A study of the mechanism of radiation‐induced polymerization of carbon suboxide

Abstract

The γ radiolysis of solid C3O2 at 77 K produces paramagnetic centers of several types. The ESR spectrum constitutes a number of narrow lines with an anisotropic g factor. Some of the centers are photounstable and are lost after optical bleaching. Heating the sample results initially in the loss of photounstable centers and then, in the temperature region in which solid C3O2 undergoes a phase transition (140 K), loss of the centers responsible for the center section of the ESR spectrum. In the temperature region 140–270 K concentration of the centers remained at the level of 1015−1016 g−1. At higher temperatures an intense polymerization of liquid C3O2 followed by a sharp increase in concentration of the paramagnetic centers was observed. It is assumed that in radiolysis at 77 K and on subsequent heating the formation of oligomeric centers in solid C3O2 results in a decreasing probability of their loss. Using a calorimetric technique, we studied the kinetics of the postradiation polymerization of C3O2. Small additions of acetone (cationic inhibitor) brought about the loss of the oligomeric centers and suppressed completely all postpolymerization. The polymerization rate increased with the concentration of the resulting polymer. An autocatalytic character of the process is supposed to be connected with the formation of polymer‐monomer complexes.

Spin-Forbidden Carbon–Carbon Bond Formation in Vibrationally Excited α-CO

“… 17 Like CO, C 3 O 2 is a fundamentally stable, closed-shell molecule; unlike CO, it is much more reactive, and could provide a carbon source for producing more complex organic molecules. 18 , 19 …”

The aqueous extract of Asparagus officinalis L. by-product exerts hypoglycaemic activity in streptozotocin-induced diabetic rats

“…The polymer (C 3 O 2 ) x can be obtained by chemical vapor deposition from the gas‐phase,7–10 via gamma‐ray initiation from the solid11, 12 or by using different means of initiating the polymerization reaction from liquid phase 12–14. The polymerization occurs even without adding a starting agent.…”

“…Various analytical methods have been used so far to obtain structural information about the amorphous polymer, for example, IR, UV/Vis,7–10, 13, 14 X‐ray diffraction8 molar mass determination,12 pyrolysis,9, 10, 12 titration of acidic groups, EPR spectroscopy7, 11, 13 and chemical analysis to determine the composition of the polymer. IR spectroscopy allowed the identification of some basic building units, for example carbonyl functions, ethenyl and ketene units, without being able to quantify their proportions.…”

The Structure of Poly(carbonsuboxide) on the Atomic Scale: A Solid‐State NMR Study

“…The highest yields have been achieved via thermolysis of the malonic acid bistrimethylsilylester on P 4 O 10 at 160 8C. [6] The polymer (C 3 O 2 ) x can be obtained by chemical vapor deposition from the gas-phase, [7][8][9][10] via gamma-ray initiation from the solid [11,12] or by using different means of initiating the polymerization reaction from liquid phase. [12][13][14] The polymerization occurs even without adding a starting agent.…”

“…In patent literature even claims of cyclopoly(carbonsuboxide)s are made. [19] Various analytical methods have been used so far to obtain structural information about the amorphous polymer, for example, IR, UV/Vis, [7-10, 13, 14] X-ray diffraction [8] molar mass determination, [12] pyrolysis, [9,10,12] titration of acidic groups, EPR spectroscopy [7,11,13] and chemical analysis to determine the composition of the polymer. IR spectroscopy allowed the identification of some basic building units, for example carbonyl functions, ethenyl and ketene units, without being able to quantify their proportions.…”