反应条件,氯冉酸与水的络合物的最大吸收波长为530nm。在乙醇、甲醇,正丙醇,异丙醇、正丁醇,正庚醇,正己醇溶剂中,水的含量分别在0-5%(V/V)或0-8%(V/V)范围内呈线性关系,相关系数为0.998或0.999;该方法重现性好,灵敏度高,操作简单,用于测定乙醇中微量水的含量,与标准值相符;加入回收法测得甲醇中水的回收率分别为98%-103%,结果令人满意。  相似文献   

9.
断续流动-氢化物发生原子荧光法测定浓缩苹果汁中的砷   总被引:5,自引:0,他引:5  
用断续流动-氢化物发生原子荧光法测定了浓缩萍果汁中的砷含量。确定了仪器的最佳条件,探讨了酸介质,硫脲-抗坏血酸用量,硼氢化钾加入量对测定As的影响。在选定的操作条件下,砷的检限为0.43ng/mL,相对标准偏差为3.4%-6.3%,加标回收率为94.0%-101.5%本方法简便,快速,灵敏,准确,应用于浓缩苹果汁中As的测定,得到满意的结果。  相似文献   

10.
基于秋加耶夫(Chugaev)反应,采用分光光度法测定银杏叶中聚异戊烯醇化合物含量;以ZnCl2的CH3COOH溶液-CH3COCl(体积比10:1)为显色剂,通过在388nm处测定溶液的吸光度确定聚异戊烯醇化合物的含量;聚异戊烯醇化合物在0.103-2.060mg范围内与吸光度值有良好线性关系;方法的回收率为97%-103%,相对标准偏差(RSD)为5.7%;方法简便、快速。  相似文献   

11.
用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.  相似文献   

12.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

13.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

14.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).  相似文献   

15.
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.  相似文献   

16.
In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.  相似文献   

17.
The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.  相似文献   

18.
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.  相似文献   

19.
Zhanhui Yang  Shiyi Yang  Jiaxi Xu 《Tetrahedron》2017,73(23):3240-3248
Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.  相似文献   

20.
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