Alcohol conversion

An example of a specialty olefin from an amyl alcohol is Phillips Petroleum s new process for 3-methyl-1-butene (used in the synthesis of pyrethroids) from the catalytic dehydration of 3-methyl-1-butanol (21,22). The process affords 94% product selectivity and 94% alcohol conversion at 310°C and 276 kPa (40 psig). 

Several other oxidants can be used to effect the borane to alcohol conversion. Oxone (2K2S05 KHS04 K2S04) has been recommended for oxidations done on a... 

It is concluded that the occupation of the step and kink sites plays a crucial role in the promotion of the Pt catalyst. The cyclic voltammetry results can be used to explain the conversion trends observed in Figure 2. For unpromoted 5%Pt/C the Pt step and kink sites are unoccupied and available for adsorption of reactant and oxidant species. During reaction these sites facilitate premature catalyst deactivation due to poisoning by strongly adsorbed by-products (5) and (or) the formation of a surface oxide layer (6). The 5%Pt,0.5%Bi/C catalyst has a portion of these Pt step and kink sites occupied and the result is a partial reduction in the catalyst deactivation and a consequent increase in alcohol conversion. As the Bi level is increased to lwt.% almost all of the Pt step and kink sites are occupied and the result is a catalyst with high activity. As more Bi is introduced onto the catalyst surface a bulk Bi phase is formed. Since the catalyst activity is maintained it is speculated that the bulk Bi phase is not involved in the catalytic cycle. 

The optimal activation temperature of zeolites in the range 300-600°C was determined in preliminary experiments. The temperature 500°C was selected for all catalysts but for H-MFI-28 (400°C). DSC and TG analyses show that at 500°C, NH4+ forms of zeolites are totally converted into H-MOR-20 and H-FER-20, respectively. Table 2 shows alcohol conversion (XR0H), selectivity to ether (SROr), to olefin (Soiefm) and branched ethers (SrOR>), and ether yield (YROr) at 180°C after 6 h reaction course. 

Alcohols, conversion to alkyl halides with triphcnylphosphine-halogen adducts, 48, 53 synthesis of equatorial, 47, 19 Aldehydes, aromatic, synthesis of, 47, 1... 

Figure 8.2 Benzyl alcohol conversion as function of the rate of H202 addition in the presence of silica-entrapped TPAP. (Reproduced from ref. 2, with permission.)...

Alcohol Conversion to octalins (%) Octalins formed (mole %) ... 

There is a rather important difference between chemical reductions using complex metal hydrides and enzymic reductions involving NADH, and this relates to stereospecificity. Thus, chemical reductions of a simple aldehyde or ketone will involve hydride addition from either face of the planar carbonyl group, and if reduction creates a new chiral centre, this will normally lead to a racemic alcohol product. Naturally, the aldehyde primary alcohol conversion does not create a chiral centre. 

Conjugate addition to 1 proceeded across the open face of the bicyclic system to give an enolate, condensation of which with the enantiomerically-pure aldehyde 8 gave the enone 9. Conjugate reduction of the enone also removed the benzyl ether, to give the alcohol. Conversion of the alcohol to the azide gave 10. Ozonolysis followed by selective reduction then gave 2. 

Oxidation of Alcohols. Conversion of alcohols to aldehydes and acids has received considerably less attention. The chemistry of this process has been explored primarily with respect to formation of stable hydrides of Pt, Ir, Ru, and Os (7, 8) (Reaction 4). 

Preparation.l Dialkyl acetals of DMF are generally prepared by transacetal-ization of the dimethyl or diethyl acetal, but this reaction is not useful in the case of the di-r-butyl acetal. Replacement of one methoxy group of DMF dimethyl acetal occurs on refluxing in f-butyl alcohol conversion to the dw-butyl acetal is effected in the presence of 2,4,6-tri-f-butylphenol (equation I). 

HYD/HDO+I and HDO/I ratios for allylic alcohols conversions comparison with allylic and vinylic ethers... 

The reaction of tert-butyl alcohol and methanol to form MTBE is also catalyzed by heteropoly compounds (221-223). A relationship was found between the amount of pyridine sorbed in or on heteropoly compounds and tert-butyl alcohol conversion (221). The dependence of the rate on methanol partial pressure resembles that for the absorption of methanol in the bulk, suggesting pseudoliquid phase behavior (223). 

Alcohol [C6H6]/[ROH] Temperature (°C) Contact time (s) Alcohol Conversion (%)... 

The non-reducing trisaccharide planteose was first isolated22 by Wattiez and Hans from seeds of Plantago major and P. ovata. Extraction of de-fatted seeds of P. ovata with 70% alcohol, conversion of the sugars in the extract to their barium complexes, removal of the barium with sulfuric acid, and extraction of the evaporated sirup with 85% alcohol, gave solutions from which planteose dihydrate gradually crystallized it has m.p. 123-4°, [ ]d + 125.5° (in water). 

---