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51.
Wide-line PMR studies on solid p-toluidine have been made in the temperature range 77–318 K at 7.5 MHz. Analysis of second moment data suggests a rigid and non-rotating state of the crystal lattice at 77 K. The molecular and crystal structure is confirmed. The second moment gradually decreases up to 240 K (a fall of 2.8 G2) which is indicative of quantum mechanical tunnelling of methyl protons. An observed abrupt fall in p.s.m. beyond 240 K is followed by a phase transition and is attributed to methyl and amino group reorientation upto the melting point. The potential barrier to the reorientation is found to be approximately 8.88 kcal mol?1 in the solid phase. 相似文献
52.
Ila Sircar 《Journal of heterocyclic chemistry》1983,20(6):1473-1476
A method for the synthesis of 3,4-dichloro-6-phenylpyridazine 5 was described. The compound 5 was used as an intermediate for the synthesis of a series of 4-amino-6-phenyl-3(2H)-pyridazinones. 相似文献
53.
A reversed-phase gradient elution, UV detection method is developed for the simultaneous determination of mono (2-ethylhexyl) phthalate [MEHP] and di (2-ethylhexyl) phthalate [DEHP] in tissue samples. The method is validated with respect to extraction recovery, inter and intra-day precision, linearity of response, detect ability, and specificity. The validated method has been successfully applied to the study of DEHP and MEHP in liver, kidney, testis, brain, and plasma samples from rat. 相似文献
54.
A highly regioselective conversion of DHP
to DHP
has been achieved for the first time in high yield. Treatment of the bromide
with different nucleophiles under basic conditions produced 2-substituted 1,4-dihydropyridines in high yields and purity. 相似文献
55.
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58.
An attempt has been made to calculate the free energy values for possible reactions utilising the available thermodynamic data in order to study the sulfation of CuO, Fe2O3, MnO2 and NiO with (NH4SO4, and further trials have been made to determine the exact reaction through differential thermal analysis. There is no real correlation between the theoretical value of ΔH° and that calculated from the DTA peak, which may be due to some uncertainty in the thermodynamic values and the possibility of some side reactions. 相似文献
59.
Shivaji Sircar 《Adsorption》2006,12(3):167-174
An analytical mathematical model is used to investigate the effectiveness of forced convection for removal of the heat of
adsorption from an adsorbent mass undergoing a differential adsorption process in a flow system. An example of such a process
is measurement of gas adsorption kinetics using a differential adsorption bed. Isothermal operation may not be achieved even
when a high gas flow rate is used, particularly if the sorption kinetics is relatively fast. Very small changes in the adsorbent
temperature can cause significant departure from the isothermal uptake behavior when the heat of adsorption is moderately
large. A criterion for validity of isothermal data analysis is given. 相似文献
60.
Glucose, fructose, xylose, arabinose, and sucrose have been determined titrimetrically using manganese(III) sulfate as an oxidant. On reaction in the dark, glucose consumes 5, fructose 7, xylose and arabinose 6 each, and sucrose after hydrolysis 12 equivalents of Mn(III) per mole, respectively. Sucrose has also been estimated following other methods and the results have been compared. Two leaf sample extracts are analyzed for the determination of reducing sugar and total reducing matter and the results are compared with those obtained by the other method. 相似文献