The Thermal Decomposition of Nitrate Esters. III. n-Propyl Nitrate<sup>1</sup>

Levy, Joseph B.; Adrian, Frank J.

doi:10.1021/ja01612a093

Cited by 12 publications

(8 citation statements)

References 2 publications

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“…The effect is due to the higher viscosity of mineral oil (S150N) and squalane as compared to hexadecane, and it is welldocumented for other solvents in the literature. 43,48 The diffusion of the alkoxy and NO 2 radicals (Figure 1) slows, as the solvent becomes more viscous. This cage effect causes the reverse of the RDS to become more significant, and the two radicals recombine to form the starting organic nitrate.…”

Section: Resultsmentioning

confidence: 99%

Chemistry of Organic Nitrates: Thermal Chemistry of Linear and Branched Organic Nitrates

Francisco

Krylowski

2005

Ind. Eng. Chem. Res.

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The objective of our research was to measure accurate rate constants for the thermal, unimolecular decomposition of organic nitrates. Our research confirms that the rate-determining step is homolytic cleavage of the weak O-N bond to form alkoxy radical and NO 2 , but the rate constants reported in the past are incorrect. The alkoxy radical and NO 2 engage in secondary reactions that ultimately generate stable products such as carbonyl and nitro compounds. Infrared spectroscopy (IR) and gas chromatography/mass spectrometry (GC/MS) were used to monitor the time dependent loss of organic nitrate and to characterize the products of the thermal reaction. Past research indicates that oxygen slows the rate of homolytic O-N bond cleavage to form radicals. Our research shows that the rates are the same in nitrogen as they are in air. The reaction in air produces R-β unsaturated ketones/aldehydes, which are not generated in a nitrogen atmosphere. The unsaturated ketone/aldehydes complicate the IR analysis, giving the appearance that the loss of organic nitrate slows down. Unhindered, linear organic nitrates have lower reaction rate constants than hindered organic nitrates. Activation energies were found to be lower for hindered organic nitrates. The steric strain present in the hindered organic nitrates may account for the weaker O-N bonds and faster thermal reaction rates. Reaction rates for thermal decomposition under nitrogen were found to decrease as the viscosity of the solvent increased.

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Section: Resultsmentioning

confidence: 99%

Chemistry of Organic Nitrates: Thermal Chemistry of Linear and Branched Organic Nitrates

Francisco

Krylowski

2005

Ind. Eng. Chem. Res.

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“…Thermal Decomposition of Isopropyl Nitrate. Levy and Adrian examined the decomposition of n -propyl nitrate at 181 °C, quantifying all decomposition products to account for 99% of the total nitrogen atoms. n -Propyl nitrite and nitroethane were formed in roughly equal amounts, while nitric oxide was produced in about half the quantity of either.…”

Section: Discussionmentioning

confidence: 99%

Fuel Combustion Additives: A Study of Their Thermal Stabilities and Decomposition Pathways

Oxley¹,

Smith²,

Rogers³

et al. 2000

Energy Fuels

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The purpose of this study was to evaluate whether a relationship exists between thermal stabilities of selected fuel additives and their effectiveness as diesel fuel cetane improvers. The additives were 2-ethylhexyl nitrate, isopropyl nitrate, tetraethylene glycol dinitrate, di(tert-butyl) peroxide, and methylcyclopentadienyl manganese tricarbonyl. Rate constants and activation parameters were determined for the thermolysis of the neat additives as well as the additives dissolved in various solvents and fuels. In all cases, decomposition kinetics were first-order. Mass spectral analysis was used to identify products from the thermal decomposition of the additives in various solutions. Thermal stability, as measured by the kinetics of decomposition, was not an accurate predictor of the effectiveness of the additives as cetane improvers. The effectiveness of a given additive appeared to correlate to the degree of molecular fragmentation rather than to thermal stability.

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“…This has been studied in ethyl nitrate (155,156,202,203,206,208) and -propyl nitrate (160). The chemical evidence that alkoxyl radicals play the role of intermediates in the decomposition of nitrites and nitrates is quite extensive.…”

Section: • -> Dimermentioning

confidence: 99%

“…in the gas phase yields 2-propanol as a minor product. It has been suggested (160) that the isopropoxyl radical abstracts a hydrogen atom from one of the other species present -acetone, acetaldehyde, or NOH-but it may also arise from disproportionation. Hydrogen abstraction from cyclohexene occurs in the gas phase at 195°C., the products including 19 per cent of the alcohol (22, 239).…”

Section: Isopropoxyl Radicalmentioning

confidence: 99%

The Thermochemistry And Reactivity Of Alkoxyl Radicals

Gray¹,

Williams²

1959

Chem. Rev.

257

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The Thermal Decomposition of Nitrate Esters. III. n-Propyl Nitrate¹

Cited by 12 publications

References 2 publications

Chemistry of Organic Nitrates: Thermal Chemistry of Linear and Branched Organic Nitrates

Chemistry of Organic Nitrates: Thermal Chemistry of Linear and Branched Organic Nitrates

Fuel Combustion Additives: A Study of Their Thermal Stabilities and Decomposition Pathways

The Thermochemistry And Reactivity Of Alkoxyl Radicals

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The Thermal Decomposition of Nitrate Esters. III. n-Propyl Nitrate1

Cited by 12 publications

References 2 publications

Chemistry of Organic Nitrates: Thermal Chemistry of Linear and Branched Organic Nitrates

Chemistry of Organic Nitrates: Thermal Chemistry of Linear and Branched Organic Nitrates

Fuel Combustion Additives: A Study of Their Thermal Stabilities and Decomposition Pathways

The Thermochemistry And Reactivity Of Alkoxyl Radicals

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The Thermal Decomposition of Nitrate Esters. III. n-Propyl Nitrate¹