Hydrocarbon processes decomposition

Sulfuric acid, Sulfur trioxide Vervalin, H. C., Hydrocarbon Process., 1976, 55(9), 323 Dining sulfonation of 4-nitrotoluene at 32° C with 24% oleum in a 2000 1 vessel, a runaway decomposition reaction set in and ejected the contents as a carbonaceous mass. The thermal decomposition temperature was subsequently estimated as 52°C (but see above). 

Acetylene and mixtures of acetylene with light hydrocarbons are the raw materials for a process that has been used since the beginning of the 20th century. Unlike other hydrocarbons, the decomposition of acetylene is highly exothermic (AH = — 230 kJ/mol). 

Perovskite oxides are effective catalysts for various reactions, such as CO oxidation,total and partial oxidation of hydrocarbons, NOx decomposition, hydrogenation, " hydrogenolysis, and photocatalysis. Two types of catalytic processes are proposed for the catalysis of perovskites, namely, suprafacial and intrafacial catalysis." During suprafacial catalysis, the reactions between adsorbed species on the surface are much faster than reactions involving lattice oxygen, as in low-temperature oxidation of CO. In this case, the reaction rate appears to be correlated... 

Aromatization of preMAP Metabolites. Another spontaneous aromatization process has been observed for preMAP metabolites. PreMAP metabolites of naphthalene (77) and phenanthrene (78) have been shown to spontaneously aromatize to the parent hydrocarbon. The decomposition of 9,10-dihydro-9-hydroxy-10-( cysteinyl)phenanthrene has been proposed to occur through a thiiranium ion as shown in Equation 14. The isolation of the 9,10-dihydrodiol, and a phenol... 

During the gas-phase thermal decomposition of hydrocarbons, a carbonaceous material appears deposited on the surface that encloses the reacting environment. This deposit can give rise to operational difficulties in hydrocarbon processing equipment, such as increased pressure drops, plugging of pipes and valves and decreasing heat transfer efficiencies. 

Catalytic properties of complexes of multi-valenced metals with poly(ethylene glycol) (PEG) and polyurethane (PU) have been studied during liquid-phase oxidation processes such as the liquid-phase oxidation of hydrocarbons (phenanthrene, tetralin, cyclohexene), decomposition of hydroperoxides, hydrocarbons and decomposition of hydrogen peroxide [101 -106]. The kinetics of these reactions have been studied. The rate and selectivity of a particular reaction process depend not only on the properties... 

Hydrogen Production via Decomposition and Oxy-Decomposition of Natural Gas and Hydrocarbons Methane decomposition (or pyrolysis, dissociation, cracking) is a C02-free process for the production of hydrogen and carbon [12,13] ... 

MX of >99% purity can be obtained with the MGCC process with <1% MX left in the raffinate by phase separation of hydrocarbon layer from the complex-HF layer. The latter undergoes thermal decomposition, which Hberates the components of the complex. 

An excess of crotonaldehyde or aUphatic, ahcyhc, and aromatic hydrocarbons and their derivatives is used as a solvent to produce compounds of molecular weights of 1000—5000 (25—28). After removal of unreacted components and solvent, the adduct referred to as polyester is decomposed in acidic media or by pyrolysis (29—36). Proper operation of acidic decomposition can give high yields of pure /n j ,/n7 j -2,4-hexadienoic acid, whereas the pyrolysis gives a mixture of isomers that must be converted to the pure trans,trans form. The thermal decomposition is carried out in the presence of alkaU or amine catalysts. A simultaneous codistillation of the sorbic acid as it forms and the component used as the solvent can simplify the process scheme. The catalyst remains in the reaction batch. Suitable solvents and entraining agents include most inert Hquids that bod at 200—300°C, eg, aUphatic hydrocarbons. When the polyester is spHt thermally at 170—180°C and the sorbic acid is distilled direcdy with the solvent, production and purification can be combined in a single step. The solvent can be reused after removal of the sorbic acid (34). The isomeric mixture can be converted to the thermodynamically more stable trans,trans form in the presence of iodine, alkaU, or sulfuric or hydrochloric acid (37,38). 

Steam Reforming Processes. In the steam reforming process, light hydrocarbon feedstocks (qv), such as natural gas, Hquefied petroleum gas, and naphtha, or in some cases heavier distillate oils are purified of sulfur compounds (see Sulfurremoval and recovery). These then react with steam in the presence of a nickel-containing catalyst to produce a mixture of hydrogen, methane, and carbon oxides. Essentially total decomposition of compounds containing more than one carbon atom per molecule is obtained (see Ammonia Hydrogen Petroleum). 

Processes to produce boric acid esters are based on the azeotropic removal of water from a mixture of the appropriate alcohol, phenol, or glycol, and boric acid. A suitable hydrocarbon azeotroping agent is used to help remove the water. The water is removed continuously by using a condenser that allows continuous return of the solvent to the reaction vessel. Eor some borate esters, such as the glycol borates, distillation can result in decomposition. 

Carbon Composites. In this class of materials, carbon or graphite fibers are embedded in a carbon or graphite matrix. The matrix can be formed by two methods chemical vapor deposition (CVD) and coking. In the case of chemical vapor deposition (see Film deposition techniques) a hydrocarbon gas is introduced into a reaction chamber in which carbon formed from the decomposition of the gas condenses on the surface of carbon fibers. An alternative method is to mold a carbon fiber—resin mixture into shape and coke the resin precursor at high temperatures and then foUow with CVD. In both methods the process has to be repeated until a desired density is obtained. 

A number of processes have been used to produce carbon black including the oil-furnace, impingement (channel), lampblack, and the thermal decomposition of natural gas and acetjiene (3). These processes produce different grades of carbon and are referred to by the process by which they are made, eg, oil-furnace black, lampblack, thermal black, acetylene black, and channel-type impingement black. A small amount of by-product carbon from the manufacture of synthesis gas from Hquid hydrocarbons has found appHcations in electrically conductive compositions. The different grades from the various processes have certain unique characteristics, but it is now possible to produce reasonable approximations of most of these grades by the od-fumace process. Since over 95% of the total output of carbon black is produced by the od-fumace process, this article emphasizes this process. 

Tetrachloroethylene was first prepared ia 1821 by Faraday by thermal decomposition of hexachloroethane. Tetrachloroethylene is typically produced as a coproduct with either trichloroethylene or carbon tetrachloride from hydrocarbons, partially chloriaated hydrocarbons, and chlorine. Although production of tetrachloroethylene and trichloroethylene from acetylene was once the dominant process, it is now obsolete because of the high cost of acetylene. Demand for tetrachloroethylene peaked ia the 1980s. The decline ia demand can be attributed to use of tighter equipment and solvent recovery ia the dry-cleaning and metal cleaning iadustries and the phaseout of CFG 113 (trichlorotrifluoroethane) under the Montreal Protocol. 

The segregation process of graphite on the surface of a metal particle is similar to that proposed by Ober-lin and Endo[35] for carbon fibers prepared by thermal decomposition of hydrocarbons. Flowever, the... 

Fe, Co or Ni is also crucial in the catalytic decomposition of hydrocarbon. In order to efficiently obtain CNT and to control its shape, it is necessary and indispensable to have enough information on chemical interaction between carbon and these metals. It is quite easy for the catalytic synthesis method to scale up the CNT production (see Chap. 12). In this sense, this method is considered to have the best possibility for mass produetion. It is important to further improve the process of catalytie synthesis and, in order to do so, clarifieation of the mechanism of CNT growth is necessary to control the synthesis. CNT can be synthesized by the chemical reaction at relatively low... 

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