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Abstract

N,N′-dichloro-bis[2,4,6-trichlorophenyl]urea, known as CC2, is used as a reactive chemical decontaminant of mustard agents. The present study was undertaken to establish the compatibility of CC2 with a number of commonly used suspending agents, using thermoanalytical techniques viz., thermogravimetry (TG) and differential scanning calorimetry (DSC) with the support of Fourier transform infrared spectroscopy (FTIR). The results demonstrated the applicability of TG and DSC as a fast screening tool for analysing the compatibility of drug with excipients at the early stages of a preformulation process. Methylcellulose, hydroxypropylcellulose, and betaine were found to be compatible with CC2.

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Abstract  

Flash pyrolysis of fentanyl and its analogues has been studied on pyrolysis-gas chromatograph-mass spectrometer (Py-GC-MS) system. Initial pyrolytic fragmentation of these compounds led to the formation of N-substituted-1,2,5,6-tetrahydropyridine and N-phenylpropanamide as the primary pyrolytic products. Moreover, depending up on the furnace temperature, these pyrolytic products can also undergo further fragmentation to give different compounds. We, herein, discuss the probable fragmentation routes of parent as well as pyrolytic products. This study will be useful while developing technologies for thermal aerosol generation of fentanyl and related compounds.

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Abstract

Thermal decomposition of neat TBP, acid-solvates (TBP·1.1HNO3, TBP·2.4HNO3) (prepared by equilibrating neat TBP with 8 and 15.6 M nitric acid) with and without the presence of additives such as uranyl nitrate, sodium nitrate and sodium nitrite, mixtures of neat TBP and nitric acid of different acidities, 1.1 M TBP solutions in diluents such as n-dodecane (n-DD), n-octane and isooctane has been studied using an adiabatic calorimeter. Enthalpy change and the activation energy for the decomposition reaction derived from the calorimetric data wherever possible are reported in this article. Neat TBP was found to be stable up to 255 °C, whereas the acid-solvates TBP·1.1HNO3 and TBP·2.4HNO3 decomposed at 120 and 111 °C, respectively, with a decomposition enthalpy of −495.8 ± 10.9 and −1115.5 ± 8.2 kJ mol−1 of TBP. Activation energy and pre exponential factor derived from the calorimetric data for the decomposition of these acid-solvates were found be 108.8 ± 3.7, 103.5 ± 1.4 kJ mol−1 of TBP and 6.1 × 1010 and 5.6 × 109 S−1, respectively. The thermochemical parameters such as, the onset temperature, enthalpy of decomposition, activation energy and the pre-exponential factor were found to strongly depend on acid-solvate stoichiometry. Heat capacity (C p ), of neat TBP and the acid-solvates (TBP·1.1HNO3 and TBP·2.4HNO3) were measured at constant pressure using heat flux type differential scanning calorimeter (DSC) in the temperature range 32–67 °C. The values obtained at 32 °C for neat TBP, acid-solvates TBP·1.1HNO3 and TBP·2.4HNO3 are 1.8, 1.76 and 1.63 J g−1 K−1, respectively. C p of neat TBP, 1.82 J g−1 K−1, was also measured at 27 °C using ‘hot disk’ method and was found to agree well with the values obtained by DSC method.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
B. Shivashankar
,
H. Naik
,
S. Suryanarayana
,
P. Prajapati
,
V. Mulik
,
K. Jagadeesan
,
S. Thakare
,
A. Goswami
, and
S. Ganesan

Abstract  

The reaction cross-sections for 64Ni(n, γ) 65Ni at E n  = 0.025 eV and 58Ni (n, p) 58Co at E n  = 3.7 MeV have been experimentally determined using activation and off-line γ-ray spectrometric technique. The thermal neutron flux used is from the thermal Column of the reactor APSARA at BARC, Mumbai, whereas the neutron energy of 3.7 MeV is from the 7Li(p, n) reaction at Pelletron facility, TIFR, Mumbai. The 64Ni(n, γ) 65Ni and 58Ni(n, p) 58Co reactions cross-sections from present work are compared with the available literature data and found to be in good agreement. The 58Ni(n, p) 58Co reaction as a function of neutron energy is also calculated theoretically using TALYS computer code version 1.2 and found to be higher than the experimental data.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
H. Naik
,
S. Surayanarayana
,
V. Mulik
,
P. Prajapati
,
B. Shivashankar
,
K. Jagadeesan
,
S. Thakare
,
D. Raj
,
S. Sharma
,
P. Bhagwat
,
S. Dhole
,
S. Ganesan
,
V. Bhoraskar
, and
A. Goswami

Abstract  

The 238U(n, γ)239U reaction cross-section at average neutron energy of 3.7 ± 0.3 MeV from the 7Li(p, n)7Be reaction has been determined using activation and off-line γ-ray spectrometric technique. The 238U(n, γ)239U and 238U(n, 2n)237U reaction cross-sections at average neutron energy of 9.85 ± 0.38 MeV from the same 7Li(p, n)7Be reaction have been also determined using the above technique. The experimentally determined 238U(n, γ)239U and 238U(n, 2n)237U reaction cross-sections were compared with the evaluated data of ENDF/B-VII, JENDL-4.0, JEFF-3.1 and CENDL-3.1. The experimental values were found to be in general agreement with the evaluated value based on ENDF/B-VII, and JENDL-4.0 but not with the JEFF-3.1 and CENDL-3.1. The present data along with literature data in a wide range of neutron energies were interpreted in terms of competition between different reaction channels including fission. The 238U(n, γ)239U and 238U(n, 2n)237U reaction cross-sections were also calculated theoretically using the TALYS 1.2 computer code and were also found to be in agreement experimental data.

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