Benzene petroleum refining

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. 

First, points of release of benzene were identified petroleum refining and coke oven operations (production and extraction releases), use as a chemical intermediate (transportation, storage, use, and waste releases), use in gasoline (use-related release), and use in finished products (use-related release). Benzene also can be a contaminant of most of the derivatives made from it and its use as a solvent was substantial before health concerns arose. The complexity of the chemical systems dependent on benzene is shown in Figure 6. A list of potential releasing products appears in Table II. 

Penex-Plus A petroleum refining process that combines the Penex process with a process for hydrogenating benzene to cyclohexane. Developed by UOP for reducing the benzene content of gasoline first offered for license in 1991. 

Hydroprocessing, in petroleum refining, 18 654-657 Hydropulping, 10 535 Hydropyrolysis, coal liquefaction, 6 854 Hydroquinolines, 21 198-199 Hydroquinone (HQ) from benzene, 3 620 as a black-and-white chemical reducing agent, 19 205-206 in bleaching preparations, 7 847 clathrates, 14 160 dye releaser, 19 291-292 inclusion compounds in, 14 172, 174 intermediate used in oxidation hair dyes, 7 858t... 

Why start out with benzene The obvious answer is that benzene is one of the handRil of basic building blocks in the petrochemicals industry along with ethylene, propylene, and a few others. The more subde reason is that benzene, more than any of those other chemicals, comes from a broader b e- steel mill coking, petroleum refining, and olefins plants. For that reason, the benzene network, the sources and the uses, is more complex than any of the others. 

Benzene from coal coking started to become less important in the 1950s as the benzene market mushroomed considerably faster than the steel market, and the marginal supply of benzene came from petroleum refining. Coal-based benzene for the U.S. chemical industry dropped from nearly 100% in 1955 to 50% in the 1960s and less than 5% after the 1980s. Coal-based economies like South Africa and New Zealand sail rely considerably more on coal-derived benzene. 

Benzene is produced from petroleum refining, coal tar distillation, coal processing, and coal coking (quoted, Verschueren, 1983). A high-temperature coal tar contained benzene at an average concentration of 0.12 wt % (McNeil, 1983). 

Fuel oils are petroleum products that are used in many types of engines, lamps, heaters, furnaces, stoves, and as solvents. Fuel oils come from crude petroleum and are refined to meet specifications for each use. Fuel oils are mixtures of aliphatic (open chain and cyclic compounds that are similar to open chain compounds) and aromatic (benzene and compounds similar to benzene) petroleum hydrocarbons. In addition, they may contain small amounts of nitrogen, sulfur, and other elements as additives. The exact chemical composition (i.e., precise percentage of each constituent) of each of the fuel oils discussed in this profile may vary... 

A minor route, which now accounts for 2% of phenol, takes advantage of the usual surplus of toluene from petroleum refining. Oxidation with a number of reagents gives benzoic acid. Further oxidation to p-hydroxybenzoic acid and decarboxylation yields phenol. Here phenol competes with benzene manufacture, also made from toluene when the surplus is large. The last 2% of phenol comes from distillation of petroleum and coal gasification. 

ZSM-5 is a Mobil-proprietary, shape-selective zeolite which is used commercially in synthetic fuels (methanol-to-gasoline), petrochemicals (xylene isomerization, toluene disproportionation, benzene alkylation) and in petroleum refining (lube and... 

Cyclohexane. It can be prepared with high purity by distillation of a mixture of alkanes fi om petroleum refining or by reduction of benzene. 

As examples of vapors may be cited those of petroleum hydrocarbons in petroleum refining plants, vapors of solvents (such as alcohol, ether, acetone, carbon tetrachloride, carbon disulfide, etc used in plants manufg expls and propints) vapors of liquid expls (such as DNB, DNT, NG, NGc, DEGDN, etc), and vapors of liquids (such as benzene, toluene or xylene) used as primary materials in the manuf of expls such as TNB, TNT or TNX. Some solid expls such as TNT evolve, when in molten condition, explosive vapors... 

Xylenes are produced from the reformulation of naphthas during petroleum refining in a process that also produces benzene, toluene, and ethylbenzene. Collectively, these are... 

T he petroleum industry entered the field of aromatics production largely because the unprecedented demand for toluene for the manufacture of TNT at the outbreak of World War II in 1939 could not be met by other sources. As a result of its efforts, the industry supplied 75 to 85% of all the toluene which was nitrated for TNT production during the latter years of World War II. Since that time the petroleum refiners have remained in the field and at present they are major suppliers of toluene and xylenes. In Table I it is shown that in 1949 about 59% of the toluene and 84% of the xylenes produced in the United States were derived from petroleum sources. The petroleum industry has diversified its operations in the field of aromatics production until at present a variety of materials is offered. Table II presents a partial list of the commercially available aromatics, together with some of their uses. A number of other aromatics, such as methylethyl-benzene and trimethylbenzene, have been separated in small scale lots both as mixtures and as pure compounds. 

Benzene Chemical and rubber processing, petroleum refining Bone marrow... 

Much of the aromatic product obtained by catalytic re-forming is blended with other fractions from petroleum refining to give high-octane gasoline. The rest is separated into its component hydrocarbons, which then are utilized by the chemical industry for the production of chemicals derived from benzene, methylbenzene, and the dimethylbenzenes, as summarized in Figures 22-9 and 22-10,... 

Ethylbenzene was the first petrochemical to be produced by petroleum refiners in large quantities. It is made by the alkylation of benzene by ethylene. Aluminum chloride promoted with ethyl chloride was originally the predominant catalyst used for the reaction, but solid phosphoric acid has been used more recently and is becoming more popular. Some of the newer fluoride-type catalysts are expected to become quite popular. 

Cumene or isopropylbenzene, diisopropylbenzene, and secondary butyl-benzene, although produced in smaller quantities than some of the other petrochemical alkylates, are very important petroleum refining products. Cumene is further reacted by oxidation to form cumene hydroperoxide, which is converted to phenol and acetone it is produced by alkylating benzene with propylene catalyzed by either solid or liquid phosphoric acid. Secondary butylbenzene is made by alkylating benzene with normal butylene using the same catalysts. Diisopropylbenzene is made by reacting cumene with propylene over solid phosphoric acid or aluminum chloride catalyst. 

At the present time, the industrial production of benzene and its homologs is implemented by coal carbonization, dehydrocyclization of the usual paraffin hydrocarbons and dehydrogenation of cyclohexane hydrocarbons with catalytic reforming of directly distilled gasoline fractions. The petroleum refining industry is the main source for meeting the demand for benzene and its reserves can fully meet the increasing demand for this compound. 

By the early part of the twentieth century, pure grades of volatile hydrocarbon solvents such as benzene and hexane became available through progress in petroleum-refining methods. They were found to be very useful for the extraction of fragrant plants and plant materials. If the plant material extracted is rich in waxes (as is generally the case with flowers, stems, and leaves), these are also taken up in the extract. After careful removal of the volatile solvent by distillation, a waxy concrete remains behind. This is then washed with alcohol to separate the fragrance materials, which are soluble in alcohol, from the insoluble waxes. An absolute is then produced by the removal of the alcohol by distillation, usually under reduced pressure. Certain plant materials that contain no water, such as resins or dried leaves and mosses, may be extracted directly with alcohol. The extracts obtained—often sticky, viscous, and resiny—are called resinoids. 

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