| || Nitration of Polystyrene Part II Effect of Nitrating Medium on Nitration
Author : Bajaj, I.;Kapoor, S.K.;Chatterjee, S.R.
Source : Defence Science Journal ; Vol:18(2) ; 1968 ; pp 89-94
Subject : 678 Composite Materials
Keywords : Anhydrous nitric;Sulphuric Acid;DMF;Nitroniumion
Abstract : Polystyrene has been nitrated in mixtures of anhydrous nitric and sulphuric acid (70 : 30 and 80 : 20 by volume). Degree of substitution of nitro group per benzene ring varies from 1 to 2 depending on the time, temperature and composition of the nitrating media. Effect of polar and non polar solvents on nitration has been studied by nitrating the polymer in (i) fuming nitric acid and (ii)mixture of nitric and sulphuric acid in presence of dimethyl formamide (DMF) and carbon tetrachloride (CCI/Sub4). MF increase the rate of nitration in fuming nitric acid whereas the rate of nitration is lowered in the presence of DMF in the nitrating mixtures. In the case of CCI/Sub4, however, the effect is just the opposite to that observed in DMF. The results have been explained from the mechanism of the formation of 'nitroniumion,NO/Sub2+ in various nitrating media. Degradation of the polymer has been found to be comparatively less in the presence of the organic solvents used in the study.
| || Synthesis and Characterisation of Addition Compounds of Pyridine Carboxylic Acid Hydrazides with Tin IV Halides, Organotin IV Halides and Thicyanates
Author : Rao, D.S.S. Vara Prasada ;Aggarwal, R.C.
Source : Defence Science Journal ; Vol:31(2) ; 1981 ; pp 167-172
Subject : 547 Organic Chemistry;54 Chemistry
Keywords : Di adducts ;Pyridine nitrogen;Terminal nitrogen;IR spectral studies;DMF
Abstract : Addition compounds of the compositions SnX/sub 4/.xL and R/sub n/SnX/sub 4-n/.xL where X=Cl/sup -/, Br/sup -/, I/sup -/, or (NCS)/sup -/, R=phenyl or n-butyl, L = picolinic acid hydrazide (PH), nicotinic acid hydrazide (NH) or isonicotinic acide hydrazide (INH), x=1 or 2 and n= 1,2 or 3 have been prepared and characterised with the help of elemental analysis, molar conductance, UV and IR spectral studies. All the adducts are nonionic as evidenced from their low molar conductances in DMF. UV and IR spectral studies show that NH and INH coordiante through carbonyl oxygen and terminal nitrogen; and (PH) through carbonyl oxygen and ring nitrogen in monoadducts. All the three isometric pyridine carboxylic acid hydrazides are coordinated through pyridine nitrogen alone in the di-adducts. Octahedral geometry has been proposed for mono-as well as di-adducts.