Alkaline hydrolysis ammonium hydroxide

Kasuganobiosamine (4) and Kasugamycinic Acid (9a) by cold Alkaline Hydrolysis. Kasugamycin hydrochloride (622 mg., 1.43 mmoles) was dissolved in 5 ml. of water free from carbon dioxide and 50 ml. of water saturated with barium hydroxide was added. The solution was allowed to stand at room temperature for 36 hours. Ammonia (0.30 mmole) was produced and barium oxalate (199 mg., 0.80 mmole) was obtained. After removal of barium oxalate by filtering, the filtrate was neutralized with dry ice. After removal of barium carbonate by filtering, the filtrate was adjusted to pH 7.0 and placed on a column of Amberlite CG-50 (ammonium form, 1.5 x 22 cm.), allowed to pass with a rate of... 

Formazans are stable in alkaline solution. Alkaline hydrolysis of functionalities on formazans such as nitriles, esters, and amides leads to the acids (Section 7.3.1.1). The case of 3-nitroformazans (198) is unique. Reaction with hydroxide ion gives 3-hydroxy formazan (199) which can be readily oxidized to the tetrazolium betaine. In the presence of hydrosulfide, a reduction of the nitro group takes place giving 3-aminoformazan (200) with traces of the 3-mercaptoformazan (201), which by contrast is the main product when ammonium polysulfide is used (Scheme 30).45,346... 

The procedure given is essentially that described by Taylor and Crovetti.3 Nicotinamide-1-oxide (m.p. 275-276° dec.) has also been prepared by the alkaline hydrolysis of nicotinonitrile-1-oxide 4 and by the action of ammonium hydroxide on methyl nicotinate-l-oxide.6 The melting point of the product prepared by the latter synthesis is reported to be 282-284° dec. 

The 3-4 Cals, here represent the heat of admixture of a mol of ammonia with water, and this is much greater than the heat of admixture of ammonia with other liquids which do not react chemically with the ammonia. There is also a possibility that ammonia hydrates. NH3.nH20, are formed, vide infra and a possibility that the ammonium hydroxide is ionized NH OH NH +OH. In agreement with the assumption that ammonium hydroxide is formed which acts as a weak base, the liquid tastes alkaline it reddens turmeric colours the juice of violets green and colours litmus, etc., the same as do soln. of the alkali hydroxides. These changes of colour disappear on exposure to air owing to the volatilization of the ammonia— the volatile alkali of the early chemists. The feeble character of ammonium hydroxide as a base is evidenced by its heat of neutralization with acids which is about 1-5 Cals, less than is the case with potassium or sodium hydroxides like other weak bases, the soln. cannot be satisfactorily titrated with phenolphthalein S. Arrhenius found that its effect on the hydrolysis of ethyl acetate is about 40 times leBS than that of sodium hydroxide and the electrical conductivity of aq. soln. of... 

It remains to be explained why treatment of the protected nucleotide (153) with ammonium hydroxide produces cytidine 2 -phosphate only, whereas similar treatment of (156) gives a mixture of the 2 - and 3 -isomers. A possible explanation may reside in differences in the lability of the benzoyl group on 0-2 or 0-3 of ribonucleosides, the 2 -benzoate being the more labile to ammonium hydroxide. Such a hypothesis is in accordance with the observation that partial debenzoylation of iV -benzoyl-tri-0-benzoylcytidine yields a mixture containing (152), but not (155). It had been noted that, in ribonucleosides, the 2 -hydroxyl group is more acidic than the 3 - and 5 -hydroxyl groups. It would be expected that 2 -0-acyl derivatives of ribonucleosides should be relatively more susceptible to alkaline hydrolysis than the 3 - or 5 -0-acyl derivatives. 

The alkaline hydrolysis of PET involves treating the polyester with an aqueous solution of sodium hydroxide (4-20 wt%) under pressure at temperatures between 200 and 250 °C for periods of several hours.53,54 Under these conditions the sodium salt of TPA is formed and by acidification TPA is recovered from the solution as a precipitate. It has been observed that the rate of the PET alkaline hydrolysis increases in the presence of quaternary ammonium compounds. Thus, Niu et al.55 have reported on the alkaline degradation of PET fibres with addition of dodecylbenzyldimethylammonium chloride (DBDMAC) into the reaction mixture. A sharp increase in the PET hydrolytic degradation at 80 °C was observed with DBDMAC concentrations in the range 0-1.0 g/1, especially for the least crystalline fibres. The authors concluded that the rate enhancement by quaternary ammonium compounds occurs preferentially on the amorphous regions of the PET fibres. 

