Acetaldehyde bromide

Metaldehyde [9002-91-9] a cycHc tetramer of acetaldehyde, is formed at temperatures below 0°C in the presence of dry hydrogen chloride or pyridine—hydrogen bromide. The metaldehyde crystallizes from solution and is separated from the paraldehyde by filtration (48). Metaldehyde melts in a sealed tube at 246.2°C and sublimes at 115°C with partial depolymerization. 

The usefulness of the Grignard reagent of 3-bromothiophene is somewhat limited as it can only be prepared by the entrainment method. The simultaneous formation of Grignard reagents from 3-bromothiophene and a fivefold molar excess of ethyl bromide gave, however, a 55% yield of 3-thiophenecarboxylic acid upon carbona-tion. With acetaldehyde, a 55% yield of methyl 3-thienyl carbinol... 

Ethyl bromide Acetaldehyde Diethyl malonate Ethanol Methyl urea... 

Preparation of 3-Hexyne-2-ol A solution of ethyl magnesium bromide was prepared by the reaction of 229 g of ethyl bromide and 4B.6 g of magnesium in 750 ml of anhydrous ether. To the ether solution was then added with stirring a solution of 10B g of ethyl acetylene in 250 ml of cold anhydrous ether. The addition required approximately 3 hours, and the mixture was stirred and refluxed for a further period of 3V2 hours. Thereafter there was added to the reaction mixture a solution of BB g of freshly distilled acetaldehyde in 170 ml of anhydrous ether, over a period of about 45 minutes and at a temperature in the range of about -10° to 0°C. 

In Figure 3 the merits of the two processes for p-xylene oxidation are compared. The main disadvantages of the Eastman Kodak/Toray cooxidation method are the need for a cosubstrate (acetaldehyde of methylethylketone) with concomitant formation of a coproduct (0.21 ton of acetic acid per ton product) and high catalyst concentration. The Amoco MC process, on the other hand, has no coproduct and much lower catalyst concentrations but has the disadvantage that the bromide-containing reaction mixture is highly corrosive, necessitating the use of a titanium-lined reactor. 

Oxalylchlorid 1930, 1950, 1953 Acetylfluorid, -chlorid, -bromid 1951 Acetaldehyd 1939, 1957 MW (38) p-Xylol 1935 Hexamethylbenzol 1935... 

Cool flame behaviour of acetaldehyde is apparently eliminated by tert-butyl bromide, and reduced by methyl iodide. 

Heptanol-2 has been prepared by the action of w-amyl magnesium bromide on acetaldehyde,1 and by the reduction of methyl w-amyl ketone in alcoholic solution by means of sodium.2... 

Indium Iodine Acetonitrile, nitrogen dioxide, mercury(II) bromide, sulfur Acetaldehyde, acetylene, aluminum, ammonia (aqueous or anhydrous), antimony, bromine pentafluoride, carbides, cesium oxide, chlorine, ethanol, fluorine, formamide, lithium, magnesium, phosphorus, pyridine, silver azide, sulfur trioxide... 

Several total syntheses of antirhine (11) and 18,19-dihydroantirhine (14) have been developed during the last decade. Wenkert et al. (136) employed a facile route to ( )-18,19-dihydroantirhine, using lactone 196 as a key building block. Base-catalyzed condensation of methyl 4-methylnicotinate (193) with methyl oxalate, followed by hydrolysis, oxidative decarboxylation with alkaline hydrogen peroxide, and final esterification, resulted in methyl 4-(methoxycar-bonylmethyl)nicotinate (194). Condensation of 194 with acetaldehyde and subsequent reduction afforded nicotinic ester derivative 195, which was reduced with lithium aluminum hydride, and the diol product obtained was oxidized with manganese dioxide to yield the desired lactone 196. Alkylation of 196 with tryptophyl bromide (197) resulted in a pyridinium salt whose catalytic reduction... 

If the action of methyl magnesium bromide on acetaldehyde be taken as example, the following equation holds ... 

In the DMT process, the esterification is done by feeding a slurry of TPA crystals in methanol to a reactor with a catalyst of sulfuric acid at 220°F and 50 psi. DMT forms and can be purified by distillation. Yields exceed 95%, based on the TPA that ends up as DMT. In some later designs resulting in less severe operating conditions, MEK or acetaldehyde have been used as promoters in place of sodium bromide. 

Methamidophos, see Acephate Methane, see Acetaldehyde, Benzoic acid, 7 Bromobenzoic acid. 3-Bromobenzoic acid. 4-Bromobenzoic acid. Bromoform, Carbatyl, Catechol, 2-Chlorobenzoic acid. 3-Chlorobenzoic acid. Chloroform, Dibromochloromethane, 2,5-Dichlorobenzoic acid. 1,2-Dichloroethane, Ethylamine, Ethyl bromide. Ethylene dibromide, Ethylenimine, Formic acid, Hydroqninone, 4 Hvdroxvbenzoic acid. Indole, 2-Iodobenzoic acid. 3 lodobenzoic acid. Methyl bromide, 4-Iodobenzoic acid. 2-Methylphenol, 4-Methylphenol, Phenol, Prorocatechuic acid. Svringic acid. Svringaldehvde. TCDD, Tetrachloroethylene, Toluene, Trichloroethylene, Vanillin. Vanillic acid. Vinyl chloride... 

Diethyl ethylidenemalonate has been prepared by heating acetaldehyde, diethyl malonate, and acetic anhydride 2 3 by heating the same reagents plus zinc chloride 4 by treating acetaldehyde and diethyl malonate with sodium ethoxide or piperidine 6 and by heating diethyl malonate, ethylidene bromide, and ethanolic sodium ethoxide.6... 

To increase the stereoselectivity of the aldol reaction, successful reaction of dibromo-/3 -lactams with methylmagnesium bromide followed by addition of acetaldehyde has been studied (equation 10/ . 

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