Petroleum products reaction mechanism

In many instances, two or more miscible liquids must be mixed to give a product of a desired specification, such as, for example, in the blending of petroleum products of different viscosities. This is the simplest type of mixing as it involves neither heat nor mass transfer, nor indeed a chemical reaction. Even such simple operations can however pose problems when the two liquids have vastly different viscosities. Another example is the use of mechanical agitation to enhance the rates of heat and mass transfer between the wall of a vessel, or a coil, and the liquid. Additional complications arise in the case of highly viscous Newtonian and non-Newtonian liquids. 

Biodegradation is perhaps the most important reaction mechanism for the degradation of hydrocarbons in aquatic environments. Aliphatic compounds in cmde oil and petroleum products are readily degraded, with a prominent initial microbial preference for straight chain compounds (e.g.. Atlas and Bartha, 1992 Prince, 1993 Volkman et al., 1997 Wang et al., 1999 Heider... 

While natural gas reforming is the primary process for the industrial production of H2, the reforming of other gaseous hydrocarbons such as ethane, propane, and n-butane have been explored for the production of H2 for fuel cells.52,97 The reforming of propane and n-butane received particular attention in recent years, because they are the primary constituents of liquefied petroleum gas (LPG), which is available commercially and can be easily transported and stored on-site. LPG could be an attractive fuel for solid oxide fuel cells (SOFCs) and PEMFCs for mobile applications.98 01 The chemistry, thermodynamics, catalysts, kinetics, and reaction mechanism involved in the reforming of C2-C4 hydrocarbons are briefly discussed in this section. 

The complex nature of the HDS and HDN problems requires a broad, transdisciplinary approach in order to try to answer the most varied questions related to these important classes of reactions. The key issues include the practical aspects related to process and product engineering, a precise knowledge of the nature and the composition of petroleum and of refinery fractions, and the thermodynamics and detailed kinetics of the different processes involved. Also, a number of more fundamental solid-state and surface chemistry considerations regarding the preparation, the characterization, and the resulting properties of HDS and HDN catalysts, as well as the complicated reaction mechanisms involved for the various important families of substrates, need to be understood in depth. Even though some very impressive achievements have been disclosed over the last 30-40 years, it seems that some of the major new discoveries desired today may have been held back by the lack of a better understanding of some key issues. Of particular importance are the nature and the structure of HDS-HDN active sites on metal sulfide catalysts, and the intimate details of the elementary reactions implicated in the commonly accepted catalytic schemes. 

The aromatization of mixed-C4 hydrocarbons, prevalent by-products derived from petroleum refining processes, over HZSM-5 catalysts modified by both Zn and Ni cations via different impregnating methods has been systematically studied in two different sizes of reactors at various temperatures and space velocities of the feeds. The reaction mechanisms were discussed according to the liquid and gas product distributions. The acidity of the catalysts were also characterized using the frequency response (FR). 

The involvement of aromatic C - N<, especially derivatives from carbazoles, is not definite yet. Such a mechanism would be desired to reduce hydrogen consumption. HDO is not an important reaction for petroleum products, but it is very important in stabilizing coal-derived liquids. HDO of dibenzofuran is very slow. An acidic support is helpful for the HDO of dibenzofuran species. 

Into a 1-litre beaker, provided with a mechanical stirrer, place 36 - 8 g. (36 ml.) of aniline, 50 g. of sodium bicarbonate and 350 ml. of water cool to 12-15° by the addition of a little crushed ice. Stir the mixture, and introduce 85 g. of powdered, resublimed iodine in portions of 5-6 g, at intervals of 2-3 minutes so that all the iodine is added during 30 minutes. Continue stirring for 20-30 minutes, by which time the colour of the free iodine in the solution has practically disappeared and the reaction is complete. Filter the crude p-iodoaniline with suction on a Buchner funnel, drain as completely as possible, and dry it in the air. Save the filtrate for the recovery of the iodine (1). Place the crude product in a 750 ml. round-bottomed flask fitted with a reflux double surface condenser add 325 ml. of light petroleum, b.p. 60-80°, and heat in a water bath maintained at 75-80°. Shake the flask frequently and after about 15 minutes, slowly decant the clear hot solution into a beaker set in a freezing mixture of ice and salt, and stir constantly. The p-iodoaniline crystallises almost immediately in almost colourless needles filter and dry the crystals in the air. Return the filtrate to the flask for use in a second extraction as before (2). The yield of p-iodoaniline, m.p. 62-63°, is 60 g. 

When the first edition of Chemistry of Petrochemical Processes was written, the intention was to introduce to the users a simplified approach to a diversified subject dealing with the chemistry and technology of various petroleum and petrochemical process. It reviewed the mechanisms of many reactions as well as the operational parameters (temperature, pressure, residence times, etc.) that directly effect products yields and composition. To enable the readers to follow the flow of the reactants and products, the processes were illustrated with simplified flow diagrams. 

In a dry, 1-1., two-necked flask, equipped with a mechanical stirrer and a reflux condenser fitted with a drying tube, are placed 17.8 g. (0.100 mole) of anthracene (Note 1), 27.2 g. (0.202 mole) of anhydrous cupric chloride (Note 2), and 500 ml. of carbon tetrachloride (Note 3). The reaction mixture is stirred and heated under reflux for 18-24 hours. The brown cupric chloride is gradually converted to white cuprous chloride, and hydrogen chloride is gradually evolved. At the end of the reaction the cuprous chloride is removed by filtration, and the carbon tetrachloride solution is passed through a 35-mm. chromatographic column filled with 200 g. of alumina (Note 4). The column is eluted with 400 ml. of carbon tetrachloride. The combined eluates are evaporated to dryness to give 19-21 g. (89-99%) of 9-chloroanthracene as a lemon-yellow solid, m.p. 102-104° (Note 5). Crystallization of the product from petroleum ether... 

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