Ethanol, 2- -, copper

Ethyl-2-pyridyl)ethanol Copper oxide Sodium hydride Sodium methylate Sodium acetate... 

Xu et al. [52] described an extraction of copper and cadmium from urine and digested tissue samples as the diethyldithiocarbamate (DDTC) complexes on reversed phase Cjg immobilized on silica gel and elution into FAAS by ethanol. Copper could be determined in all the samples with good sensitivity and accuracy. Cadmium in urine could also be determined without problems, and the detection limit was around 0.2 jig/liter with only 35 sec preconcentration, resulting in a sampling frequency of 85 per hour. However, in some tissue samples, such as liver, the values for cadmium were up to 50% low because of an interference by copper, as mentioned previously. 

Required Sulphuric acid, 3-3 ml. sodium dichromate, 3-5 g. ethanol, 1-5 ml. copper carbonate, 1 5 g. 

Prepare a mixture of 30 ml, of aniline, 8 g. of o-chloro-benzoic acid, 8 g. of anhydrous potassium carbonate and 0 4 g. of copper oxide in a 500 ml. round-bottomed flask fitted with an air-condenser, and then boil the mixture under reflux for 1 5 hours the mixture tends to foam during the earlier part of the heating owing to the evolution of carbon dioxide, and hence the large flask is used. When the heating has been completed, fit the flask with a steam-distillation head, and stcam-distil the crude product until all the excess of aniline has been removed. The residual solution now contains the potassium. V-phenylanthrani-late add ca. 2 g. of animal charcoal to this solution, boil for about 5 minutes, and filter hot. Add dilute hydrochloric acid (1 1 by volume) to the filtrate until no further precipitation occurs, and then cool in ice-water with stirring. Filter otT the. V-phcnylanthranilic acid at the pump, wash with water, drain and dry. Yield, 9-9 5 g. I he acid may be recrystallised from aqueous ethanol, or methylated spirit, with addition of charcoal if necessary, and is obtained as colourless crystals, m.p. 185-186°. 

The experimental conditions for conducting the above reaction in the presence of dimethylformamide as a solvent are as follows. In a 250 ml. three-necked flask, equipped with a reflux condenser and a tantalum wire Hershberg-type stirrer, place 20 g. of o-chloronitrobenzene and 100 ml. of diinethylform-amide (dried over anhydrous calcium sulphate). Heat the solution to reflux and add 20 g. of activated copper bronze in one portion. Heat under reflux for 4 hours, add another 20 g. portion of copper powder, and continue refluxing for a second 4-hour period. Allow to cool, pour the reaction mixture into 2 litres of water, and filter with suction. Extract the solids with three 200 ml. portions of boiling ethanol alternatively, use 300 ml. of ethanol in a Soxhlet apparatus. Isolate the 2 2- dinitrodiphenyl from the alcoholic extracts as described above the 3ueld of product, m.p. 124-125°, is 11 - 5 g. 

Finally, in the last step, the chelating auxiliary had to be removed Ideally, one would like to convert 4.54 into ketone 4.55 via a retro Mannich reaction. Unfortunately, repeated attempts to accomplish this failed. These attempts included refluxing in aqueous ethanol under acidic and basic conditions and refluxing in a 1 1 acetone - water mixture in the presence of excess paraformaldehyde under acidic conditions, in order to trap any liberated diamine. Tliese procedures were repeated under neutral conditions in the presence of copper(II)nitrate, but without success. 

It was discovered in 1940 that some acetylenic chlorides are converted into allenes by treatment with a zinc-copper couple in ethanol. This method appears to... 

In the flask were placed 40 ml of ethanol, 10 ml of water, 12 g of finely powdered CuCN and 0.40 mol of 3-bromo-l-butyne (compare VIII-2, Exp. 3). The mixture was warmed to 55°C and a solution of 26 g of KCN in 60 ml of water was added drop-wise or in small portions care was taken that complete dissolution of the copper cyanide did not occur (note 2). The temperature of the mixture was maintained close to 60°C throughout the period of addition. The conversion was terminated... 

