Organic petrochemical industry

Sodium nitrate is also used in formulations of heat-transfer salts for he at-treatment baths for alloys and metals, mbber vulcanization, and petrochemical industries. A mixture of sodium nitrate and potassium nitrate is used to capture solar energy (qv) to transform it into electrical energy. The potential of sodium nitrate in the field of solar salts depends on the commercial development of this process. Other uses of sodium nitrate include water (qv) treatment, ice melting, adhesives (qv), cleaning compounds, pyrotechnics, curing bacons and meats (see Food additives), organics nitration, certain types of pharmaceutical production, refining of some alloys, recovery of lead, and production of uranium. 

The pattern of commercial production of 1,3-butadiene parallels the overall development of the petrochemical industry. Since its discovery via pyrolysis of various organic materials, butadiene has been manufactured from acetylene as weU as ethanol, both via butanediols (1,3- and 1,4-) as intermediates (see Acetylene-DERIVED chemicals). On a global basis, the importance of these processes has decreased substantially because of the increasing production of butadiene from petroleum sources. China and India stiU convert ethanol to butadiene using the two-step process while Poland and the former USSR use a one-step process (229,230). In the past butadiene also was produced by the dehydrogenation of / -butane and oxydehydrogenation of / -butenes. However, butadiene is now primarily produced as a by-product in the steam cracking of hydrocarbon streams to produce ethylene. Except under market dislocation situations, butadiene is almost exclusively manufactured by this process in the United States, Western Europe, and Japan. 

In spite of all these problems and difficulties, tubular reactors are the most important equipment for organic intermediate production in the petrochemicals industry. 

By-product HCl from the heavy organic-chemicals industry (p, 798) now accounts for over 90% of the HCl produced in the USA, Where such petrochemical industries are less extensive this source of HCl becomes correspondingly smaller. The crude HCl so produced may be contaminated with unreacted CI2, organics, chloro-organics or entrained solids (catalyst supports, etc,), all of which must be removed. 

Corrosion reactions in aggressive organic solvents are becoming a more frequent occurrence owing to developments in the chemical and petrochemical industries, and these reactions can lead to the deterioration of the metal and to undesirable changes in the solvent. This aspect of corrosion has recently been the subject of an extensive review by Heitz who has considered the mechanisms of the reactions, the similarities between corrt ion in organic solvents and in aqueous solutions, the methods of study and the occurrence of the phenomenon in industrial processes. 

Fortunately, we have a different set of carbon starting materials available to us, derived from nature but inaccessible to her hydrocarbons, which are more advanced than carbon dioxide. Most come from the oil left for us by prehistoric lifeforms. The petrochemical industry cracks it into smaller unsaturated blocks containing at most eight carbon atoms, from which almost 90% (by weight) of all useful synthetic organics are made (Scheme 12.2) [4],... 

All of the above high-volume organic chemicals are obtained from petroleum or natural gas. This is why the modern organic chemical industry is frequently referred to as the petrochemical industry. The high-volume status of some of these compounds is due to their use to make others lower on the list. For example, ethylene is used to make ethylene dichloride, which, in turn, is used to make vinyl chloride. Ethyl benzene, made from benzene and ethylene, is used to make styrene. Methyl r-butyl ether is made from methanol and butylene, a captive intermediate for which production data is not available. 

Petrochemical recovered oil. Organic chemical manufacturing facilities sometimes recover oil from their organic chemical industry operations. U.S. EPA excluded petrochemical recovered oil from the definition of solid waste when the facility inserts the material into the petroleum-refining process of an associated or adjacent petroleum refinery. Only petrochemical recovered oil that is hazardous because it exhibits the characteristic of ignitability or exhibits the toxicity characteristic for benzene (or both) is eligible for the exclusion. 

Zeolites are the main catalyst in the petrochemical industry. The importance of these aluminosilicates is due to their capacity to promote many important reactions. By analogy with superacid media (1), carbocations are believed to be key intermediates in these reactions. However, simple carbocationic species are seldom observed on the zeolite surface as persistent intermediates within the time-scale of spectroscopic techniques. Indeed, only some conjugated cyclic carbocations were observed as long living species, but covalent intermediates, namely alkyl-aluminumsilyl oxonium ions (2) (scheme 1), where the organic moiety is bonded to the zeolite structure, are usually thermodynamically more stable than the free carbocations (3,4). 

Disposal of solid wastes is a significant problem for the petrochemical industry. Waste solids include water treatment sludge, ashes, fly ash and incinerator residue, plastics, ferrous and nonferrous metals, catalysts, organic chemicals, inorganic chemicals, filter cakes, and viscous solids. 

The first of these, the solventless option, is the best established, and is central to the petrochemical industry, the greenest chemical sector. The second, to use water as the solvent, can be an ideal approach,but suffers from the difficulty of dissolving many organic compounds in water, undemonstrated scale-up, and the cost of the cleanup of organic contaminated water. Supercritical fluids represent a... 

