Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

The Kinetics of the Thermal Decomposition of Normal Paraffin Hydrocarbons. V. Order of Reaction Over Extended Ranges of Pressure

F. J. Stubbs, K. U. Ingold, B. C. Spall, C. J. Danby and Cyril Hinshelwood
Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences
Vol. 214, No. 1116 (Aug. 7, 1952), pp. 20-35
Published by: Royal Society
Stable URL: http://www.jstor.org/stable/99156
Page Count: 16
  • Read Online (Free)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
The Kinetics of the Thermal Decomposition of Normal Paraffin Hydrocarbons. V. Order of Reaction Over Extended Ranges of Pressure
Preview not available

Abstract

Previous papers have provided evidence that the decomposition of a paraffin reduced to its limiting rate by nitric oxide is a molecular reaction. This reaction has an unusual pressure dependence, which has now been studied over a wider range, namely, up to 1600 mm, and down to 0· 1 mm. In the higher part of the pressure range the reaction order changes from nearly the second to the first with increase in the initial pressure, as now confirmed by extended measurements on n-butane and n-pentane. In the lower part of the range another transition from second order to first with rise of pressure can be found, and is here shown by measurements on ethane, propane, n-butane, n-pentane and n-hexane. Thus with higher normal paraffins the reaction order is the second at the lowest pressure, decreases to the first, increases again towards the second and finally returns to the first at the highest pressure. Where this behaviour is shown the activation energy is also a function of the pressure. The activation energy for ethane is not a function of the pressure and, correspondingly, there is here a single transition from the second order at the lowest pressure to the first order at about 400 mm and up to at least 1600 mm. Over the range of pressure where the composite behaviour is observed, mass spectrometer analysis of the butane products reveals no important change in the relative probability of rupture at the C1-2 and C2-3 linkages respectively. In the region of the lower pressures, however, some of the primarily formed ethane splits to give ethylene and hydrogen more rapidly than can be accounted for by the decomposition rate of ethane as directly determined for comparable conditions.

Page Thumbnails

  • Thumbnail: Page 
20
    20
  • Thumbnail: Page 
21
    21
  • Thumbnail: Page 
22
    22
  • Thumbnail: Page 
23
    23
  • Thumbnail: Page 
24
    24
  • Thumbnail: Page 
25
    25
  • Thumbnail: Page 
26
    26
  • Thumbnail: Page 
27
    27
  • Thumbnail: Page 
28
    28
  • Thumbnail: Page 
29
    29
  • Thumbnail: Page 
30
    30
  • Thumbnail: Page 
31
    31
  • Thumbnail: Page 
32
    32
  • Thumbnail: Page 
33
    33
  • Thumbnail: Page 
34
    34
  • Thumbnail: Page 
35
    35