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91.
92.
《Analytical letters》2012,45(14):1189-1194
Abstract The paper describes a technique for quantitative determination of silicon in organic monomer and polymer materials based on low-temperature decomposition of samples in rf-discharge oxygen plasmas. The final step of analysis involves gravimetric determination of silicon in the form of silicon dioxide. The presence of fluorine (up to 50%) does not interfere with the determination of silicon. 相似文献
93.
Xiao-Feng Wu 《Tetrahedron letters》2012,53(45):6123-6126
A zinc-catalyzed oxidation of benzylic substrates has been developed. The corresponding carbonyl containing compounds have been produced in moderate to excellent yields. Both arenes and heteroarenes can be applied as substrates by using H2O2 as the oxidant. 相似文献
94.
《Analytical letters》2012,45(6):411-414
Abstract A Thermal Energy Analyzer has been interfaced to a high performance liquid chromatograph. The hplc-TEA system can be used for analysis of nanogram amounts of N-nitroso compounds. 相似文献
95.
96.
Pierrick Nun Violaine Pérez Monique Calmès Jean Martinez Frédéric Lamaty 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(12):3773-3779
The asymmetric alkylation of Schiff bases under basic conditions in a ball mill was performed. The starting Schiff bases of glycine were prepared beforehand by milling protected glycine hydrochloride and benzophenone imine, in the absence of solvent. The Schiff base was then reacted with a halogenated derivative in a ball mill in the presence of KOH. By adding a chiral ammonium salt derived from cinchonidine, the reaction proceeded asymmetrically under phase‐transfer catalysis conditions, giving excellent yields and enantiomeric excesses up to 75 %. Because an equimolar amount of starting material was used, purification was greatly simplified. 相似文献
97.
Ramin Ghahremanzadeh Mojtaba Mirhosseini Moghaddam Ayoob Bazgir Mohammad Mehdic Akhondi 《中国化学》2012,30(2):321-326
A four‐component reaction in the presence of Alum [KAl(SO4)2·12H2O] as an inexpensive and reusable catalyst using the ionic liquid as an effective green reaction media is reported. 相似文献
98.
99.
《Analytical letters》2012,45(3):215-221
Abstract An enzymatic method for estimating the age of biological specimens is described. The method is based on the slow racemization of L-aspartic acid to the D isomer. Conditions for protein extraction, enzymatic hydrolysis, pretreatment with stereospecific enzymes and assaying are discussed. The results obtained by this method are compared with the more conventional radiocarbon technique and its application to Holocene climatology is discussed. 相似文献
100.
《Journal of Coordination Chemistry》2012,65(24):4177-4187
Crystallization of an equimolar mixture of 1,10-dimethylphenanthroline (DMP) and manganese(II) chloride from N,N-dimethylformamide (DMF) has been studied. Rather than a useful route to a well-defined product, it was found that identical solutions could deposit crystals of three different compounds. The most common outcome was the formation of crystals of [MnCl2(dmp)(dmf)], 1, or co-crystallization of [MnCl2(dmp)(dmf)] and [{MnCl2(dmp)}2]. The co-crystals, 2, were always found to dissolve as crystals of 1 started to grow. Crystals of a third compound, [MnCl2(dmp)2], 3, were also isolated once. 相似文献