Sulfuric acid industry development

The standard dissolution procedure for titanium oxides is the ammonium sulfate-sulfuric acid mixture developed by Rahm [24]. The most commonly used method in industry is based on the use of metallic aluminum as the reductant, and ferric ammonium sulfate as the titrant. The use of ferric ion as the reagent is preferred, since relatively few species will interfere with its reaction with reduced titanium solutions. 

Dimerization in concentrated sulfuric acid occurs mainly with those alkenes that form tertiary carbocations In some cases reaction conditions can be developed that favor the formation of higher molecular weight polymers Because these reactions proceed by way of carbocation intermediates the process is referred to as cationic polymerization We made special mention m Section 5 1 of the enormous volume of ethylene and propene production in the petrochemical industry The accompanying box summarizes the principal uses of these alkenes Most of the ethylene is converted to polyethylene, a high molecular weight polymer of ethylene Polyethylene cannot be prepared by cationic polymerization but is the simplest example of a polymer that is produced on a large scale by free radical polymerization... 

Israel Mining Industries developed a process in which hydrochloric acid, instead of sulfuric acid, was used as the acidulant (37). The acidulate contained dissolved calcium chloride which then was separated from the phosphoric acid by use of solvent extraction using a recyclable organic solvent. The process was operated commercially for a limited time, but the generation of HCl fumes was destmctive to production equipment. 

In 1973 the Semiconductor Equipment and Materials Institute (SEMI) held its first standards meeting. SEMI standards are voluntary consensus specifications developed by the producers, users, and general interest groups in the semiconductor (qv) industry. Examples of electronic chemicals are glacial acetic acid [64-19-7] acetone [67-64-17, ammonium fluoride [12125-01 -8] and ammonium hydroxide [1336-21 -6] (see Ammonium compounds), dichloromethane [75-09-2] (see Cm.OROCARBONSANDcm.OROHYDROCARBONs), hydrofluoric acid [7664-39-3] (see Eluorine compounds, inorganic), 30% hydrogen peroxide (qv) [7722-84-1] methanol (qv) [67-56-1] nitric acid (qv) [7697-37-2] 2-propanoI [67-63-0] (see Propyl alcohols), sulfuric acid [7664-93-9] tetrachloroethane [127-18-4] toluene (qv) [108-88-3] and xylenes (qv) (see also Electronic materials). 

Other developing or potential appHcations for lime are neutralization of tail gas from sulfuric acid plants, neutralization of waste hydrochloric and hydrofluoric acids and of nitrogen oxide (NO ) gases, scmbbing of stack gases from incinerators (qv), and of course, from small industrial coal-fired boilers. 

Sulfur [7704-34-9] S, a nonmetallic element, is the second element of Group 16 (VIA) of the Periodic Table, coming below oxygen and above selenium. In massive elemental form, sulfur is often referred to as brimstone. Sulfur is one of the most important taw materials of the chemical industry. It is of prime importance to the fertilizer industry (see Fertilizers) and its consumption is generally regarded as one of the best measures of a nation s industrial development and economic activity (see Sulfur compounds Sulfurremoval and recovery Sulfuric acid and sulfur trioxide). 

Specifications for sulfuric acid vary rather widely. Exceptions include the federal specifications for "Sulfuric Acid, Technical" and "Sulfuric Acid, Electrolyte (for storage batteries)" and the Food Chemicals Codex specification for sulfuric acid, frequentiy called food-grade acid (although industrywide, "food-grade" is nonspecific). Very Httie has been done to estabUsh industry-wide analytical standards in the United States, except for development of the ASTM analytical methods, designated as E223-88 and summarized in Table 12. 

Most current industrial vitamin C production is based on the efficient second synthesis developed by Reichstein and Grbssner in 1934 (15). Various attempts to develop a superior, more economical L-ascorbic acid process have been reported since 1934. These approaches, which have met with htde success, ate summarized in Crawford s comprehensive review (46). Currently, all chemical syntheses of vitamin C involve modifications of the Reichstein and Grbssner approach (Fig. 5). In the first step, D-glucose (4) is catalytically (Ni-catalyst) hydrogenated to D-sorbitol (20). Oxidation to L-sotbose (21) occurs microhiologicaRy with The isolated L-sotbose is reacted with acetone and sulfuric acid to yield 2,3 4,6 diacetone-L-sorbose,... 

