Ammonium dichromate, alcohol

Dichromated Resists. The first compositions widely used as photoresists combine a photosensitive dichromate salt (usually ammonium dichromate) with a water-soluble polymer of biologic origin such as gelatin, egg albumin (proteins), or gum arabic (a starch). Later, synthetic polymers such as poly(vinyl alcohol) also were used (11,12). Irradiation with uv light (X in the range of 360—380 nm using, for example, a carbon arc lamp) leads to photoinitiated oxidation of the polymer and reduction of dichromate to Ct(III). The photoinduced chemistry renders exposed areas insoluble in aqueous developing solutions. The photochemical mechanism of dichromate sensitization of PVA (summarized in Fig. 3) has been studied in detail (13). 

The procedure described is that of Wille and Saffer. Propiolaldehyde has also been prepared by the oxidation of propargyl alcohol using ammonium dichromate or manganese dioxide in 10% sulfuric acid. Propiolaldehyde has also been prepared by warming the dimethyl or diethyl acetal with dilute sulfuric acid. ... 

I-A1ON0-2-NAPHIH0L-4-SULE0NIC acid, 11, 72 16, 91 17, 91 Aminonaphtholsulfonic acids, coupling to form azo dyes, 16,16 p-Aminophenol, 16, 39 Aminopiperole, 16, 6 /3-Ahinopropionic acid, 16, 1 4-Aminoveratrole, 16, 4 Ammonium dichromate, 16, 74 Ammonium formate, 17, 77 Ammonium thiocyanate, 16, 74 Ammonium vanadate, 13, 1 to w-Amyl alcohol, IS, 17 hri.-Amyl alcohol, 13, 68 -Amylbenzene, 10, 4 -Amyl borate, 13, 17 -Amyl bromide, 16, 41 iso-Amyl iodide, 13, 62 n-Amyl iodide, 13, 62 n-Amybnagnesium bromide, 16, 41... 

An effective oxidation of a,p-unsaturated primary alcohols and benzylic alcohols, but not saturated alcohols, to the corresponding aldehydes has been achieved using polymer-supported quaternary ammonium dichromate [14],... 

Chromium tetraphenyl dichromate, [(C6H5)4Cr]2Cr207, is obtained by allowing ammonium dichromate in methyl alcohol to... 

The oxidative potency of dichromates and chlorochromates decreases under less acidic conditions. This is so, for example, when a less acidic ammonium salt is included as counter-ion of a dichromate or chlorochromate anion. Thus, a number of ammonium dichromates and chlorochromates possessing a milder oxidative potency has been described with the specific purpose of allowing very selective oxidations of unsaturated alcohols in the presence of saturated ones. These selective dichromates and chlorochromates include bis(benzyltriethylammonium)dichromate,135 tetramethylethy-lenediammonium dichromate (TMEDADC),136 imidazolium dichromate (IDC),137 N, A -dimeth y I a m i n o py r id i n i u m chlorochromate (DMAPCC),138 l-(benzoylamino)-3-methylimidazolium chlorochromate (BAMICC)139 and butyltriphenylphosphonium chlorochromate (BTPPCC).140... 

A copper-chromium oxide on pumice catalyst has particular value for the dehydrogenation of primary and secondary alcohols to the corresponding carbonyl compounds (see Section 5.6.1, p. 581). Dissolve 10.4g of barium nitrate (AnalaR) in 280 ml of water at about 80 °C and add to this hot solution 87 g of copper(n) nitrate trihydrate (AnalaR) stir the mixture and heat until a homogeneous solution results. Prepare a solution of 50.4 g of recrystallised ammonium dichromate in a mixture of 200 ml of water and 75 ml of concentrated ammonia solution (d 0.880). To the ammonium chromate solution at 25-30 °C add the hot (80 °C) nitrate solution in a thin stream with stirring. Allow the mixture to cool and filter off the yellowish-brown precipitate with suction press with a glass stopper and suck as dry as possbile. Transfer the... 

Ammonium Chromithiocyanate, (NH4)3[Cr(SCN)6].4H20, is formed by dissolving freshly precipitated hydroxide in ammonium-thiocyanate solution, or by reducing ammonium dichromate wth alcohol and sulphuric acid, neutralising the solution with ammonia, adding ammonium thiocyanate, and boiling for a short time. ... 

B. Reinitzer said that the salt is soluble in absolute alcohol. W. P. Jorissen discussed the limits of the reaction of ammonium dichromate with potassium chloride and sulphate. 

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