Oxidation with Lead Nitrate

Naphthaldehyde has been prepared from /3-chloro- or bromomethylnaphthalene by use of hexamethylenetetramine, or by oxidation with lead nitrate from /3-naphthoic acid by distillation with calcium formate, or by reduction with sodium amalgam in boric acid solution from /3-naphthylcarbinol by oxidation with chromic acid and from (3-naphthylglyoxylic acid by saponification, heating with aniline, and hydrolysis of the anil." It has been prepared from j8-naphthylmagnesium bromide and ethoxymethyleneaniline or orthoformic ester, ... 

Bromobenzaldehyde has been prepared by the oxidation of -bromotoluene with chromyl chloride/ by saponification of the acetal from />-bromophenylmagnesium bromide and orthoformic ester/ by the oxidation of ethyl -bromobenzyl ether with nitric acid/ by the oxidation of /j-bromobenzyl bromide with lead nitrate/ and by the hydrolysis of i-bromobenzal bromide in the presence of calcium carbonate. ... 

The same pattern of activity is maintained in a closely related analogue. Condensation of amino-sulfonamide 201 with aldehyde 202 affords the saturated heterocyclic system (203) oxidation with silver nitrate leads to the antihypertensive agent pazoxide (204). 49... 

Reaction of pyridine 1-oxide with benzoyl nitrate leads to the 3-nitro derivative the postulated mechanism is shown in Scheme 10. 

Condensation of 6-amino-5-nitrosouracils with ethanethiol and phenyl-methanethiol leads to formation of 8-substituted xanthines and 1,2,5-thiadiazolo[3,4-t/]pyrimidines [75JCS(P1) 1857]. Oxidation with lead tetraacetate forms furazano[3,4-with sodium nitrite or potassium nitrate and subsequent heating in DMF [73JHC415, 73JHC993 76JCS(P 1) 1327] (Scheme 65). 

P.P. Poppel and S.N. Khoroshevskaya, Interaction of Lead(II) Oxide with Molten Nitrates of Alkali Metals, Zh. Neorg. Khim. 30 (1985) 197-200. 

Chloroanisole and p-nitrophenol, the nitrations of which are susceptible to positive catalysis by nitrous acid, but from which the products are not prone to the oxidation which leads to autocatalysis, were the subjects of a more detailed investigation. With high concentrations of nitric acid and low concentrations of nitrous acid in acetic acid, jp-chloroanisole underwent nitration according to a zeroth-order rate law. The rate was repressed by the addition of a small concentration of nitrous acid according to the usual law rate = AQ(n-a[HN02]atoioh) -The nitration of p-nitrophenol under comparable conditions did not accord to a simple kinetic law, but nitrous acid was shown to anticatalyse the reaction. 

Acid Oxidation. Reactions of lead with acid and alkaUes are varied. Nitric acid, the best solvent for lead, forms lead nitrate acetic acid forms soluble lead acetate in the presence of oxygen sulfuric acid forms insoluble lead sulfate. Sulfuric acid is stored in containers with chemical or acid-grade lead. Lead dissolves slowly in HCl, but in the presence of aqueous alkaUes forms soluble plumbites and plumbates. 

Lead borate moaohydrate [14720-53-7] (lead metaborate), Pb(B02)2 H20, mol wt 310.82, d = 5.6g/cm (anhydrous) is a white crystalline powder. The metaborate loses water of crystallization at 160°C and melts at 500°C. It is iasoluble ia water and alkaHes, but readily soluble ia nitric and hot acetic acid. Lead metaborate may be produced by a fusion of boric acid with lead carbonate or litharge. It also may be formed as a precipitate when a concentrated solution of lead nitrate is mixed with an excess of borax. The oxides of lead and boron are miscible and form clear lead-borate glasses in the range of 21 to 73 mol % PbO. 

Arsenates are oxidizing agents and are reduced by concentrated hydrochloric acid or sulfur dioxide. Treatment of a solution of orthoarsenate with silver nitrate in neutral solution results in the formation of a chocolate-brown precipitate of silver orthoarsenate, Ag AsO, which may be used as a test to distinguish arsenates from phosphates. With hydrofluoric acid, orthoarsenate solutions yield hexafluoroarsenates, eg, potassium hexafluoroarsenate [17029-22-0] (KAsFg)2 H2O. Arsenates of calcium or lead are used as insecticides sodium arsenate is used in printing inks and as a mordant. 

Heating with the following solids, their fusions, or vapours (a) oxides, peroxides, hydroxides, nitrates, nitrites, sulphides, cyanides, hexacyano-ferrate(III), and hexacyanoferrate(II) of the alkali and alkaline-earth metals (except oxides and hydroxides of calcium and strontium) (b) molten lead, silver, copper, zinc, bismuth, tin, or gold, or mixtures which form these metals upon reduction (c) phosphorus, arsenic, antimony, or silicon, or mixtures which form these elements upon reduction, particularly phosphates, arsenates,... 

The early studies on the exchange system, carried out by Muxart et al., Menker and Garner, and Burgus and Kennedy, showed the exchange to be slow in sulphate , perchlorate, nitrate, and hydroxide media -. The isotopic method ( Cr) was used with separation of the Cr(III) and Cr(VI) being achieved by the precipitation of chromic oxide and lead chromate. Some evidence was obtained for the retardation of the exchange by hydrogen ions. 

A pyrotechnic mixture of sulphide/potassium chlorate/aluminium has led to regular detonations. This sulphide incandesces as soon as it is in contact with chloric acid. Mixtures of antimony trisuiphide with alkaline nitrates, which are probably used for pyrotechnic purposes, also lead to detonations. Bengal lights has been made with this mixture, which was used in small quantities in mixtures and no accidents were experienced. Finally, dichlorine oxide detonates in contact with this sulphide. 

The losses of lead as litharge (PbO) can be minimized if the impurity elements could be oxidized at an oxygen potential lower than that which causes the oxidation of lead. This can be achieved if the activities of the oxides of the impurity elements in the slag are decreased, for example, by the addition of an oxide which reacts very much more strongly with the oxides of the impurities than it does with lead oxide. Sodium hydroxide is a useful reagent for this purpose and sodium nitrate can be used as the source of oxygen. The reaction involved in this process, known as the Harris process, can be formally written as... 

This type of pigment is the precipitate formed when molybdic oxide is dissolved in aqueous sodium hydroxide with the addition of sodium chromate. The resulting mixture is reacted with a solution of lead nitrate. The precipitate formed is further processed through filtration, washing, drying, milling, and packaging. 

Oxidation of the complexes [Ag(Py)4][MoF6] and [Ag(Py)2][UF6] in acetonitrile by MoF6 and UF6, respectively, leads to the silver(III) compounds [Ag(Py)4(NCMe)][MoF6]3 and [Ag(Py)2(NC-Me)3][UF6]3, which are strong oxidizing agents.167 Other pyridine silver(III) complexes have been obtained by oxidation of silver nitrate and ammonia with ammonium peroxydisulfate in aqueous... 

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