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Sulfuric acid and treatment

Bischloromethyl ether has been prepared by saturation of formalin with dry hydrogen chloride by the reaction of paraformaldehyde with phosphorus trichloride or phosphorus oxychloride, by solution of paraformaldehyde in concentrated sulfuric acid and treatment with ammonium chloride or dry hydrogen chloride, and by suspension of paraformaldehyde in seventy or eighty percent sulfuric acid and treatment with chlorosulfonic acid. It is formed together with the asymmetrical isomer when methyl ether is chlorinated and when paraformaldehyde is treated with chlorosulfonic acid. The present method has been published. ... [Pg.2]

However, the method is no longer satisfactorily applicable to synthesis of higher polysilane derivatives because extensive cleavage of the silicon-silicon bond occurs and a mixture of isomeric halopolysilane derivatives that are inseparable by distillation is formed. For example, the reaction of decamethyltetrasilane with sulfuric acid and treatment with ammonium hydrogen fluoride leads to the formation of several fluoro derivatives of... [Pg.21]

Derivation (1) By reduction of p-nitrophenol with iron filings and hydrochloric acid (2) by electrolytic reduction of nitrobenzene in concentrated sulfuric acid and treatment with an alkali to free the base. Also available as the hydrochloride. [Pg.62]

Sulfated ash in lubricating oils in greases NF T 60-143 ISO 3987 ASTM D 874 NF T 60-144 ASTM D 128 Weight of residue after treatment of the ash by sulfuric acid and calcination As above... [Pg.450]

As mentioned in Section IX-2A, binary systems are more complicated since the composition of the nuclei differ from that of the bulk. In the case of sulfuric acid and water vapor mixtures only some 10 ° molecules of sulfuric acid are needed for water oplet nucleation that may occur at less than 100% relative humidity [38]. A rather different effect is that of passivation of water nuclei by long-chain alcohols [66] (which would inhibit condensation note Section IV-6). A recent theoretical treatment by Bar-Ziv and Safran [67] of the effect of surface active monolayers, such as alcohols, on surface nucleation of ice shows the link between the inhibition of subcooling (enhanced nucleation) and the strength of the interaction between the monolayer and water. [Pg.338]

Adberabibty of the film may be enhanced by its treatment with flame, electric discharge, boron trifluoride gas, activated gas plasma, dichromate sulfuric acid, and a solution of alkab metal ia Hquid ammonia (84—87). A coating of polyurethane, an alkyl polymethacrylate, or a chlotinated adhesive can be apphed to PVF surfaces to enhance adhesion (80,88,89). [Pg.381]

The typical SEA process uses a manganese catalyst with a potassium promoter (for solubilization) in a batch reactor. A manganese catalyst increases the relative rate of attack on carbonyl intermediates. Low conversions are followed by recovery and recycle of complex intermediate streams. Acid recovery and purification involve extraction with caustic and heat treatment to further decrease small amounts of impurities (particularly carbonyls). The fatty acids are recovered by freeing with sulfuric acid and, hence, sodium sulfate is a by-product. [Pg.344]

Industrial Wastewater Treatment. Industrial wastewaters require different treatments depending on their sources. Plating waste contains toxic metals that are precipitated and insolubiHzed with lime (see Electroplating). Iron and other heavy metals are also precipitated from waste-pidde Hquor, which requires acid neutralization. Akin to pickle Hquor is the concentrated sulfuric acid waste, high in iron, that accumulates in smokeless powder ordinance and chemical plants. Lime is also useful in clarifying wastes from textile dyeworks and paper pulp mills and a wide variety of other wastes. Effluents from active and abandoned coal mines also have a high sulfuric acid and iron oxide content because of the presence of pyrite in coal. [Pg.178]

