THE THERMAL DECOMPOSITION OF CARBOHYDRATES

1948 ◽  
Vol 26b (4) ◽  
pp. 415-431 ◽  
Author(s):  
I. E. Puddington
Keyword(s):  
Carbon Dioxide ◽  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Reaction Temperature ◽  
Potato Starch ◽  
Second Step ◽  
Volatile Solids ◽  
Volatile Products ◽  
Separate Step ◽  
Rapid Reaction

The thermal decompositions of cellobiose, maltose, dextrose, and potato starch have been studied over a temperature range, by following the production of volatile products. Carbon dioxide, carbon monoxide, and water with small quantities of acids, aldehydes, and volatile solids were produced in all cases. With cellobiose, the first step of the reaction, which involved the elimination of two moles of water per mole of sugar, could be separated from the second step, where the oxides of carbon were produced, by controlling the reaction temperature. Dextrose first dimerized by a rapid reaction and then decomposed in much the same manner as cellobiose. The behavior of maltose was anomalous and no dehydration by a separate step could be detected. The decomposition of potato starch was similar to the second step of the cellobiose reaction.

scholarly journals Thermal decomposition of potassium titanium oxalate

2011 ◽  
Vol 76 (7) ◽  
pp. 1015-1026 ◽  
Author(s):  
Karuvanthodi Muraleedharan ◽  
Labeeb Pasha
Keyword(s):  
Carbon Dioxide ◽  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Model Fitting ◽  
Nitrogen Atmosphere ◽  
Single Step ◽  
Heating Rates ◽  
Decomposition Stage ◽  
Model Free ◽  
Good Agreement

The thermal decomposition of potassium titanium oxalate (PTO) was studied using non-isothermal thermogravimetry at different heating rates under a nitrogen atmosphere. The thermal decomposition of PTO proceeds mainly through five stages forming potassium titanate. The theoretical and experimental mass loss data are in good agreement for all stages of the thermal decomposition of PTO. The third thermal decomposition stage of PTO, the combined elimination of carbon monoxide and carbon dioxide, were subjected to kinetic analyses both by the method of model fitting and by the model free approach, which is based on the isoconversional principle. The model free analyses showed that the combined elimination of carbon monoxide and carbon dioxide and formation of final titanate in the thermal decomposition of PTO proceeds through a single step with an activation energy value of about 315 kJ mol-1.

Dehydrogenation of Ethane and Hydrogenation of Carbon Dioxide in a Catalytic Membrane Reactor Using Copper-Plated LaNi5 as a Membrane Material

2006 ◽  
Vol 4 (1) ◽  
Author(s):  
Yoshimitsu Uemura ◽  
Kazuyuki Morita ◽  
Yoshihiro Ohzuno ◽  
Yasuo Hatate
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Membrane Reactor ◽  
Second Step ◽  
Catalytic Membrane ◽  
Membrane Material ◽  
Catalytic Membrane Reactor ◽  
Separation Membrane ◽  
Reduce Carbon Dioxide ◽  
Hydrogenation Of Carbon Dioxide

A membrane reactor consisting of a reactor and a separation membrane may be suitable to provide hydrogen from hydrocarbon in order to reduce carbon dioxide. In this study, a catalytic membrane reactor, a type of membrane reactor, was designed and tested to prove if both the reactions (dehydrogenation of ethane, and reduction of carbon dioxide to carbon monoxide) occur on each side of the membrane in the reactor as expected. As membrane materials, copper-plated LaNi5 and CaNi5 were chosen. In the first step, lower hydrocarbons including ethane was dehydrogenated at one side of the membrane; another side was swept by an inert gas. In the second step, simultaneous feed of ethane (one side) and carbon dioxide (another side) was tried if both the reactions (dehydrogenation of ethane and reduction of carbon dioxide) occur. Carbon dioxide was reduced to carbon monoxide; ethane was dehydrogenated to give ethene.

THE THERMAL DECOMPOSITION OF PHENYLACETIC ACID

1960 ◽  
Vol 38 (8) ◽  
pp. 1261-1270 ◽  
Author(s):  
Margaret H. Back ◽  
A. H. Sehon
Keyword(s):  
Carbon Dioxide ◽  
Activation Energy ◽  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Rate Constant ◽  
Phenylacetic Acid ◽  
Order Process ◽  
First Order ◽  
Kinetics Of ◽  
Dissociation Step

The thermal decomposition of phenylacetic acid was investigated by the toluene-carrier technique over the temperature range 587 to 722 °C. The products of the pyrolysis were carbon dioxide, carbon monoxide, hydrogen, methane, dibenzyl, and phenylketene. From the kinetics of the decomposition it was concluded that the reaction[Formula: see text]was a homogeneous, first-order process and that the rate constant of this dissociation step was represented by the expression k = 8 × 1012.e−55,000/RT sec−1. The activation energy of this reaction may be identified with D(C6H5CH2—COOH). The possible reactions of carboxyl radicals are discussed.

