Bajus, M.; Vesely, V.; Leclercq, P.A.; Rijks, J.A. Published in:Industrial and Engineering Chemistry. Product Research and Development DOI:10.1021%2Fi360069a007 10.1021/i360069a007Published: 01/01/1979 Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Link to publication• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. 1, 1979 Gandhi, H. S., Sheief, M., J , Catal., 24, 241 (1972).Gregg, S. J., Sing, K. S. W., "Adsorption, Surface Area and Porosity", Academic Hirota, K., Kera, Y., Teratani, S., J . Phys. Chem., 59, 388 (1955 (1 973).(USSR) 15, 408 (1974). (1972). GENERAL ARTICLESShvets, V. A., Kazanskii, V. B., J . Catal., 25, 123 (1972). Shvets, V. A.. Sarichev, M. E., Kazanskii, V. B., J. Catal., 11, 378 (1968) , 1424 (1955). 3rd, 1964 (1965). Catalysis", Academic Press, New York, N.Y., 1967. 597 (1971. 1966.Received for review February 13, 1978 Accepted The thermal decomposition of heptane in the presence of steam was studied in a flow reactor with large inner surface. The experiments were performed at atmospheric pressure in a temperature range of 680-760 OC for a mass ratio of steam to hydrocarbon 3 : l . The reaction products were analyzed by gas chromatography. For the identification both comparison of retention indices with those of standard compounds and literature data and mass spectrometry were used. The conversion process appeared to be a first-order reaction with a frequency factor of 1.34 X 10'' s-' and an activation energy of 195.5 kJ mol-'. The composition of the mixture of reaction products was in agreement with the Rice-Kossiakoff theory, except for ethane and 1-hexene.

Reduction of the column diameter has proved to be a highly efficient tool to increase the speed of analysis. Unfortunately, the requirements for instrumental design with respect to sample input band width, low dead volume interfacing, and time constants of detection and registration systems are the more critical the smaller the inside diameter. Recently we reported input band widths as low as 1 ms [1] for gaseous samples at ppm concentration levels, without any preconcentration, in a study with narrow bore columns and thermal conductivity detection. In this study a simple versatile micro on‐column cold trap/thermodesorption enrichment system for narrow bore columns is introduced and evaluated. The combination of considerable sample enrichment and preservation of the compatibility of the required input band width with column dimensions is critically examined. The process of thermodesorption (reinjection) which is the most critical step, is particularly emphasized. The system consists of a short aluminum coated fused silica or metal capillary with a low mass and a low cost electrical heating. Input band widths down to 1 ms are obtained without extreme demands on electrical power (300 watt). The potential of the system is illustrated with some extremely fast separations.

SummaryDirect conversion of isothermal to temperature programmed indices is not possible. In this work it is shown that linear temperature programmed retention indices can only be calculated from isothermal retention data if the temperature dependence of both the distribution coefficients and the column dead time are taken into account.Procedures are described which allow calculation of retention temperatures and from these, accurate programmed retention indices. Within certain limits the initial oven temperature and programming rate can be chosen freely.The prerequisite forthis calculation is the availability of reliable isothermal retention data (retention times, retention factors, relative retention times, or retention indices) at two different temperatures for one column.The use of compiled isothermal retention indices at twodifferent temperatures for the calculation of retention temperatures and thus temperature programmed indices is demonstrated. For the column for which programmed retention indices have to be determined, the isothermal retention times of the n-alkanes and the column dead time as a function of temperature have to be known in addition to the compiled data for a given stationary phase.Once the programmed retention indices have been calculated for a given column the concept allows the calculation of temperature programmed indices for columns with different specifications. The characteristics which can be varied are: column length, column inner diameter, phase-ratio, initial oven temperature, and programming rate.

Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers)Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Link to publication• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. The effect of thiophene on the kinetics and selectivity of the conversion of hydrocarbons by steam cracking was studied in a stainless steel tubular reactor with relatively large inner surface. Heptane was selected as a model and decomposed at 700 O C and 100 kPa with a mass ratio of steam to feed of 3:l. The rate of decomposition increased about 14% if 0.1 and 0.5% mass of thiophene was added, but was unchanged if 1 % was present.The influence of thiophene on the selectivity of the conversion of heptane to ethene appeared to depend on the residence time. The effect of thiophene on the formation of coke was investigated in the pyrolysis of a reformer raffinate in a stainless steel flow reactor at 820 O C , without steam. Coking is lessened with increasing amounts of thiophene in the feed (0.05-0.5 % mass). Reaction mechanisms are suggested.

. (1983). Steam cracking of hydrocarbons 6. Effect of dibenzyl sulfide and dibenzyl disulfide on reaction kinetics and coking. Industrial and Engineering Chemistry. Product Research and Development, 22(2), 335-343. DOI: 10.1021%2Fi300010a033, 10.1021/i300010a033 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. The influence of aromatic sulfides on the kinetics and selectivity of hydrocarbon conversion by steam cracking and on pyrolytic coke formation was investigated in stainless steel tubular reactors with relatively large inner surface.The rate of decomposition of heptane (at 700 'C, 100 kPa, and a mass ratio of steam to feed 3:l) increased by 16 to 26 % , and the selectivity toward ethene decreased, if 0.1 to 1 .O % mass of dibenzyl sulfide, relative to heptane, was added. Addiiion of 1 % mass dibenzyl disulfide increased the decomposition rate of heptane by 8 % . Increasing amounts of the title compounds (0.1, 0.5% mass) in the feed decreased coking up to 70% in the pyrolysis of reformer raffinate at 820 O C , without steam. The decreased coking in turn caused an increased aromatic content in the liquid pyrolysis product mixtures. Based on the analytical results, obtained by capillary gas chromatography-mass spectrometry, reaction mechanisms are suggested.