After epoxidation, propylene oxide, excess propylene, and propane are distilled overhead. Propane is purged from the process propylene is recycled to the epoxidation reactor. The bottoms Hquid is treated with a base, such as sodium hydroxide, to neutralize the acids. Acids in this stream cause dehydration of the 1-phenylethanol to styrene. The styrene readily polymerizes under these conditions (177—179). Neutralization, along with water washing, allows phase separation such that the salts and molybdenum catalyst remain in the aqueous phase (179). Dissolved organics in the aqueous phase ate further recovered by treatment with sulfuric acid and phase separation. The organic phase is then distilled to recover 1-phenylethanol overhead. The heavy bottoms are burned for fuel (180,181). [Pg.140]

Although tetrafluorosilane can be readily produced by the action of hydrogen fluoride on sihca, its production is a by-product of HF production by the reaction of fluorospar and sulfuric acid and as a by-product from phosphate fertilizer production by the treatment of fluoroapatite with sulfuric acid (171). The most significant U.S. production is by IMC-Agrico at Uncle Sam, Louisiana. [Pg.32]

Several common acid treatments for sample decomposition include the use of concentrated nitric acid, aqua regia, nitric—sulfuric acids, and nitric perchloric acids. Perchloric acid is an effective oxidant, but its use is ha2ardous and requkes great care. Addition of potassium chlorate with nitric acid also assists in dissolving any carbonaceous matter. [Pg.387]

Other Arsenic Hydrides. Diarsine [15942-63-9] AS2H4, occurs as a by-product in the preparation of arsine by treatment of a magnesium aluminum arsenide alloy with dilute sulfuric acid and also may be prepared by passing arsine at low pressure through an ozonizer-type discharge tube (19). Diarsine is fairly stable as a gas but quite unstable (above — 100°C) in condensed phases. The for diarsine is +117 4 kJ/mol (28 1 kcal/mol) and... [Pg.333]

The equihbrium shown in equation 3 normally ties far to the left. Usually the water formed is removed by azeotropic distillation with excess alcohol or a suitable azeotroping solvent such as benzene, toluene, or various petroleum distillate fractions. The procedure used depends on the specific ester desired. Preparation of methyl borate and ethyl borate is compHcated by the formation of low boiling azeotropes (Table 1) which are the lowest boiling constituents in these systems. Consequently, the ester—alcohol azeotrope must be prepared and then separated in another step. Some of the methods that have been used to separate methyl borate from the azeotrope are extraction with sulfuric acid and distillation of the enriched phase (18), treatment with calcium chloride or lithium chloride (19,20), washing with a hydrocarbon and distillation (21), fractional distillation at 709 kPa (7 atmospheres) (22), and addition of a third component that will form a low boiling methanol azeotrope (23). [Pg.214]

Treatment with sulfuric acid and fractional distillation are the main methods used to purify bromine. It is especially important to reduce the water content to less than 30 ppm to prevent corrosion of metal transportation and storage containers. [Pg.285]

Note 1. An alternative procedure proceeds by oxidation of the 3/5-hydroxy group with chromic acid-sulfuric acid and subsequent elimination of hydrogen chloride by treatment of the intermediate chloroketone with potassium acetate in methanol. Good overall yields are obtained with this reaction sequence in the androstane series. [Pg.280]

Perfluorohexamethylbenzene is converted to perfluoropentamethylbenzoic acid by sequential treatment with sodium methoxide, then concentrated sulfuric acid, and finally fuming sulfuric acid [37] (equation 38). The intermediate methyl ortho ester and methyl ester of the acid can be isolated... [Pg.433]

Several other research teams used the Paal-Knorr condensation to prepare 2,5-disubstituted furans that were investigated as potential enzyme inhibitors. Nagai produced furan 17 via treatment of dione 16 with sulfuric acid and subsequently examined the activity of 17 toward a retenoic acid receptor. Perrier discovered that furan 19, derived from dione 18, is a potent PDE4 inhibitor and may have anti-inflammatory activity. ... [Pg.170]