The reaction of methanol vapour with silver(I) oxide

1964 ◽  
Vol 17 (5) ◽  
pp. 529
Author(s):  
JA Allen
Keyword(s):  
Carbon Dioxide ◽  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Gas Phase ◽  
Kinetic Data ◽  
Kcal Mole ◽  
Collision Model ◽  
Temperature Range ◽  
Methanol Vapour ◽  
The Mean

The reaction of methanol with silver(I) oxide has been studied in the temperature range 56.5-78.4�. For complete reduction of the oxide at 78.4�, the available oxygen is fully accounted for by the products, formaldehyde, formic acid, carbon monoxide, carbon dioxide, and water. In the temperature range 56.5-70.2� the net measured rates of formation of these products are expressed by equations of the form, ������������������ rate = Aexp(-E/RT), and the kinetic data are interpreted as the consecutive formation of the products on the surface without complete desorption to the gas phase between each step. For the dominant product, carbon dioxide, at the mean temperature the values of A and E are 1028.5 μg oxygen per minute and 41.3 kcal mole-1 respectively. The former is interpreted in terms of a simple collision model and the latter compared with values obtained for the thermal decomposition of the oxide.

scholarly journals Controlled atmosphere GMAW welding of transportation vehicles and production machines parts made from 30MnB5 steel

2018 ◽  
Vol 216 ◽  
pp. 03001 ◽  
Author(s):  
Evgeny Ivanayskiy ◽  
Aleksei Ishkov ◽  
Aleksandr Ivanayskiy ◽  
Iakov Ochakovskii
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Chemical Composition ◽  
Controlled Atmosphere ◽  
Shielding Gas ◽  
Reducing Atmosphere ◽  
Metal Composition ◽  
Gmaw Welding ◽  
Welding Materials

The paper studies the influence of shielding gas on the composition and the structure of weld joint metal of 30MnB5 steel applied in essential parts of automobiles and tractors. The welding was performed in inert, oxidizing and reducing atmospheres. It was established that TIG welding with argon used as shielding gas did not provide the required mechanical properties when using conventional welding materials. Carbon dioxide during MAG welding caused partial burning of alloying elements. Carbon monoxide used as shielding gas was proved to form reducing atmosphere enabling to obtain chemical composition close to the base metal composition. Metallographic examinations were carried out. The obtained results provided full-strength weld, as well as the required reliability and durability of welded components and joints.

Low-Carbon Monoxide Hydrogen by Sorption-Enhanced Reaction

2003 ◽  
Vol 1 (1) ◽  
Author(s):  
Douglas P Harrison ◽  
Zhiyong Peng
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Hydrogen Production ◽  
Proton Exchange Membrane ◽  
Primary Energy ◽  
Proton Exchange ◽  
Raw Material ◽  
Impurity Level ◽  
Low Carbon ◽  
Enhanced Production

Hydrogen is an increasingly important chemical raw material and a probable future primary energy carrier. In many current and anticipated applications the carbon monoxide impurity level must be reduced to low-ppmv levels to avoid poisoning catalysts in downstream processes. Methanation is currently used to remove carbon monoxide in petroleum refining operations while preferential oxidation (PROX) is being developed for carbon monoxide control in fuel cells. Both approaches add an additional step to the multi-step hydrogen production process, and both inevitably result in hydrogen loss. The sorption enhanced process for hydrogen production, in which steam-methane reforming, water-gas shift, and carbon dioxide removal reactions occur simultaneously in the presence of a nickel-based reforming catalyst and a calcium-based carbon dioxide sorbent, is capable of producing high purity hydrogen containing minimal carbon monoxide in a single processing step. The process also has the potential for producing pure CO2 that is suitable for subsequent use or sequestration during the sorbent regeneration step. The current research on sorption-enhanced production of low-carbon monoxide hydrogen is an extension of previous research in this laboratory that proved the feasibility of producing 95+% hydrogen (dry basis), but without concern for the carbon monoxide concentration. This paper describes sorption-enhanced reaction conditions – temperature, feed gas composition, and volumetric feed rate – required to produce 95+% hydrogen containing low carbon monoxide concentrations suitable for direct use in, for example, a proton exchange membrane fuel cell.

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