To a suspension of a tinc-copper couple in 150 ml of 100 ethanol, prepared from 80 g of zinc powder (see Chapter II, Exp. 18), was added at room temperature 0.10 mol of the acetylenic chloride (see Chapter VIII-2, Exp. 7). After a few minutes an exothermic reaction started and the temperature rose to 45-50°C (note 1). When this reaction had subsided, the mixture was cooled to 35-40°C and 0,40 mol of the chloride was added over a period of 15 min, while maintaining the temperature around 40°C (occasional cooling). After the addition stirring was continued for 30 min at 55°C, then the mixture was cooled to room temperature and the upper layer was decanted off. The black slurry of zinc was rinsed five times with 50-ml portions of diethyl ether. The alcoholic solution and the extracts were combined and washed three times with 100-ml portions of 2 N HCl, saturated with ammonium chloride. 

A nice experiment illustrating the importance of a sample s matrix. The effect on the absorbance of copper for solutions with different %v/v ethanol, and the effect on the absorbance of chromium for solutions with different concentrations of added surfactants are evaluated. 

Oxidation. Acetaldehyde is readily oxidised with oxygen or air to acetic acid, acetic anhydride, and peracetic acid (see Acetic acid and derivatives). The principal product depends on the reaction conditions. Acetic acid [64-19-7] may be produced commercially by the Hquid-phase oxidation of acetaldehyde at 65°C using cobalt or manganese acetate dissolved in acetic acid as a catalyst (34). Liquid-phase oxidation in the presence of mixed acetates of copper and cobalt yields acetic anhydride [108-24-7] (35). Peroxyacetic acid or a perester is beheved to be the precursor in both syntheses. There are two commercial processes for the production of peracetic acid [79-21 -0]. Low temperature oxidation of acetaldehyde in the presence of metal salts, ultraviolet irradiation, or osone yields acetaldehyde monoperacetate, which can be decomposed to peracetic acid and acetaldehyde (36). Peracetic acid can also be formed directiy by Hquid-phase oxidation at 5—50°C with a cobalt salt catalyst (37) (see Peroxides and peroxy compounds). Nitric acid oxidation of acetaldehyde yields glyoxal [107-22-2] (38,39). Oxidations of /)-xylene to terephthaHc acid [100-21-0] and of ethanol to acetic acid are activated by acetaldehyde (40,41). 

Reduction. Acetaldehyde is readily reduced to ethanol (qv). Suitable catalysts for vapor-phase hydrogenation of acetaldehyde are supported nickel (42) and copper oxide (43). The kinetics of the hydrogenation of acetaldehyde over a commercial nickel catalyst have been studied (44). 

Other catalysts that can be used are boron trifluoride (5), copper—chromium oxides (6), phosphoric acid (7), and siUca-alurnina (8). Under similar conditions, ethanol yields /V-ethylaniline [103-69-5] and /V,/V-diethylaniline [91-66-7] (9,10). 

The compound can be prepared from 2,4,6-trinitrophenol (picric acid [88-89-1]) by reduction with sodium hydrosulfide (163), with ammonia —hydrogen sulfide followed by acetic acid neutralization of the ammonium salt (164), with ethanolic hydrazine and copper (165), or electrolyticaHy with vanadium sulfate in alcoholic sulfuric acid (159). Heating 4,6-dinitro-2-benzamidophenol in concentrated HQ. at 140°C also yields picramic acid (166). 

