51095-15-9Relevant academic research and scientific papers
Product Distributions of the C2H2 + O and HCCO + H Reactions. Rate Constant of CH2(X3B1) + H
Boullart, Werner,Peeters, Jozef
, p. 9810 - 9816 (2007/10/02)
The branching ratios of the two dominant methylene sources in C2H2/O/H systems C2H2 + O -> CH2(3B1) + CO (r2a) or HCCO + H (r2b) and HCCO + H -> CH2(1A1) + CO (r3a) or CH2(3B1) + CO (r3b) have been determined, at 285 K, using discharge-flow/molecular beam mass spectrometry techniques (D-F/MBMS).The ratios were derived from the observed decrease of MBMS CH2 signals upon substituting 25percent of the helium bath gas by 0.5 Torr of methane, which selectively scavenges CH2(1A1); in the absence of CH4 the singlet CH2 is mainly collisionally converted to CH2(3B1).In this way, the ratios of the total formation rates of singlet and triplet CH2 are obtained.As the rate of reaction r3 is linked to the rate of reaction r2b by the known fraction of HCCO reacting with H, in competition with O, both the ratios k2a/k2b and k3a/k3b can be extracted from the data.Thus, including also probably systematic errors, the HCCO yield of C2H2 + O is found to be k2b/k2 = 85 +4-9 percent and the CH2(1A1) yield of HCCO + H, k3a/k3 = 92 +/- 15percent (95percent confidence intervals).In addition, the rate constant of CH2(3B1) + H -> CH(2Π) + H2 (r1) was derived relative to the known K(3CH2+O) from CH2 signals at different / ratios; k1 = (1.6 +/- 0.6) * 1014 cm3 mol-1 s-1.
The Ketyl Radical in the Oxidation of Ethyne by Atomic Oxygen at 300-600 K
Vinckier, C.,Schaekers, M.,Peeters, J.
, p. 508 - 512 (2007/10/02)
The reaction of ethyne with atomic oxygen was investigated in the temperature range 300-600 K, at a pressure of 2 torr.With molecular beam mass spectrometry, both methylene and ketyl radical were shown to be important primary products.An absolute measurement was made of the rate constant of reaction 7 of HCCO with O at T = 535 K: k7 = (1.10 +/- 0.10) X 1014 cm3 mol-1 s-1.The activation energy E7 was found to be E7 = 0.6 +/- 0.3 kcal mol-1.Reaction 2 of HCCO with H atoms is even faster; in Stern-Volmer experiments the ratio k2/k7 was determined to be 1.4 +/- 0.4 at T = 535 K and 1.3 +/- 0.2 at T = 285 K.
MECHANISM OF THE HCO* CHEMILUMINESCENCE IN HYDROCARBON-ATOM FLAMES.
Becker,Heinemeyer,Horie
, p. 898 - 903 (2007/10/02)
The mechanism of formation of the Vaidya-bands emitter HCO* in C//2H//2 plus O and C//3O//2 plus H plus O systems has been studied in the pressure range of 200-640 Pa at room temperature in a discharge-flow system connected to a photoionization mass spectrometer and a monochromator. HCO* chemiluminescence of comparable intensity is found in both the C//2H//2 plus O and the C//3O//2 plus O plus H system. A reaction has been proposed for the formation of electronically excited HCO* radicals. The reaction is consistent with the experimental results, and its exothermicity agrees with the HCO* excitation energy.
