Acetic acid catalysts

Bromohydrins can be prepared direcdy from polyhydric alcohols using hydrobromic acid and acetic acid catalyst, followed by distillation of water and acetic acid (21). Reaction conditions must be carehiUy controlled to avoid production of simple acetate esters (22). The raw product is usually a mixture of the mono-, di-and tribromohydrins. 

Fig. 16. Relation between the optical yield and the amount of pivalic acid and acetic acid in ihe cnanlioface-difl erentiating hydrogenation of 2-octanonc with TA-NaBr- MRNi (O) pivalic acid (A) acetic acid. Catalyst standard (see Table IX). Reaction conditions 2-octanone (10 ml), THF (20 tnl). acid. 100 C, 90 kg em2.

A number of ketones have been condensed with ethyl cyanoacetate by this procedure. Reactive ketones such as aliphatic methyl ketones and cyclohexanone condense with ethyl cyanoacetate much more rapidly and give better yields of alkyli-dene esters. It is advantageous with such ketones to use a lower ratio of ammonium acetate-acetic acid catalyst.1... 

Two important commercial diacids are adipic acid (hexanedioic acid) and tere-phthalic acid (benzene-1,4-dicarboxylic acid). Adipic acid is used in making nylon 66, and terephthalic acid is used to make polyesters. The industrial synthesis of adipic acid uses benzene as the starting material. Benzene is hydrogenated to cyclohexane, whose oxidation (using a cobalt/acetic acid catalyst) gives adipic acid. Terephthalic acid is produced by the direct oxidation of para-xylene in acetic acid using a cobalt-molybdenum catalyst. 

Figure 9. The change in Sh o tn the water desorption test for ETES films formed on silica using acetic acid catalyst. —O— flamed silica,...

The acetophenone XXVII was condensed with ethylcyanoacetate (ammonium acetate-acetic acid catalyst) to yield the substituted acrylonitrile XXVIII. When XXVIII was heated in ethanol with... 

For the processing of furfural in general, and for the control of furfural reactors in particular, it is desirable to have a continuous in-line measurement of the furfural concentration. For batchwise operation, this shows when the charge is exhausted, and for both batchwise and continuous operation it can show the response of the furfural concentration to the steam input, thus permitting an optimization of the furfural output. This is especially important for the ROSENLEW process, where an excess steam input blows out the acetic acid catalyst, so that there is a critical steam input beyond which the furfural output diminishes sharply. In addition, it is profitable to have a continuous record of the reactor operation, to pinpoint mistakes by the operators or other irregularities. 

In the procedure of Newkome and Fishel4-48 for the preparation of acetophenone hydrazone, a mixture of 0.1 m. of the ketone, 0.3 m. of N,N-dimethylhydrazine (MCB), 25 ml. of absolute ethanol, and 1.0 ml. of acetic acid (catalyst) is refluxed for 24hrs., during which time the colorless solution becomes bright yellow. The... 

Table 3 Performances of metal oxides as with acetic acid catalysts for condensation of HCHO ...

Figure 9. Yield of acetic acid catalysts in ethanol oxidation.

A pyrrolidine-acetic acid catalyst system was found to be superior to L-proline to catalyse these transformations as L-proline produced mixtures of... 

REACTION MIXTURE Modified Fiber Solids, Reagent, Acetic Acid, Catalyst (Ti-IP)... 

A pure perovskite phase with the composition SrBi2Ta209 and a crystal size <50 nm was formed at 1073 K from a xerogel precursor, obtained by gelation from Ta(EtO)5 and Sr-acetate and BiO-nitrate solution in methoxyethanol using an acetic acid catalyst [70]. Acetate ions act as bidentate ligands in this solution, equalizing the hydrolysis/condensation rates of Ta and other ions. 

Lifetime of Monsanto acetic acid catalyst (p. 385) over ly. 

However, the gels in this study must be treated under the temperature at which wood is not thermally degraded. Therefore, in a reaction medium of the metal alkoxide/alcohol (solvent)/acetic acid (catalyst), the moisture-conditioned wood or water-saturated wood is soaked at ambient temperature under reduced pressure or atmospheric pressure. The water present within the wood cells initiates the reaction of the hydrolysis and polycondensation of metal alkoxide. The soaked wood is subsequently treated at a temperature between 50 and 60 C for 24h, and at 105°C for another 24h to prepare wood-inorganic composites (Saka, 1992 Ogjso, 1993). 

In a study of NHC-Rh complexes aimed at developing an NHC-based alternative to the Monsanto acetic acid catalyst, Haynes and co-workers prepared [(IMe)2Rh(CO)(I)] and examined its reaction with Mel. Interestingly, even though several observed intermediates had alkyl and acyl groups cis to an NHC, reductive elimination was not observed. However, when subjected to a milder version of the industrial reaction conditions, namely 10% MeOH and 2% Mel in chlorobenzene at 120 °C under 10 atm of CO, sequential loss of the two NHCs was observed, generating the NHC-free catalyst [Rh(CO)2l2], previously employed by Monsanto. This catalyst proved to be considerably more reactive than the NHC-containing species. ... 

The zinc dust reduction of the epoxy-bromo-ether requires only a calculated amount of acetic acid catalyst. If a large quantity of acetic acid is used, the 2,3-oxide function is reduced to the corresponding olefin. 

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