The move to petroleum as a raw materials source for the organic chemical industry began during the 1940s. Petrochemicals, as they are called, are now used to create thousands of useful industrial chemicals. The rate of commercial introduction of new chemicals shot up rapidly after World War II. 

The double bond difference between the olefins and the paraffins is the quintessential difference between the petrochemicals and petroleum products— the petrochemicals industry depends much more on the chemical reactivity of the double-bonded molecules. While paraffins can be manipulated in refineries by separation or reshaping, olefins in a petrochemical plant are usually reacted with other organic compounds or another kind of atom or compound such as oxygen, chlorine, water, ammonia, or more of itself. The results are more complicated compounds useful in an increasing number of chemical applications. More on this in later chapters. 

The separation of organic mixtures into groups of components of similar chemical type was one of the earliest applications of solvent extraction. In this chapter the term solvent is used to define the extractant phase that may contain either an extractant in a diluent or an organic compound that can itself act as an extractant. Using this technique, a solvent that preferentially dissolves aromatic compounds can be used to remove aromatics from kerosene to produce a better quality fuel. In the same way, solvent extraction can be used to produce high-purity aromatic extracts from catalytic reformates, aromatics that are essentially raw materials in the production of products such as polystyrene, nylon, and Terylene. These features have made solvent extraction a standard technique in the oil-refining and petrochemical industries. The extraction of organic compounds, however, is not confined to these industries. Other examples in this chapter include the production of pharmaceuticals and environmental processes. 

Oil and Petrochemical Industries as Sources of Hazardous Organic Wastes... 

The need to conserve raw materials and enhance the yield of high-value products has led the petrochemical industry to rely increasingly on processes that involve catalytic selective oxidation. In turn, this reliance has led to the emergence of important new technologies in the past decade—processes that use selective catalytic oxidation now generate almost a quarter of all organic chemicals produced worldwide. 

Other processes are combined with fractional distillation to obtain the multitude of chemicals used in the petrochemical industry. Cracking is a process where large organic molecules are broken up into smaller molecules. Thermal cracking involves the use of heat and pressure. Catalytic cracking employs various catalysts to reduce the amount of heat and pressure required during the cracking process. All lation is a process... 

Another large use of normal butenes in the petrochemical industry is in the production of 1,3-butadiene (CH2 = CH = CH = CH2). In the process, a mixture of n-butenes, air, and steam is passed over a catalyst at a temperature of 500°C to 600°C. Butadiene is used extensively to produce synthetic rubbers (see Isoprene) in polymerization reactions. The greatest use of butadiene is for styrene-butadiene rubber, which contains about a 3 1 ratio of butadiene to styrene. Butadiene is also used as a chemical intermediate to produce other synthetic organics such as chloroprene, for adhesives, resins, and a variety of polymers. 

Trickle-bed reactors usually consist of a fixed bed of catalyst particles, contacted by a gas liquid two-phase flow, with co-current downflow as the most common mode of operation. Such reactors are particularly important in the petroleum industry, where they are used primarily for hydrocracking, hydrodesulfurization, and hydrodenitrogenation other commercial applications are found in the petrochemical industry, involving mainly hydrogenation and oxidation of organic compounds. Two important quantities used to characterize a trickle-bed reactor are... 

Of the approximately 40 million tons (36 million metric tons) of sulfuric acid manufactured in the United States per year, about 90% is used in the production of fertilizers and other inorganic chemicals. Much of the remaining 10% of H2SO4 is used by the petroleum, petrochemical, and organic chemicals industries. Much of this latter acid is involved in recycling kinds of processes. As pollution regulations in various countries become more restrictive, spent acid may become a much more attractive raw material than has been the case in the past. 

Petroleum, the raw material of the petrochemical industry, consists mostly of members of the simplest family of organic compounds, the hydrocarbons, compounds containing only carbon and hydrogen. There is an enormous number of hydrocarbons because carbon can form an amazing variety of chains, rings, and networks of atoms, and can do so by forming single, double, and triple bonds. 

Because the petrochemical industry is based on hydrocarbons, especially alkenes, the selective oxidation of hydrocarbons to produce organic oxygenates occupies about 20% of total sales of current chemical industries. This is the second largest market after polymerization, which occupies about a 45% share. Selectively oxidized products, such as epoxides, ketones, aldehydes, alcohols and acids, are widely used to produce plastics, detergents, paints, cosmetics, and so on. Since it was found that supported Au catalysts can effectively catalyze gas-phase propylene epoxidation [121], the catalytic performance of Au catalysts in various selective oxidation reactions has been investigated extensively. In this section we focus mainly on the gas-phase selective oxidation of organic compounds. 

The MFI class of channel zeolites, of which ZSM-5 is a member, are of enormous importance in the petrochemicals industry because of their shape-selective adsorption and transformation properties. The most well-known example is the selective synthesis and diffusion of p-xylene through ZSM-5, in preference to the o- and m-isomers. Calcined zeolites such as ZSM-5 are able to carry out remarkable transformations upon normally unreactive organic molecules because of super-acid sites that exist... 

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