Diaryl bisfurans are available from two sequential Paal-Knorr reactions of tetraketones. For example, Barba converted 46 into 3,3"-bis-2,5-diphenylfuran (47) in good yield upon treatment with sulfuric acid and acetic anhydride. ... [Pg.173]

Ethyl benzoylacetate has been prepared by the condensation (by means of sodium ethylate) of ethyl acetate with ethyl benzoate,1 acetophenone with ethyl carbonate,2 and acetophenone with ethyl oxalate, with subsequent heating 3 by treatment of ethyl phenylpropiolate4 or a-bromocinnamic acid 5 with concentrated sulfuric acid, and of ethyl diazoacetate with benzalde-hyde 6 by the condensation of benzene with the monoethyl ester of malonyl monoacid chloride and aluminum chloride,7 of benzoyl chloride with the product of the reaction of magnesium and ethyl chloroacetate in ether,8 of alcohol on benzoylacetimino ethyl... [Pg.34]

The important observation from the data in Table 3 is that NC samples subjected to acid bod followed by tetrahydrofuran (THF)-benzene treatment yielded essentially the same sulfate contents as samples subjected to THF-benzene treatment alone. From this the authors interpret that sulfate contents from THF-benzene treatments actually represent absolute values of the difficult-to-remove sulfate which may very well be true sulfate ester . It is also tentatively concluded that approximately 90% of the original sulfate content in unstabilized NC is readily removable sulfuric acid with the remainder the more difficult-to-remove sulfate ester. Dilute acid boil treatment of NC for 56 hours does not eliminate all of the free sulfuric acid and leaves the difficult-to-remove sulfate practically unchanged... [Pg.401]

Freund (Ref 2) nitrated a fraction of Galician petroleum (from Borislaw), bp 270—380°, d 0.858—0.870g/cc (previously purified by treatment with 1% coned sulfuric acid), and obtained a red-brown powder with a N content of about 6.8%... [Pg.698]

Alkylation of protonated nitrogen heterocycles (e.g., pyridines, quinolines) can be accomplished by treatment with a carboxylic acid, silver nitrate, sulfuric acid, and ammonium peroxydisulfate. The R group can be primary, secondary, or tertiary. The attacking species is R% formed by " ... [Pg.933]

Common pollutants in a titanium dioxide plant include heavy metals, titanium dioxide, sulfur trioxide, sulfur dioxide, sodium sulfate, sulfuric acid, and unreacted iron. Most of the metals are removed by alkaline precipitation as metallic hydroxides, carbonates, and sulfides. The resulting solution is subjected to flotation, settling, filtration, and centrifugation to treat the wastewater to acceptable standards. In the sulfate process, the wastewater is sent to the treatment pond, where most of the heavy metals are precipitated. The precipitate is washed and filtered to produce pure gypsum crystals. All other streams of wastewater are treated in similar ponds with calcium sulfate before being neutralized with calcium carbonate in a reactor. The effluent from the reactor is sent to clarifiers and the solid in the underflow is filtered and concentrated. The clarifier overflow is mixed with other process wastewaters and is then neutralized before discharge. [Pg.949]


See other pages where Sulfuric acid and treatment is mentioned: [Pg.497]    [Pg.157]    [Pg.497]    [Pg.157]    [Pg.389]    [Pg.297]    [Pg.335]    [Pg.345]    [Pg.572]    [Pg.482]    [Pg.87]    [Pg.321]    [Pg.50]    [Pg.145]    [Pg.330]    [Pg.566]    [Pg.480]    [Pg.1516]    [Pg.273]    [Pg.1534]    [Pg.68]    [Pg.769]    [Pg.93]    [Pg.254]    [Pg.67]   
See also in sourсe #XX -- [ Pg.289 , Pg.290 , Pg.293 , Pg.294 , Pg.295 , Pg.296 , Pg.330 , Pg.331 , Pg.338 , Pg.346 , Pg.363 , Pg.871 , Pg.872 ]




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