Aldehydes, atmosphere

Gattermann-Koch reaction Formylation of an aromatic hydrocarbon to yield the corresponding aldehyde by treatment with CO, HCl and AICI3 at atmospheric pressure CuCl is also required. The reaction resembles a Friedel-Crafts acylation since methanoyl chloride, HCOCl, is probably involved. 

Fehling s solution. Aqueous solutions of aliphatic aldehydes are almost invariably acidic owing to atmospheric oxidation, and therefore... 

Action of sodium hydroxide. Does not undergo the Cannizzaro reaction. It dissolves in dil. NaOH solution, giving a yellow solution from which the aldehyde is precipitated unchanged on acidification. If heated with cone. NaOH solution, salicylaldehyde slowly undergoes atmospheric oxidation to salicylic acid. 

In the early 1920s Badische Arulin- und Soda-Fabrik aimounced the specific catalytic conversion of carbon monoxide and hydrogen at 20—30 MPa (200—300 atm) and 300—400°C to methanol (12,13), a process subsequendy widely industrialized. At the same time Fischer and Tropsch aimounced the Synth in e process (14,15), in which an iron catalyst effects the reaction of carbon monoxide and hydrogen to produce a mixture of alcohols, aldehydes (qv), ketones (qv), and fatty acids at atmospheric pressure. 

Shipment Methods and Packaging. Pyridine (1) and pyridine compounds can be shipped in bulk containers such as tank cars, rail cars, and super-sacks, or in smaller containers like fiber or steel dmms. The appropriate U.S. Department of Transportation (DOT) requirements for labeling are given in Table 4. Certain temperature-sensitive pyridines, such as 2-vinylpyridine (23) and 4-vinylpyridine are shipped cold (<—10°C) to inhibit polymerisation. Piperidine (18) and certain piperidine salts are regulated within the United States by the Dmg Enforcement Agency (DEA) (77). Pyridines subject to facile oxidation, like those containing aldehyde and carbinol functionaUty, can be shipped under an inert atmosphere. 

The ethylene oxide recovered in the desorber contains some carbon dioxide, nitrogen, aldehydes, and traces of ethylene and ethane. In the stripper the light gases are separated overhead and vented, and the partially purified ethylene oxide is sent from the bottom of the stripper to the mid-section of a final refining column. The ethylene oxide from the refining section should have a purity of >99.5 mol %. The final product is usually stored as a Hquid under an inert atmosphere. 

In this step the recovered ether is collected in a dry atmosphere, and about 100 ml. of this ether is used in two portions to extract the sodium sulfate residue in order to transfer into the flask any small quantities of the aldehyde that may have been trapped by the drying agent. 

Styrene oxide [96-09-3] M 120.2, b 84-86 /16.5mm, d 1.053, n 1.535. Fractional distn at reduced pressure does not remove phenylacetaldehyde. If this material is present, the styrene oxide is treated with hydrogen under 3 atmospheres pressure in the presence of platinum oxide. The aldehyde, but not the oxide, is reduced to 6-phenylethanol) and separation is now readily achieved by fractional distn. [Schenck and Kaizermen J Am Chem Soc 75 1636 1953.]... 

In a German patent issued in 1929, Bergs described a synthesis of some 5-substituted hydantoins by treatment of aldehydes or ketones (1) with potassium cyanide, ammonium carbonate, and carbon dioxide under several atmospheres of pressure at 80°C. In 1934, Bucherer et al. isolated a hydantoin derivative as a by-product in their preparation of cyanohydrin from cyclohexanone. They subsequently discovered that hydantoins could also be formed from the reaction of cyanohydrins (e.g. 3) and ammonium carbonate at room temperature or 60-70°C either in water or in benzene. The use of carbon dioxide under pressure was not necessary for the reaction to take place. Bucherer and Lieb later found that the reaction proceeded in 50% aqueous ethanol in excellent yields for ketones and good yields for aldehydes. ... 

