Dependence of 1,2-propanediol yield on formaldehyde concentration in γ-radiolysis of ethanol-formaldehyde system at 373–473 K

Novoselov, A. I.; Silaev, Michael M.; Bugaenko, L.T.

doi:10.1134/s0018143907010110

Cited by 10 publications

(8 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Free 1-hydroxyalkyl radicals, which result from the abstraction of a hydrogen atom from the carbon atom bonded to the hydroxyl group in molecules of saturated aliphatic alcohols except methanol under the action of chemical initiators, 29,30 light, 17,31 or ionizing radiation, 32,33 add at the double bond of free formaldehyde dissolved in the alcohol, forming 1,2-alkanediols, 8,9,12,[29][30][31][32][33][34][35][36] carbonyl compounds, and methanol 8,33 via the chain mechanism. The yields of the latter two products in the temperature range of 303 to 448 K are one order of magnitude lower.…”

Section: Addition Of Free 1-hydroxyalklyl Radicals With Two or More Cmentioning

confidence: 99%

Kinetic Equations of Free-Radical Nonbranched-Chain Processes of Addition

Silaev¹

2018

ECB

Self Cite

View full text Add to dashboard Cite

The aim of this study was to devise simple kinetic equations to describe ab initio initiated nonbranched-chain processes of addition of saturated free-radical to double bonds of unsaturated molecules in binary reaction systems of saturated and unsaturated components. In these processes the formation rate of the molecular addition products (1:1 adducts) as a function of concentration of the unsaturated component reaches a limiting value. Five reaction schemes are suggested for the addition processes. The proposed schemes include the reaction competing with chain propagation reactions through a reactive free radical. The chain evolution stage in these schemes involves three or four types of free radicals. One of them is relatively low-reactive and inhibits the chain process by shortening of the kinetic chain length. Based on the suggested schemes, nine rate equations are deduced using quasi-steady-state treatment. These equations provide good fits for the non-monotonic (peaking) dependences of the formation rates of the molecular products (1:1 adducts) on the concentration of the unsaturated component in the binary systems. The unsaturated compound in these systems is both a reactant and an autoinhibitor generating low-reactive free radicals. A similar kinetic description is applicable to the nonbranched-chain process of the free-radical hydrogen oxidation, in which the oxygen with the increase of its concentration begins to act as an oxidation autoinhibitor (or an antioxidant). The energetics of the key radical-molecule reactions are considered.

show abstract

Section: Addition Of Free 1-hydroxyalklyl Radicals With Two or More Cmentioning

confidence: 99%

Kinetic Equations of Free-Radical Nonbranched-Chain Processes of Addition

Silaev¹

2018

ECB

Self Cite

View full text Add to dashboard Cite

show abstract

“…Free 1-hydroxyalkyl radicals (which result from the abstraction of a hydrogen atom from the carbon atom bonded to the hydroxyl group in molecules of saturated aliphatic alcohols but methanol under the action of chemical initiators [29,30], light [17,31], or ionizing radiation [32,33]) add at the double bond of free formaldehyde dissolved in the alcohol, forming 1,2-alkanediols [8,9,12,[29][30][31][32][33][34][35][36], carbonyl compounds, and methanol [8,33] via the chaining mechanism. (The yields of the latter two products in the temperature range of 303 to 448K are one order of magnitude lower.)…”

Section: More Carbon Atomsmentioning

confidence: 99%

Untitled

2018

AOICS

View full text Add to dashboard Cite

The aim of this study was the conclusion of simple kinetic equations to describe ab initio initiated Nonbranched-chain processes of the saturated free-radical addition to the double bonds of unsaturated molecules in the binary reaction systems of saturated and unsaturated components. In the processes of this kind the formation rate of the molecular addition products (1:1 adducts) as a function of concentration of the unsaturated component has a maximum. Five reaction schemes are suggested for this addition processes. The proposed schemes include the reaction competing with chain propagation reactions through a reactive free radical. The chain evolution stage in these schemes involves three or four types of free radicals. One of them is relatively low-reactive and inhibits the chain process by shortening of the kinetic chain length. Based on the suggested schemes, nine rate equations (containing one to three parameters to be determined directly) are deduced using quasi-steady-state treatment. These equations provide good fits for the no monotonic (peaking) dependences of the formation rates of the molecular products (1:1 adducts) on the concentration of the unsaturated component in binary systems consisting of a saturated component (hydrocarbon, alcohol, etc.) and an unsaturated component (alkene, allyl alcohol, formaldehyde, or dioxygen). The unsaturated compound in these systems is both a reactant and an autoinhibitor generating low-reactive free radicals. A similar kinetic description is applicable to the Nonbranchedchain process of the free-radical hydrogen oxidation, in which the oxygen with the increase of its concentration begins to act as an oxidation autoingibitor (or an antioxidant). The energetics of the key radical-molecule reactions is considered.

show abstract

“…Free 1-hydroxyalkyl radicals (which result from the abstraction of a hydrogen atom from the carbon atom bonded to the hydroxyl group in molecules of saturated aliphatic alcohols but methanol under the action of chemical initiators [9,10], light [11,12], or ionizing radiation [13,14]) add at the double bond of free formaldehyde dissolved in the alcohol, forming 1,2alkanediols [7][8][9][10][12][13][14][15][16][17][18], carbonyl compounds, and methanol [14,15] via the chaining mechanism. (The yields of the latter two products in the temperature range of 303 to 448 K are one order of magnitude lower).…”

Section: Addition Of 1-hydroxyalklyl Free Radicals With Two or More Cmentioning

confidence: 99%

Free Unsolvated Formaldehyde in Solutions: Influence of Temperature, Solvent Permittiity, and Total Formaldehyde Concentration

Silaev¹

2015

J. Appl. Sol. Chem. Model.

View full text Add to dashboard Cite

A mechanism of the initiated nonbranched-chain process of forming 1,2-alkanediols and carbonyl compounds in alcohol-formaldehyde systems is suggested. The quasi-steady-state treatment is used to obtain kinetic equations that can describe the nonmonotonic (with a maximum) dependences of the formation rates of the products on the concentration of free unsolvated formaldehyde. The experimental concentration of the free unsolvated form of formaldehyde are given at the different temperatures, solvent permittivity and total concentrations of formaldehyde in water and alcohols. An empirical equation for calculating the free formaldehyde concentration in alcohol-formaldehyde (including water/ethanediol-formaldehyde) systems at various temperatures and total formaldehyde concentrations and an equation for evaluating solvent concentrations in these systems were derived.

show abstract

Dependence of 1,2-propanediol yield on formaldehyde concentration in γ-radiolysis of ethanol-formaldehyde system at 373–473 K

Cited by 10 publications

References 0 publications

Kinetic Equations of Free-Radical Nonbranched-Chain Processes of Addition

Kinetic Equations of Free-Radical Nonbranched-Chain Processes of Addition

Untitled

Free Unsolvated Formaldehyde in Solutions: Influence of Temperature, Solvent Permittiity, and Total Formaldehyde Concentration

Contact Info

Product

Resources

About