A Methylamino)phenol. This derivative, also named 4-hydroxy-/V-methy1ani1ine (19), forms needles from benzene which are slightly soluble in ethanol andinsoluble in diethyl ether. Industrial synthesis involves decarboxylation of A/-(4-hydroxyphenyl)glycine [122-87-2] at elevated temperature in such solvents as chlorobenzene—cyclohexanone (184,185). It also can be prepared by the methylation of 4-aminophenol, or from methylamiae [74-89-5] by heating with 4-chlorophenol [106-48-9] and copper sulfate at 135°C in aqueous solution, or with hydroquinone [123-31 -9] 2l. 200—250°C in alcohoHc solution (186). 

Cupric chloride or copper(II) chloride [7447-39 ], CUCI2, is usually prepared by dehydration of the dihydrate at 120°C. The anhydrous product is a dehquescent, monoclinic yellow crystal that forms the blue-green orthohombic, bipyramidal dihydrate in moist air. Both products are available commercially. The dihydrate can be prepared by reaction of copper carbonate, hydroxide, or oxide and hydrochloric acid followed by crystallization. The commercial preparation uses a tower packed with copper. An aqueous solution of copper(II) chloride is circulated through the tower and chlorine gas is sparged into the bottom of the tower to effect oxidation of the copper metal. Hydrochloric acid or hydrogen chloride is used to prevent hydrolysis of the copper(II) (11,12). Copper(II) chloride is very soluble in water and soluble in methanol, ethanol, and acetone. 

Hydrogenation of Acetaldehyde. Acetaldehyde made from acetylene can be hydrogenated to ethanol with the aid of a supported nickel catalyst at 150°C (156). A large excess of hydrogen containing 0.3% of oxygen is recommended to reduce the formation of ethyl ether. Anhydrous ethanol has also been made by hydrogenating acetaldehyde over a copper-on-pumice catalyst (157). 

One process (182) esterifi.es the acetic acid with ethanol (or methanol) and then converts the ester to alcohol by hydrogenolysis in the vapor phase over a copper—2inc catalyst. 

There are two ways to produce acetaldehyde from ethanol oxidation and dehydrogenation. Oxidation of ethanol to acetaldehyde is carried out ia the vapor phase over a silver or copper catalyst (305). Conversion is slightly over 80% per pass at reaction temperatures of 450—500°C with air as an oxidant. Chloroplatinic acid selectively cataly2es the Uquid-phase oxidation of ethanol to acetaldehyde giving yields exceeding 95%. The reaction takes place ia the absence of free oxygen at 80°C and at atmospheric pressure (306). The kinetics of the vapor and Uquid-phase oxidation of ethanol have been described ia the Uterature (307,308). 

The reaction kinetics for the dehydrogenation of ethanol are also weU documented (309—312). The vapor-phase dehydrogenation of ethanol ia the presence of a chromium-activated copper catalyst at 280—340°C produces acetaldehyde ia a yield of 89% and a conversion of 75% per pass (313). Other catalysts used iaclude neodymium oxide and samarium hydroxide (314). 

Ethylamines. Mono-, di-, and triethylamines, produced by catalytic reaction of ethanol with ammonia (330), are a significant outlet for ethanol. The vapor-phase continuous process takes place at 1.38 MPa (13.6 atm) and 150—220°C over a nickel catalyst supported on alumina, siUca, or sihca—alumina. In this reductive amination under a hydrogen atmosphere, the ratio of the mono-, di-, and triethylamine product can be controlled by recycling the unwanted products. Other catalysts used include phosphoric acid and derivatives, copper and iron chlorides, sulfates, and oxides in the presence of acids or alkaline salts (331). Piperidine can be ethylated with ethanol in the presence of Raney nickel catalyst at 200°C and 10.3 MPa (102 atm), to give W-ethylpiperidine [766-09-6] (332). 

The reaction is cataly2ed by all but the weakest acids. In the dehydration of ethanol over heterogeneous catalysts, such as alumina (342—346), ether is the main product below 260°C at higher temperatures both ether and ethylene are produced. Other catalysts used include siUca—alumina (347,348), copper sulfate, tin chloride, manganous chloride, aluminum chloride, chrome alum, and chromium sulfate (349,350). 

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