Cracking of squalene into isoprene as chemical utilization of algae oil

2020 ◽  
Vol 22 (10) ◽  
pp. 3083-3087
Author(s):  
Kazuya Kimura ◽  
Kazuma Shiraishi ◽  
Takahiro Kondo ◽  
Junji Nakamura ◽  
Tadahiro Fujitani

Thermal decomposition of squalene proceeds as a chain reaction to produce isoprene (C5H8) and C10 hydrocarbons.

The thermal decomposition of acetaldehyde, propionaldehyde, n -butyraldehyde and iso-butyraldehyde, as investigated by the static method, is essentially homogeneous, inhibitable by propylene, isobutene and small amounts of nitric oxide, and generally catalyzed at high inhibitor concentrations. The kinetic order of the uninhibited decomposition exhibits little obvious regularity, but that of the maximally inhibited reaction is approximately 1.5 for all three inhibitors. Kates of the uninhibited decomposition do not follow the sequence in the homologous series, and there is no systematic variation in the extent of inhibition from one aldehyde to another. For each aldehyde, the minimum rates for the three inhibitors in general are not identical, nevertheless exhibit a correspondence probably close enough to eliminate chance coincidence. The kinetic and analytical results of the uninhibited decomposition can be approximately described by a Kice-Herzfeld-type mechanism, with the kinetics in each case largely determined by the stability of radicals and their reactions in chain propagation and termination. The question whether the maximally inhibited reaction is a molecular reaction or a chain reaction is surveyed. Although the results cannot be completely accounted for by a molecular reaction alone, a chain mechanism for propylene inhibition involving allyl radicals likewise has only limited success. For nitric-oxide inhibition, it is not certain how far the results are affected by the occurrence of the subsequent catalyzed reaction. No definite conclusion can thus be reached about the nature of the maximally inhibited reaction.


1969 ◽  
Vol 47 (16) ◽  
pp. 3031-3039 ◽  
Author(s):  
R. J. Acheson ◽  
P. W. M. Jacobs

The thermal decomposition of anhydrous barium perchlorate to barium chloride and oxygen has been studied by pressure measurements, or by weight loss, in vacuo, under the accumulated gaseous products (0–3 Torr oxygen), under dry air or nitrogen, and mixed with added barium chloride. The plots of fractional decomposition (α) against time (t) are complex, as would be expected for a reaction proceeding via unstable intermediates. The most pronounced features of the α(t) curves are an initial acceleratory period, which is succeeded by an approximately linear period and then, after a sharp break (reduction in rate), by a deceleratory period which conforms to the contracting-volume kinetic law. The latter stage is associated with the decomposition of barium chlorate and has an activation energy of 59 kcal/mole. The first two stages comprise the decomposition of perchlorate to chlorate with the approximate stoichiometry 3ClO4− = 2ClO3− + Cl− + 3O2. A chain reaction sequence, which involves O atoms as chain carriers, is proposed for these stages. The effect of the removal of products, of increasing the ambient pressure of inert gas, and of the addition of barium chloride, can all be explained on this model.


1951 ◽  
Vol 29 (6) ◽  
pp. 508-525 ◽  
Author(s):  
W. R. Trost ◽  
R. L. McIntosh

The thermal decomposition of the gas disulphur decafluoride has been studied in a metal reactor. Analytical evidence showed that the reaction proceeds according to the equation S2F10 = SF6 + SF4.The reaction was found to be largely homogeneous, as the heterogeneous reaction accounted for less than 5% of the total process. The homogeneous reaction was shown to be first order, and in the temperature range investigated the rate is given by ln k = 47.09 − 49,200/RT. A chain reaction is postulated to explain the observed rate of the reaction. The effect of nitric oxide and acetylene dichloride on the rate and products of the reaction was investigated.


