Applications of Sulfuric Acid

Sulfuric acid being a key product in the chemical industry has many applications. Worldwide 65% is utilized in the manufacture of phosphorus and nitrogen fertilizers, whereas in Western Europe only 31% is so utilized. In the Federal Republic of Germany ca. 90% of the sulfuric acid produced is utilized in the chemical industry. 

In the petrochemical industry sulfuric acid is utilized, for example, in the alkylation of isoalkanes with alkenes, in the chemical industry in the manufacture inorganic chemicals (e.g. hydrofluoric acid, chromic acid, aluminum sulfate) and organic products (e.g. dyes, explosives, isocyanates, soaps, detergents, fibers and pharmaceuticals). Sulfuric acid is also utilized in the manufacture of titanium oxide pigments, uranium and copper extraction, in steel pickling and in batteries. 

Applications of H2SO4 in the Federal Republic of Germany and in Western Europe in 1993 (%)  

Desulfurization of power station furnace gases is industrially possible using wet and dry purification processes 

A number of processes are used for the manufacture of 100% sulfur dioxide  

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Application of sulfuric acid as the catalyst is considered more practical for esterification because of its higher boiling point, its incompatibility with benzene, and the stability of nitroacetic acid in the reaction mixture that allows the omission of the final neutralization step. 

In cases in which the space charge across the electrical field was insufficiently intense for proper charge buildup, it was found that ammonia injection improved the capturability of the fly ash (14)- Other studies confirmed the applicability of sulfuric acid, ammonium sulfate and ammonium bisulfate as useful conditioners (15). 

An interesting application of sulfuric acid cyclization was reported 194 in which /3-benzylglutaric acid (LXXXHI) was cyclized to the keto acid LXXXIV by the action of concentrated sulfuric acid at room temperature. The yield of crude material was 88%. This seems to be a... 

Another type of analytical application of sulfuric acid oxidation has been developed recently, based on the intense fluorescence which appears when the sulfuric solutions containing oxidized pheno-thiazine derivatives are diluted with dimethyl sulfoxide. It has been shown that concentrations as low as 0.01 /xg/ml may be detected this way and that substituents in position 2 decrease the intensity of the fluorescence to a greater extent than side chains at position 10.1 1... 

The large volume and wide application of sulfuric acid in the chemical and petroleum refining industries has meant that the per capita production of sulfuric acid is one of the better indicators of the industrial development of a country. Less circumstantial anomalies occur in a listing of annual sulfuric acid production (Table 9.5), a chemical product, than occurs with per capita sulfur production, an extractive product. Thus, average sulfuric acid production levels of the developed countries are from 50 up to 200 kg per capita per year compared to less than 5 kg per capita for Third World countries. 

The use of sulfuric acid began similarly in the 1900s in France, and shortly afterwards in Germany (Rabate, 1911 Gelpke, 1914). The selective application of sulfuric acid and sulfates has been described by Morettini (1915) and Korsmo (1930). 

In modern times, resist stripping for FEOL layers is typically accomplished with first the application of sulfuric acid and hydrogen peroxide mixture (SPM) solution, followed by the application of ammonium hydroxide and hydrogen peroxide mixture (APM) solution. This combination of solutions is able to strip off almost every kind of resist, except those that have been used in implant processes or have been hard baked or modified by plasma gases during dry etching... 

Fig. 3 The densitograms of bile acids investigated (C, cholic acid GC, glycocholic acid GLC, glycolithocholic acid DC, deoxycholic acid CDC, chenodeoxycholic acid GDC, glyco-deoxycholic acid LC, lithocholic acid) at wavelengths 380, 400, 420, 440, and 460 nm after their separation using a n-hex-ane-ethyl acetate-methanol-acetic acid, 20 20 5 2 (v/v/v/v) as mobile phase and after the application of sulfuric acid in methanol (1 19, v/v the plate was immersed in dipping the solution of sulfuric acid for 15 sec, and it was then heated to 90°C for 20 min) as visualizing reagent.

Table 5 Absorption maximum of investigated bile acids after separation on silica gel 60 and after the application of sulfuric acid and phosphomolybdic acid as visualizing reagents.

Bronsted Acids. Sulfuric acid (H2SO4) is an inexpensive, easy to handle protic acid used widely as catalyst in hydrolysis, hydration and dehydration, elimination, substitution, and rearrangements. It also catalyzes aromatic electrophilic substitutions mostly Friedel-Crafts acylations and alkylations (22). A very important application of sulfuric acid is its use in commercial isoalkane-alkene alkylation technologies. These commercial processes are still based on the use of sulfuric acid (and hydrogen fluoride) catalysts (23). 