A solution of 10 g of 9 10-dihydro-9 10-ethano-(1 2)-anthracene-(9)aldehyde (made from anthracene and acrolein) and 10 g of monomethylamine in 100 cc of ethanol is heated at 80°C for 4 hours in an autoclave. The reaction mixture is then evaporated to dryness under reduced pressure to leave a crystalline residue which is dissolved in 150 cc of ethanol and, after the addition of 2 g of Raney nickel, hydrogenated at 40°C under atmospheric pressure. When the absorption of hydrogen has subsided, the catalyst is filtered off and the filtrate evaporated under reduced pressure. An oil remains which is covered with 100 cc of 2N hydrochloric acid. The 9-methylamino-methyI-9 10-dihydro-9 10-ethano-(9 10)-anthracene hydrochloride crystallizes immediately after crystallization from methanol it melts at 320°-322°C. 

S g of ethyl glycinate hydrochloride were dissolved in 400 cc of ethanol and 33.5 g of salicylic aldehyde were added. It is refluxed for half an hour and cooled. 38 cc of triethylamlne and 25 g of Raney nickel are then added whereafter hydrogenation is carried out at room temperature and under atmospheric pressure. After hydrogen adsorption was complete, the mixture was filtered and the alcohol evaporated off. The residue was taken up with acidified water, extracted with ether to eliminate part of the by-products, consisting mainly of o-cresol, then made alkaline with ammonia and extracted with ethyl acetate. The solvent was removed in vacuo and the residue crystallized from ether/petroleum ether. 36.7 g of o-hydroxybenzyl-aminoacetlc acid ethyl ester melting at 47°C are obtained. 

Howarth oxidized various aromatic aldehydes to the corresponding carboxylic acids with Ni(acac)2 dissolved in [BMIM][PF ] as the catalyst and oxygen at atmospheric pressure as the oxidant [59]. However, this reaction cannot be considered a... 

Much like the oxidation of propylene, which produces acrolein and acrylic acid, the direct oxidation of isobutylene produces methacrolein and methacrylic acid. The catalyzed oxidation reaction occurs in two steps due to the different oxidation characteristics of isobutylene (an olefin) and methacrolein (an unsaturated aldehyde). In the first step, isobutylene is oxidized to methacrolein over a molybdenum oxide-based catalyst in a temperature range of 350-400°C. Pressures are a little above atmospheric ... 

At elevated temperatures, methylene carbons cleave from aromatic rings to form radicals (Fig. 7.44). Further fragmentation decomposes xylenol to cresols and methane (Fig. 7.44a). Alternatively, auto-oxidation occurs (Fig. 1.44b ). Aldehydes and ketones are intermediates before decarboxylation or decarbonylation takes place to generate cresols and carbon dioxide. These oxidative reactions are possible even in inert atmospheres due to the presence of hydroxyl radicals and water.5... 

The rapid synthesis of 4-thiazolidinones by the MCR of an amine, aldehyde and mercaptoacetic acid has been developed under microwave-assisted conditions [73-75]. Irradiation of the three components in ethanol at 120 °C in the presence of molecular sieves [73] or in toluene at reflux under atmospheric conditions [74] in a single-mode microwave synthesizer gave the... 

Various l-alkyl-4-(benzotriazol-l-yl)-l,2,3,4-tetrahydroquinolines have been prepared by condensation of V-alkylaniline with two equivalents of an aldehyde and one equivalent of benzotriazole <95JOC(60)7631>. Quinolones 66 were simply prepared in good yield by heating a mixture of the appropriate vinylogous amide 65 and NaHCOj in the presence of a catalytic amount of palladium(II) acetate and triphenylphosphine in DMF under a carbon monoxide atmosphere <96CC2253>. 

EtsSiH 84b (2-3 equiv.) is added at room temperature, under an argon atmosphere, to a stirred mixture of 2-5 mol% 10% Pd on carbon and a 0.5-1 M solution of thiol ester 1849 in acetone. Stirring is continued at room temperature until reduction is complete (30-60 min). The catalyst is isolated by filtration through Cehte and washed with acetone. Evaporation, and separation on a sihca gel column, gives the desired aldehyde 1850 in 91% yield [76] (Scheme 12.67). 

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