1947 ◽  
Vol 20 (3) ◽  
pp. 609-617 ◽  
Author(s):  
J. L. Holland ◽  
Geoffrey Gee

Abstract A brief review is given of kinetic work on the oxidation of representative mono, 1,4 and 1,5 olefins. The essential process in each case is identified as a chain reaction in which hydrocarbon radicals are formed, absorb oxygen, and then react with another molecule of olefin to give a hydroperoxide and a new free radical. Three methods of chain initiation are considered: (1) direct attack of oxygen on the olefin, (2) thermal decomposition of the hydroperoxide, (3) thermal decomposition of added benzoyl peroxide. Chain termination results from interaction of two free radicals; except at low oxygen pressures, these are both peroxidic.


Author(s):  
J. E. Hobbs ◽  
Cyril Norman Hinshelwood

In a recent paper (Hobbs and Hinshelwood 1938), information about the chain mechanisms involved in the thermal decomposition of ethane was obtained by studying the variation with the ethane concentration of the shape of the curve which represents in the reaction rate as a function of minute quantities of added nitric oxide. This paper describes the results of a similar investigation carried out with diethyl ether, the behaviour of which shows an interesting contrast with that of ethane. The thermal decomposition of diethyl ether in the neighbourhood of 500° C. occurs partly by a chain mechanism in which free radicals are formed, and partly by intramolecular rearrangement (Staveley and Hinshelwood 1936, 1937). The end- products of the decomposition are methane, ethane, and carbon monoxide, with small amounts of hydrogen and unsaturated substances. Acetaldehyde is an intermediate product formed either in the rearrangement process, or, as in the mechanism put formed below, during the chain reaction (Fletcher and Rollefson 1936). The acetaldehyde, however, decomposes rapidly under the experimental conditions and the initial rate is sensibly that of the decomposition of the ether into final products.


1963 ◽  
Vol 10 (02) ◽  
pp. 400-405 ◽  
Author(s):  
B. A Amundson ◽  
L. O Pilgeram

SummaryEnovid (5 mg norethynodrel and 0.075 mg ethynylestradiol-3-methyl ether) therapy in young normal human subjects causes an increase in plasma fibrinogen of 32.4% (P >C 0.001). Consideration of this effect together with other effects of Enovid on the activity of specific blood coagulatory factors suggests that the steroids are exerting their effect at a specific site of the blood coagulation and/or fibrinolytic system. The broad spectrum of changes which are induced by the steroids may be attributed to a combination of a chain reaction and feed-back control.


2021 ◽  
Vol 11 (2) ◽  
pp. 77-93
Author(s):  
Khalid O. Alfarouk ◽  
Sari T. S. AlHoufie ◽  
Samrein B. M. Ahmed ◽  
Mona Shabana ◽  
Ahmed Ahmed ◽  
...  

COVID-19, occurring due to SARS-COV-2 infection, is the most recent pandemic disease that has led to three million deaths at the time of writing. A great deal of effort has been directed towards altering the virus trajectory and/or managing the interactions of the virus with its subsequent targets in the human body; these interactions can lead to a chain reaction-like state manifested by a cytokine storm and progress to multiple organ failure. During cytokine storms the ratio of pro-inflammatory to anti-inflammatory mediators is generally increased, which contributes to the instigation of hyper-inflammation and confers advantages to the virus. Because cytokine expression patterns fluctuate from one person to another and even within the same person from one time to another, we suggest a road map of COVID-19 management using an individual approach instead of focusing on the blockbuster process (one treatment for most people, if not all). Here, we highlight the biology of the virus, study the interaction between the virus and humans, and present potential pharmacological and non-pharmacological modulators that might contribute to the global war against SARS-COV-2. We suggest an algorithmic roadmap to manage COVID-19.


1980 ◽  
Vol 20 (18) ◽  
pp. 1197-1204 ◽  
Author(s):  
H. T. Chen ◽  
P. A. Chartier ◽  
S. Setthachayanon

Author(s):  
R. O. Ayeni

AbstractA chain reaction of oxygen (reactant) and hydrogen (active intermediary) with mtrosyl chloride (sensitizer) as a catalyst may be modelled mathematically as a non-isothermal reaction. In this paper we present an asymptotic analysis of a spatially homogeneous model of a non-isothermal branched-chain reaction. Of particular interest is the so-called explosion time and we provide an upper bound for it as a function of the activation energy which can vary over all positive values. We also establish a bound on the temperature when the activation energy is finite.


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