The 1-methylamino derivative 71 behaves like a typical secondary amine, forming a benzoyl derivative with benzoyl chloride and a N-nitroso compound with nitrous acid. Alkaline hydrolysis results in ring opening to give caffeidine (75). The parent heterocycle and its 3-methyl derivative form 7-oxides on treatment with m-chloroperbenzoic acid. The 3-thioxo compound 65 is readily desulfurized by Raney nickel in ammonium hydroxide solution. ... 

With the procedure of Okishio et al. (24,124) freeze-dried rat liver homogenates are exhaustively extracted with 95% ethanol containing 0.1% ammonium hydroxide, and the extract is taken to dryness. The residue is dissolved in aqueous NaOH, pH 11, and applied to an Amberlyst A-26 anion exchanger. After alkaline or enzymatic hydrolysis the free bile acids are extracted with diethyl ether after acidification. The bile acids are methylated and then purified on aluminum oxide. The bile acid methyl ester fraction eluted from this column is taken to dryness and the residue is trifluoroacet-ylated and analyzed on a triple-component column (QF-1-SE-30-NGS) for quantitative determination. 

Alkaline hydrolysis was carried out in order to remove PS and PE that can be extracted together with the psychosine. After the alkaline hydrolysis, the extract was washed three times with upper phase containing ammonium hydroxide. If the extract (checked by TLC) had still some contaminants as cerebrosides or sulphatides, a preparative TLC was carried out using chloroform methanol 2 N-NH3 60 35 8 as solvent in order to remove them. The spots were identified by spraying the plate with fluorescamine reagent in acetone (4-phenyl-spiro fu-ran-2 (3H) I -phtalan 3,3-dione) Hoffmann La Roche, Nut ley, U.S.A. 

Our assay for the detection of active acetate was based on the enzymic reaction with sulfanilamide. In the presence of the enzyme obtained from pigeon liver, the acetylation of sulfanilamide increased with increasing addition of active acetate . In our purification work we used, however, another, much less time-consuming assay which was based on the delayed color development as given by thiolesters with sodium nitro-prusside. When ammonium hydroxide is added to the mixture of thiolesters and nitroprusside no color is seen in the first moment. It only gradually develops in the following minutes due to the hydrolysis of the thiolester in the alkaline medium. The... 

ALKALINE SOLUTIONS. Alkaline solutions generally have some action on aluminum alloys. The pH of these solutions alone is not a reliable indicator of the performance of aluminum alloys. Usually, weak bases such as ammonium hydroxide, hex-amine, alkanolamines and their aqueous solutions can be handled in aluminum because a protective film forms on aluminum after an initial period of reaction. Solutions made alkaline by hydrolysis of basic salts such as sodium carbonate form protective films on Al-Mg alloys containing 3.5% or more magnesium. Strong bases such as sodium hydroxide and potassium hydroxide dissolved in water are very corrosive and should not be handled in aluminum. See also Ref (4) pp. 35, 37. 

Acids such as sulfuric or nitric acids or bases such as sodium hydroxide may catalyze the hydrolysis of PET. It has been demonstrated that the rate of alkaline PET hydrolysis increases in the presence of quaternary ammonium compounds.26 27 Niu et al.26 reported an increase in the rate of alkaline PET degradation in the presence of dodecylbenzyldimethylammonium chloride at 80°C. Polk et al.27 reported increases in the rate of sodium hydroxide depolymerization of PET in the presence of trioctylmethylammonium chloride, trioctyl-methylammonium bromide, and hexadecyltrimethylammonium bromide at 80° C. 

In acid catalysis (HCl), the variation in pH of the medium affects the yield of oligoorganylsilsesquioxanes to a lesser extent than in the case of alkaline catalysis. Base catalysts are used in the synthesis of oligosilsesquioxanes mainly in the thermolysis of the primary products of XSiYj hydrolysis (Table 1). The most efficient catalysts, in this case, are those which are readily decomposed upon heating to give inactive products For example, the use of tetraethylammonium 32,45) trimethyl-benzyl ammonium 23.37,41) triethylamine hydroxides has proved successful. 

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