DICHROMATE/SULFURIC ACID

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). 

The glassware was cleaned in a sodium dichromate-sulfuric acid bath, washed with aqueous 10% ammonium hydroxide, and rinsed with water. The extent of enolization apparently depends on the care taken in washing the glassware and conducting the distillation. 

Sodium dichromate, Sulfuric acid See Sodium dichromate Sulfuric acid, Trinitrotoluene... 

A closed bottle of unused potassium dichromate-sulfuric acid mixture exploded after several months in storage [1]. Previous similar incidents were summarised, and the possibility of the bottle having burst from internal pressure of carbon dioxide arising from trace contamination by carbon compounds was advanced [1,2], Two further reports of incidents within 1 or 2 days of preparation of... 

Dining glass cleaning operations, acetone splashed into a beaker used previously to contain potassium dichromate-sulfuric acid mixture and the solvent ignited. Alcohols behave similarly. 

Toluidines 2,4,6-Trinitrotoluene 1,3,5-Trioxane Urea Vinylidene chloride Nitric acid Sodium dichromate, sulfuric acid Oxidizing materials, acids Sodium nitrite, phosphorus pentachloride Chlorosulfonic acid, nitric acid, oleum... 

Diazirines have been prepared by dehydrogenation of diaziri-dines with mercuric oxide, silver oxide, or dichromate-sulfuric acid. The present procedure corresponds to that of Schmitz and Ohme. The procedure for the preparation of the 3,3-penta-methylenediaziridine has been reported by H. J. Abendroth. ... 

D. Dichromate-Sulfuric Acid Reagent is prepd by dissolving 0.5g of K2Cr207 in 100ml of 60% sulfuric acid. It was proposed by Oven-ston for use in chromatographic analysis of propints, for the location of substituted ureas and urethanes which have been employed as stabilizers and plasticizers(Ref 18a)... 

This oxidation fails with strong oxidants like dichromate-sulfuric acid, because of decomposition of the sydnone ring, while mild oxidants like M11O2 cause no reaction. The use of a 1 1 mixture of DMSO and Ac20, instead of the conditions indicated above, leads to a 38% yield of the corresponding acetate, and to a decrease in the yield of ketone to 46%. 

Chromic acid etch (sodium dichromate-sulfuric acid) Maximum-strength... 

The sodium dichromate-sulfuric acid process has been found by some to be superior to other ferric chloride methods for the prebond treatment of copper. This dichromate-sulfuric acid method is also defined by ASTM D 2651. Nitric acid and ferric chloride etching processes have also been found to be useful for copper, brass, and bronze substrates in certain applications. 

Generally only solvent cleaning and abrasion are necessary for surface preparation of polystyrene parts. Methanol and isopropanol are acceptable solvents for solvent cleaning of polystyrene. For maximum bond strength the substrates can be etched with sodium dichromate-sulfuric acid solution at elevated temperature. Table 16.14 shows the results of a study on the durability of joints formed between polystyrene and aluminum with different types of adhesives exposed to different environments. 

Suppose you have just synthesized heptanoic acid from heptan- l-ol. The product is contaminated by sodium dichromate, sulfuric acid, heptan- l-ol, and possibly heptanal. Explain how you would use acid-base extractions to purify the heptanoic acid. Use a chart, like that in Figure 20-3, to show where the impurities are at each stage. 

Highly dangerous explodes with shock or heating to 297°C. Various materials can reduce the explosive temperature red lead -(to 192°C), sodium carbonate (to 218°C), potassium hydroxide (to 192°C). Mixtures with sodium dichromate + sulfuric acid may... 

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