A.sahi Chemical EHD Processes. In the late 1960s, Asahi Chemical Industries in Japan developed an alternative electrolyte system for the electroreductive coupling of acrylonitrile. The catholyte in the Asahi divided cell process consisted of an emulsion of acrylonitrile and electrolysis products in a 10% aqueous solution of tetraethyl ammonium sulfate. The concentration of acrylonitrile in the aqueous phase for the original Monsanto process was 15—20 wt %, but the Asahi process uses only about 2 wt %. Asahi claims simpler separation and purification of the adiponitrile from the catholyte. A cation-exchange membrane is employed with dilute sulfuric acid in the anode compartment. The cathode is lead containing 6% antimony, and the anode is the same alloy but also contains 0.7% silver (45). The current efficiency is of 88—89%, with an adiponitrile selectivity of 91%. This process, started by Asahi in 1971, at Nobeoka City, Japan, is also operated by the RhcJ)ne Poulenc subsidiary, Rhodia, in Bra2il under Hcense from Asahi. 

There are two main processes for the synthesis of ethyl alcohol from ethylene. The eadiest to be developed (in 1930 by Union Carbide Corp.) was the indirect hydration process, variously called the strong sulfuric acid—ethylene process, the ethyl sulfate process, the esterification—hydrolysis process, or the sulfation—hydrolysis process. This process is stiU in use in Russia. The other synthesis process, designed to eliminate the use of sulfuric acid and which, since the early 1970s, has completely supplanted the old sulfuric acid process in the United States, is the direct hydration process. This process, the catalytic vapor-phase hydration of ethylene, is now practiced by only three U.S. companies Union Carbide Corp. (UCC), Quantum Chemical Corp., and Eastman Chemical Co. (a Division of Eastman Kodak Co.). UCC imports cmde industrial ethanol, CIE, from SADAF (the joint venture of SABIC and Pecten [Shell]) in Saudi Arabia, and refines it to industrial grade. 

Because calcium sulfide contained in the black ash had a highly unpleasant odor, methods were developed to remove the odor by recovering the sulfur, therein providing at least part of the raw-material for the sulfuric acid required in the first part of the process. Thus, the Leblanc prtKcss demonstrated, at the very beginning, the typical ability of the chemical industry to develop new processes and new products, and often in so doing to turn a liability into an asset. 

Phenylhydroxylamine rearranges in sulfuric acid to give mainly p-aminophenol. Industrial routes to this compound have been developed in which phenylhydroxylamine, formed by hydrogenation of nitrobenzene in sulfuric acid over platinum-on-carbon, is rearranged as it is formed. Conditions are adjusted so that the rate of rearran ment is high relative to the rate of hydrogenation of hydroxylamine to aniline (15,17,86). An easy way to obtain a favorable rate ratio is to carry out the reduction with about 1% DMSO present in the sulfuric acid (79,81). 

Many millions of tons of sulfuric acid, H2S04, are produced every year. Its uses are so wide that the amount consumed per year by a country can be taken as a crude index of the technological development of that country. Two manufacturing processes have widespread industrial importance and both will be described. These processes are so highly perfected that the cost of this useful chemical is only about S22.00 per ton ... 

NaC103 + NaCl + H2S04 = C102 + 1/2C12 + Na2S04 + H20 Developed by W. H. Rapson at the Electric Reduction Company of Canada, now Erco Industries, United States. Erco R-3 uses chloride in sulfuric acid as the reductant Erco R-3H uses mixed hydrochloric and sulfuric acids and Erco R-5 uses chloride in hydrochloric acid. 

HAL [Hot acid leaching] A process for purifying silica sand or zircon by leaching out surface iron compounds with hot sulfuric acid. Derived from an earlier process, invented in 1955 by British Industrial Sand, in which silica sand was treated with hot, gaseous hydrogen chloride. The process for cleaning zircon sand was developed jointly by Hepworth Minerals Chemicals, UK, and Metallurgical Services Pty, Australia, in 1991. 

Direct production of benzoquinone (BQ) from benzene is one of the targets in industrial chemistry. Considerable efforts have been made to develop the electrochemical oxidation of benzene to p-benzoquinone to the industrial scale thus forming a basis for a new hydroquinone process [40]. Benzene in aqueous emulsions containing sulfuric acid (1 1 mixture of benzene and 10% aqueous H2S04) forms, at the anode, p-benzoquinone which can be reduced cathodically to yield hydroquinone in a paired synthesis. A divided cell with Pb02 anodes is used. 

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