Catalysis alcohol

Aldehydes and Ketones. Esters are obtained readily by condensation of aldehydes in the presence of alcoholate catalysis such as aluminum ethylate, AI(OC H5) , by the Tishchenko reaction. 

Scheme 6.15 Alcohol catalysis of HDA reactions of diene 115 with ketones.

Several arylboron compounds bearing electron-withdrawing aromatic groups have been examined as catalysts for the OPP oxidation of (5)-perillyl alcohol. Catalysis has been performed with 1 to 2 mol % catalyst in the presence of 6 equiv. pivalaldehyde as hydride acceptor in toluene or benzene solution. Representative results are summarized in Table 1. 

Scheme 1.5. Alcohol catalysis of the epoxy-ring-opening reaction by amine groups (the -OH may arise from impurities in the resin, the resin itself, e.g. DGEBA, Scheme 1.4, or following ring-opening of another epoxy group. Scheme 1.3). Reproduced with permission from St John (1993).

Cui X, Shi F, Beller M et al (2009) Copper-catalyzed N-alkylation of sulfonamides with benzylic alcohols catalysis and mechanistic studies. Adv Synth Catal 351(17) 2949-2958... 

Keywords Alcohols Catalysis Dehydrogenation Formic acid Ruthenium... 

Turek, T., Trimm, D.L., Cant, N.W., 1994. The catalytic hydrogenolysis of esters to alcohols. Catalysis Reviews Science and Engineering 36, 645-683. 

Schiff base fonnation, photochemistry, protein partitioning, catalysis by chymotrypsin, lipase, peroxidase, phosphatase, catalase and alcohol dehydrogenase. 

The reaction takes place extremely rapidly and if D2O is present in excess all the alcohol is con verted to ROD This hydrogen-deuterium exchange can be catalyzed by either acids or bases If D30 is the catalyst in acid solution and DO the catalyst in base wnte reasonable reaction mech anisms for the conversion of ROH to ROD under conditions of (a) acid catalysis and (b) base catalysis... 

These reactions are usually performed in water or alcohols as solvents and the alkox ide ion intermediate is rapidly transformed to an alcohol by proton transfer The other involves acid catalysis Here the nucleophile is often... 

Many of the most interesting and useful reactions of aldehydes and ketones involve trans formation of the initial product of nucleophilic addition to some other substance under the reaction conditions An example is the reaction of aldehydes with alcohols under con ditions of acid catalysis The expected product of nucleophilic addition of the alcohol to the carbonyl group is called a hemiacetal The product actually isolated however cor responds to reaction of one mole of the aldehyde with two moles of alcohol to give gem mal diethers known as acetals... 

The point was made earlier (Section 5 9) that alcohols require acid catalysis in order to undergo dehydration to alkenes Thus it may seem strange that aldol addition products can be dehydrated in base This is another example of the way in which the enhanced acidity of protons at the a carbon atom affects the reactions of carbonyl com pounds Elimination may take place in a concerted E2 fashion or it may be stepwise and proceed through an enolate ion... 

Acyl transfer from an acid an hydride to an alcohol is a standard method for the prep aration of esters The reaction IS subject to catalysis by either acids (H2SO4) or bases (pyri dine)... 

Acetals are readily formed with alcohols and cycHc acetals with 1,2 and 1,3-diols (19). Furfural reacts with poly(vinyl alcohol) under acid catalysis to effect acetalization of the hydroxyl groups (20,21). Reaction with acetic anhydride under appropriate conditions gives the acylal, furfuryUdene diacetate... 

Furfuryl alcohol is comparable to kerosene or No. 1 fuel oil in flammabiUty, the Tag Closed Cup flash point is 170°F. In the presence of concentrated mineral acids or strong organic acids, furfuryl alcohol reacts with explosive violence. Therefore, precautions should be taken to avoid contact of such materials with the alcohol. Caution is also recommended to avoid over-catalysis in the manufacture of furfuryl alcohol resins. 

High Carbon Yield. Furfuryl alcohol and furfural are reactive solvents (monomers) and are effective in producing high carbon yield (heat induced carbonization in a reducing atmosphere). They function as binders for refractory materials or carbon bodies. Furfuryl alcohol usually requires acidic catalysis and furfural basic catalysis. Mixtures of furfuryl alcohol and furfural are generally catalyzed with acid although some systems may be catalyzed with base. 

Furfuryl alcohol alone, or in combination with other cross-linkable binders such as phenoHc reins, chemical by-products and pitch, catalyzed with acid, gives carbon yields of 35—56%. Furfural together with cyclohexanone, pitch, or phenoHc resins gives, under acid catalysis, yields of 35—55% carbon under basic catalysis yields of 5—50% are achieved. FurfuryHdeneacetone resins (13 and 14), catalyzed by acid or base, give carbon yields of 48—56 and... 

Chromium compounds decompose primary and secondary hydroperoxides to the corresponding carbonyl compounds, both homogeneously and heterogeneously (187—191). The mechanism of chromium catalyst interaction with hydroperoxides may involve generation of hexavalent chromium in the form of an alkyl chromate, which decomposes heterolyticaHy to give ketone (192). The oxidation of alcohol intermediates may also proceed through chromate ester intermediates (193). Therefore, chromium catalysis tends to increase the ketone alcohol ratio in the product (194,195). 

Acetylene is condensed with carbonyl compounds to give a wide variety of products, some of which are the substrates for the preparation of families of derivatives. The most commercially significant reaction is the condensation of acetylene with formaldehyde. The reaction does not proceed well with base catalysis which works well with other carbonyl compounds and it was discovered by Reppe (33) that acetylene under pressure (304 kPa (3 atm), or above) reacts smoothly with formaldehyde at 100°C in the presence of a copper acetyUde complex catalyst. The reaction can be controlled to give either propargyl alcohol or butynediol (see Acetylene-DERIVED chemicals). 2-Butyne-l,4-diol, its hydroxyethyl ethers, and propargyl alcohol are used as corrosion inhibitors. 2,3-Dibromo-2-butene-l,4-diol is used as a flame retardant in polyurethane and other polymer systems (see Bromine compounds Elame retardants). 

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