Alkaline treatments

Adducts from various quaternary salts have been isolated, in reactions with aldehydes, a-ketoaldehydes, dialkylacylphosphonates and dialkyl-phosphonates, isocyanates, isothiocyanates, and so forth (Scheme 15) (36). The ylid (11) resulting from removal of a Cj proton from 3.4-dimethyl-S-p-hydroxyethylthiazolium iodide by NEtj in DMF gives with phenylisothiocyanate the stable dipolar adduct (12) that has been identified by its NMR spectrum and reactional product, such as acid addition and thiazolidine obtention via NaBH4 reduction (Scheme 16) (35). It must be mentioned that the adduct issued from di-p-tolylcarbodiimide is separated in its halohydrogenated form. An alkaline treatment occasions an easy ring expansion into a 1,4-thiazine derivative (Scheme 17) (35). 

In 1902, Wheeler and Johnson (63) obtained 5-substituted rhodanines (54) by condensing substituted bromornalonic esters with postassium thiocyanate, then thiolacetic acid, the cydization resulting from an alkaline treatment. 

The nephrotoxic amino acid, lyskioalanine [18810-04-3] formed upon alkaline treatment of proteki, was reported ki 1964 (108). Its toxicity seems to be mitigated ki proteki ki that it is not released by normal digestion (109). Naturally occurring new amino acids, which can be classified as protekiaceous or non-protekiaceous, can, as ki the case of those from some legumes, show a remarkable toxicity (110). Eor the details of amino acid toxicity, see reference 6. Enzyme inhibition by amino acids and thek derivatives have been reviewed (111). 

Extraction of proteia requires breaking the cell wall to release the cytoplasmic contents. This can be achieved by high speed ball or coUoid mills or by high pressure (50—60 Mpa) extmsion. Proteia is extracted by alkaline treatment followed by precipitation after enzymatic hydrolysis of nucleic acids. Although the proteia can be spun iato fibers or texturized, such products are more expensive than those derived from soybean and there is no market for them. 

Analyses of a catalyst used ia a process involving cloaning products and pigments and achieving a hydrocarbon destmction capacity of only 13% showed deposition of P, Sn, Pb, and Na contaminants (20). Initial acid treatment iacreased the hydrocarbon destmction capacity from 13 to 63%. Alkaline treatment iacreased the capacity to 90% of that aew. 

Other acid-catalyzed exchanges have been reported with cholest-4-ene-3,6-dione (34) which is unstable to alkaline treatment and with 5a-androst-8(14)-en-lS-one which gives in addition to (35) a significant amount of de-conjugated side products. 

On the other hand, alkaline treatment of coumarin derivatives 108 did not lead to the expected cyclization products 107, but isomerization to the corresponding chromenes 109 took place instead (Scheme 17) (96JHC351). 

Acidic deacetylation of 129 followed by alkaline treatment of the intermediate 130 provided denitrocyclization product 131 in 51% overall yield (77KGS1271). A similar cyclized product was reported to be formed from 2-nitrobenzimidazole (132), which when treated with aziridine, instead of the corresponding aminoethyl derivative, provided 93% of benzimidazo[2,l-fo]imidazole 133 (Scheme 21) (82JMC1342). 

Ciprofibrate (48), a more potent lipid-lowering agent clofibrate, is prepared from Simmons-Smith product by Sandmeyer replacement of the amino group by a hydroxyl via the diazonium salt. Phenol undergoes the Reimer-Thiemann like process common to these agents upon alkaline treatment with acetone and chloroform to complete the synthesis of ci profib-rate (48). 

Catalyzed sodium sulfite should be fed separately from other treatments and inhibitors (via a stainless steel injection quill) because the presence of other alkaline treatments causes the cobalt to precipitate as cobaltous hydroxide in the tank. 

It is important that the tube surfaces be kept clean to avoid the initiation of corrosion. Regular waterside inspections and, if necessary, chemical cleaning of high-pressure equipment is recommended. The level of chloride that may be tolerated in such boilers during steady operation depends on the type of treatment employed. Where all-volatile alkaline treatments (AVT) are used, then the chloride levels should be lower than where nonvolatile alkalis (NVAT), such as sodium hydroxide and sodium phosphate, are used. The value may vary, depending on whether the boiler is coal-fired or oil-fired. 

AO AP AP/AO ASB ASME ASTM 1-AP ATMP AVAT AVP All-Organic 5-aminopentanol All-Polymer/All-Organic Shell Boiler Makers Association (UK) American Society of Mechanical Engineers American Society for Testing and Materials 1 -aminopyrrolidine aminotri-(methylenephosphonic acid) All-Volatile alkaline treatment All-Volatile programs... 

Figure 2.5 N2 adsorption isotherms and schematized silicon dissolution (inset) upon alkaline treatment ofZSM-5 zeolites with different framework Si/AI ratios, highlighting the crucial role of framework aluminum.

Not only the concentration but also the nature of the aluminum and its location (next section) plays a role in desilication by alkaline treatment. The presence of a... 

Most of the papers available on desilication are devoted to the alkaline treatment of ZSM-5 zeolites. Since a large number of zeolites consist of aluminosilicate frameworks and framework Al plays a crucial role in the mesoporosity development during desilication, this methodology should be suitable for extrapolation to other... 

Recently, the old alkaline phenol method has been revived, and is being widely used in clinical laboratories, without protein preclpltatlon(27). In this procedure, the serum is added to an alkaline phenol reagent, and the ammonia generated from urea is determined either after the action of urease or after strong alkaline treatment of the serum. The objection to this procedure is first, that all urease is rich in ammonia, and second, the color produced with alkaline phenol is not specific for ammonia. It will react with other compounds, especially for those that liberate ammonia. By this procedure one obtains a useful number from the point of view of determining whether the patient has nitrogen retention, but a value which is somewhere between a urea and an N.P.N. determination. 

Bioreactors containing an nndefined anaerobic consortinm rednced TNT to 2,4,6-triaminotoluene (TAT) in the presence of glncose (Dann et al. 1998). The sorption of TAT to montmorillonite clay was irreversible, and the snbstrate conld not be released by solvent extraction or by acid or alkaline treatment. Similar resnlts were obtained with humic acids in which covalent reactions with carbonyl or activated C=C bonding presumably occurred. Results from laboratory experiments nsing i C-labeled TNT in reactors to which... 

Less complex techniques have been reported to be useful to study the acidic and alkaline treatment processes of biosorbents and the role of carboxyl and carboxylate groups in metal adsorption. Rakhshaee and coworkers101 used potentiometric titration curves to assess the content of such groups in L. minor biomass treated with NaOH and HC1. The results showed an increase (up to 25%) in the adsorption of Hg(II), Cr(III), Cr(VI), and Cu(II) with NaOH-treated biomass as a consequence of an increase of -COO- groups (0.92-2.42 mmol/g). On the contrary, the -COOH groups increase observed (1.50-2.41 mmol/g) due to the acidic treatment led to a decrease in the metal ions uptake (up to 33%) despite activation by the chloride salts. 

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