The most important application of sulfuric acid is in the preparation of phosphoric acid, by the so-called wet acid process. This produces phosphoric acid from the reaction of dilute sulfuric acid with mineral phosphate. 

These alloys have extensive applications in sulfuric acid systems. Because of their increased nickefand molybdenum contents they are more tolerant of chloride-ion contamination than standard stainless steels. The nickel content decreases the risk of stress-corrosion cracking molybdenum improves resistance to crevice corrosion and pitting. 

Where resorcinol adhesives are not suitable, resins can be prepared from modified resorcinol [128], Characteristic of these types of resins arc those used for tyre cord adhesives, in which a pure resorcinol-formaldehyde resin is used, or alternatively, alkyl resorcinol or oil-soluble resins suitable for rubber compounding are obtained by prereaction of resorcinol with fatty acids in the presence of sulfuric acid at high temperature followed by reaction with formaldehyde. Worldwide more than 90% of resorcinol adhesives are used as cold-setting wood adhesives. The other most notable application is as tyre cord adhesives, which constitutes less than 5% of the total use. 

We shall apply this scheme to a series of types of calculations to show its general applicability. The calculations are all connected with the manufacture of sulfuric acid, H2S04, one of the most important commercial chemicals. 

As esters of sulfuric acid, the hydrophilic group of alcohol sulfates and alcohol ether sulfates is the sulfate ion, which is linked to the hydrophobic tail through a C-O-S bond. This bond gives the molecule a relative instability as this linkage is prone to hydrolysis in acidic media. This establishes a basic difference from other key anionic surfactants such as alkyl and alkylbenzene-sulfonates, which have a C-S bond, completely stable in all normal conditions of use. The chemical structure of these sulfate molecules partially limits their conditions of use and their application areas but nevertheless they are found undoubtedly in the widest range of application types among anionic surfactants. 

The sulfuric acid concentration should be at that required for the particular product application. Sources of sulfuric acid in LAS are as follows ... 

Ammonia synthesis is the second largest chemical process, after the production of sulfuric acid (see also Chapter 1). It accounts for about 1 % of the total human-related energy consumption. Roughly 80 % of the ammonia produced is used for fertilizers (either as liquid ammonia or as more easily handled salts such as ammonium nitrate, ammonium phosphate, etc.) and, as such, ammonia synthesis is indispensable for our society. Other applications of ammonia are nitrogen-containing... 

Replacing some of the nickel with iron produces a family of alltws with intermediate corrosion resistance between stainless steels and the Ni-Cr-Mo alloys. Alloys such as Incoloy 825 and Hastelloy G-3 and G-30 are in this family. Incoloy 825 has 40 percent Ni, 21 percent Cr, 3 percent Mo, and 2.25 percent Cu. Hastelloy G-3 contains 44 percent Ni, 22 percent Cr, 6.5 percent Mo, and 0.05 percent C maximum. These alloys have extensive applications in sulfuric acid systems. Because of their increased nickel and molybdenum contents they are more tolerant of chloride-ion contamination than are standard stainless steels. The nickel content decreases the risk of stress-corrosion cracking molybdenum improves resistance to crevice corrosion and pitting. Many of the nickel-based alloys are proprietary and are coverecf by the following specifications ... 

The application of solvent extraction to copper recovery has been a major growth area since the last review of this series.11,13 Almost 30% of world production in 2000 involved the use of sulfuric acid heap leaching, solvent extraction, and electrowinning, far exceeding earlier predictions.136... 

Two of the methods (ASTM D2007, D4124) use adsorbents to fractionate the deasphaltened oil, but the third method (ASTM D2006) advocates the use of various grades of sulfuric acid to separate the material into compound types. Caution is advised in the application of this method since the method does not work well with all feedstocks. For example, when the sulfuric acid method (ASTM D2006) is applied to the separation of heavy feedstocks, complex emulsions can be produced. 

Calcium sulfate is formed as a byproduct in industrial processes such as flue gas desulfurization and the production of zinc, fluoride, organic acids and phosphoric acid, in amounts of many million tons per year. In this study the attention is focussed on calcium sulfate from the production of phosphoric acid for fertilizer applications. It is precipitated, from solution after digestion of phosphate ore by addition of sulfuric acid according to [1] ... 

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