Reactions between formaldehyde and nitrogen dioxide. Part I.—the kinetics of the slow reaction

Abstract

The non-explosive reaction between nitrogen dioxide and formaldehyde has been studied over a range of temperatures between 1 1 8 O C and 184" C. It has been shown that up t o 160' C the reaction is homogeneous and the rate proportional t o pHCHO , pNOI. The value of k is given by k = 1c7.le -159100/RT l./mole sec. The products of the reaction are mainly NO, CO, C 0 2 and H,O, with possibly some N, and N,O, but no hydrogen was observed among the gases. The ratio CO/CO, was practically constant throughout the course of the reaction. A possible mechanism is suggested t o account for the experimental results, and attention is drawn t o the low values of the B factor for other reactions involving Above 1 6 0 O C there appears t o be some change in mechanism, for which k is estimated to be 10@e -19*000/RT, and a t still higher temperatures the reaction becomes explosive. NO 2.I n studies of gas-phase oxidative reactions, nitrogen dioxide, as the main oxidizing agent, has received very little attention, though of course it is well known that the addition of small quantities of nitrogen dioxide has a marked effect on the kinetics of the oxidation of hydrogen, carbon dioxide, etc., by oxygen. Only two reactions involving oxidation by nitrogen dioxide have been reported in any detail, namely the oxidation of carbon monoxide 1 and sulphur dioxide 2 respectively.The oxidation of organic molecules by nitrogen dioxide is of particular interest in elucidating the mechanisms involved in the thermal decomposition of nitric esters.that the primary process in such decompositions is the breaking of the O-NO2 bond. The remaining alkoxy fragments give rise to alcohols and aldehyde^.^ These alcohols and aldehydes react with the nitrogen dioxide formed in the primary process to give oxides of carbon, and lower oxides of nitrogen.These papers deal with the slow and explosive oxidation of the simplest aldehyde, viz. formaldehyde by NO,. It has been suggested 3, 4 3 5, Experiment a1 Materia~s.-~ORMALDEHYDE.-~on0meric formaldehyde was prepared by NITROGEN DIOxIDE.-Liquid nitrogen tetroxide supplied by the I.C.I. Ltd.the method of Spence and Wild,s and stored a t liquid air temperature. was sublimed in vacuo, and stored a t -80" C.

Theoretical study of the reaction mechanism and kinetics of low-molecular-weight atmospheric aldehydes (C1–C4) with NO2

“…S3aed. For the reaction of formaldehyde with NO 2 , the rate constants are consistent with the experimental values obtained by Pollard and Wyatt, 1949 within the temperature range of 391e457 K and by Lin et al (1990) within the temperature range of 1143e1653 K, while are somewhat lower than the results measured by He et al (1989) within the temperature range of 393e476 K. For example, the fitted two-parameter expression from the CVT/SCT rate constants within 391e457 K is k ¼ 2.41 Â 10 À14 exp (e7812/T) cm 3 molecule À1 s À1 , in line with the experimental expression of k ¼ 2.16 Â 10 À14 exp (e7600/T) cm 3 molecule À1 s À1 (Pollard and Wyatt, 1949). As shown in Fig.…”

“…For formaldehyde, a linear Arrhenius plot with the rate constants within a temperature range of 393 to 476 K was reported by He et al (1989). The rate constants are higher than those of Pollard and Wyatt (1949) by a factor of 5. As for acetaldehyde, the rate constants measured by four experimental groups (Christie and Voisey, 1967;Davis and Corcoran, 1972;Mcdowell and Thomas, 1950;Pedler and Pollard, 1957) are not consistent well with each other.…”

“…The total CVT/SCT rate constants as well as the corresponding available experimental values (Christie and Voisey, 1967;Davis and Corcoran, 1972;He et al, 1989;Jaffe and Wan, 1974;Lin et al, 1990;Mcdowell and Thomas, 1950;Pedler and Pollard, 1957;Pollard and Wyatt, 1949) are plotted in Fig. S3aed.…”

“…In early literatures, considerable experimental investigations have been devoted to the kinetics of formaldehyde (He et al, 1989;Lin et al, 1990;Pollard and Wyatt, 1949) and acetaldehyde (Christie and Voisey, 1967;Davis and Corcoran, 1972;Mcdowell and Thomas, 1950;Pedler and Pollard, 1957) with NO 2 . For formaldehyde, a linear Arrhenius plot with the rate constants within a temperature range of 393 to 476 K was reported by He et al (1989).…”

Computer Modeling of Probable Decomposition Reactions: Cyclonitramines

“…In accordance with the amounts of CH 2 O, H 2 O, CO, and NO among products, we may explain the lack of NO 2 among them (compared to the expected amount) by secondary reactions (17) :…”