5676-67-5

Upstream product

• 108-43-0 3-monochlorophenol 
• 503-38-8 trichloromethyl chloroformate 
• 5070-13-3 bis-(p-nitrophenyl) carbonate 
• 75-44-5 phosgene 

Relevant academic research and scientific papers

Kinetic study of the phenolysis of bis(4-nitrophenyl) carbonate, bis(4-nitrophenyl) thionocarbonate, and methyl 4-nitrophenyl thionocarbonate

The reactions of a homogeneous series of phenols with bis(4-nitrophenyl) carbonate (BNPC), bis-(4-nitrophenyl) thionocarbonate (BNPTOC), and methyl 4-nitrophenyl thionocarbonate (MNPTOC) are subjected to a kinetic investigation in water, at 25.0 °C and ionic strength of 0.2 M (KCl). Under excess of phenol over the substrate, all the reactions obey pseudo-first-order kinetics and are first order in phenoxide anion. The reactions of BNPC show a linear Broensted-type plot with slope β=0.66, consistent with a concerted mechanism (one step). In contrast, those of BNPTOC and MNPTOC show biphasic Broensted-type plots with slopes β=0.30 and 0.44, respectively, at high pKa, and β=1.25 and 1.60, respectively, at low pKa, consistent with stepwise mechanisms. For the reactions of both thionocarbonates, the pKa value at the center of the BrSnsted plot (pKa0) is 7.1, which corresponds to the pKa of 4-nitrophenol. This confirms that the phenolyses of the thionocarbonates are stepwise processes, with the formation of an anionic tetrahedral intermediate. By the comparison of the kinetics and mechanisms of the title reactions with similar reactions, the following conclusions can be drawn: (i) Substitution of S- by O- in an anionic tetrahedral intermediate (T-) destabilizes it. (ii) The change of MeO by 4-nitrophenoxy in T- results in an increase of both the rate constant and equilibrium constant, for the formation ofT-, and also in an enlargement of the rate coefficient for the expulsion of 4-nitrophenoxide from T-. (iii) Substitution of an amino group in a tetrahedral intermediate by ArO destabilizes it. (iv) Secondary alicyclic amines and other amines show greater reactivity toward MNPTOC than isobasic phenoxide anions.

Synthesis of ring-substituted phenyl hydrazinecarboxylates and study of their protonation in dimethyl sulfoxide solutions

The pKa values of nineteen phenyl hydrazinecarboxylate hydrochlorides R-C6H4OCONHNH2.HCl (R = H, 3-and 4-Cl, 3-and 4-O2N, 4-Me) and their 1-methyl or 2-methyl derivatives were determined by potentiometric titration with tetrabutylammonium hydroxide in DMSO. IR spectra of the hydrazinecarboxylates and their hydrochlorides revealed that the hydrazinecarboxylate protonation occurs at N2. The methods of synthesis of phenyl hydrazinecarboxylate and their N-methyl derivatives were optimized.

Thermolysis of phenoxyaluminum compounds and formation of PCDD/F and their precursors

Within the study of the formation of chlorinated dioxins and dibenzofurans and their precursors the thermolysis of hexachloroethane over the aluminum melt was investigated. "De novo" synthesis of precursors of PCDD/F was studied in the model system AlCl3/elemental carbon. Totally chlorinated heterocyclic compounds have been detected parallel with the formation of organochlorine compounds. The possibility of inserting oxygen to aluminum organyls was presented. In order to gain more detailed knowledge of the catalytic behaviour of fly ash the chemistry of thermolysis of phenoxy- and chlorophenoxy aluminum compounds at 300°C with the presence and absence of Al2O3 was investigated. Reagent compounds and products of thermolysis were followed by mass spectrometry.