Sulphuric acid treatment

The sulphuric acid treatment removes high-boiling impurities which are not easily separated by distillation. 

The yield amounts to 34-38 g., and can be slightly increased by extracting the first mother liquor, from the sulphuric acid treatment, with ether. 

After the primary concentration process, the monazite is broken down either by the traditional sulphuric acid treatment or by the more recent caustic soda method. Several books [21,140,141] and reviews [142—144] give the useful details of the treatment of monazite. 

Sulphuric acid vs. caustic soda breakdown. —Although a greater variety of monazite sands can be processed by sulphuric acid treatment than by the... 

Fig. 1 Surface morphology of polysulphone after sulphuric acid treatment...

For copper, the relatively and unusually high content of I (about 160 mg kg ) had caused difficulties both in electrochemical analysis (e.g. complexation) and in spectrometric analysis (e.g. volatility of iodides in volatilisation step in ETAAS) measures had to be taken to remove or bind the iodide (e.g. by complexation, precipitation or sulphuric acid treatment). 

During this optimisation programme, samples of eel, fish oil, mussel and sewage sludge were prepared for intercomparison. Data from analysis of a crude eel extract and a refined (cleaned-up) sample were compared to test the variance associated with different methods of sample preparation. The clean-up methods included gel permeation chromatography, saponification, concentrated sulphuric acid treatment, alumina and silica-gel column chromatography. The differences in results of the within and between clean-up methods did not significantly influence the overall analytical variance after the appropriate optimisation. 

Lien and Zang [117] investigated the ehmination of MTBE and TAME with bifunctional aluminum. After 6 h a complete ehmination of MTBE with initial concentration of 35 mg/L was observed in the presence of oxygen. Without oxygen only 40% elimination was achieved, however, no reaction by-products were observed, indicating that the ehmination was only due to the sorption of MTBE onto the catalyst. Without bifunctional aluminum no reaction took place. The sulphuric acid treatment is decisive for the performance, since aluminum without sulfation only yielded 25% conversion of MTBE. 

In the detergent industry sulphonation processes with sulphuric acid, oleum and SO3-complexes are essentially of historical significance, and are not any longer used in developed countries. In the production of white oils, however, sulphonation with concentrated sulphuric acid and oleum is still used. The sulphuric acid treatment of selected petroleum fractions lead to petroleum sulphonates the sodium or ammonium salts of which are used in tertiary oil recovery, metallurgy, froth flotation and concrete industry, while the magnesium, calcium and barium salts are used as dopes in fuels and lubricants. The sulphonation with chlorosulphonic acid continue to remain useful in batch processes, typically on a relatively small scale ... 

M. Tomaszewska, Concentration of the extraction fluid from sulphuric acid treatment of phosphogypsum by membrane distillation, J. Membr. Sci. 78 (1993) 277-282. 

Numerous —SO3H groups are then introduced by the sulphuric acid treatment. 

Treatment of 2,3,4,6-tetra-O-methyl-0 ,j3-D-glucopyranose with 30% hydrogen peroxide in the presence of potassium hydroxide yields the products (2)-(7), thought to arise by decomposition of the hydroperoxide (8), Mechanistic schemes were proposed.The formation of reductic acid from methyl -D-ribo-hexosid-3-ulose by sulphuric acid treatment has been studied by -tracer... 

Semi-synthetic oils contain mineral oils of concentrations varying between io% and 50%. They therefore provide more lubrication than synthetic oils. To enable the mineral oil to blend with water and remain in a finely dispersed state requires the addition of emulsifiers (20-40%). These are often based on petroleum sulphonates, which are produced by the sulphuric-acid treatment of spindle oils to produce white oils and carboxylic acids. 

Reactions.—Condensation of thiet sulphone with 2 moles of halogeno-hydrazones, RC(Cl)=NNHPh, gives isoimidazoles (113). Cycloaddition of thiet sulphone to cyclopentadiene occurs with an exofendo ratio of 0.25. 2,4-Diphenylthiet dioxide is hydrolysed to dibenzyl sulphone with base, but rearranges to the isomeric sulphinate 3,5-diphenyl-1,2-oxathiolen 2-oxide with concentrated sulphuric acid. Treatment of 4-phenyl-2i/-thiet 1,1-dioxide with KOH in ethanol gives 3-ethoxy-2-phenylthietan 1,1 -dioxide. ... 

C. Determination of Absorbance after Sulphuric Acid Treatment... 

Cycle life data for (a) TANS9S series and (b) TANllS series of graphitic carbons heat-treated at 900°C and 1100°C respectively, with sulphuric acid treatment denoted by S followed by the duration of the treatment in hours. (Reprinted with permission from Carbon, 43, Y.J. Kim et al.. Effects of sulfuric acid treatment on the microstructure and electrochemical performance of a polyacrylonitrile (PAN)-based carbon anode, 2005,163-169, Copyright 2005, Elsevier.)... 

---