Alcohol continued synthetic

Sasol produces synthetic fuels and chemicals from coal-derived synthesis gas. Two significant variations of this technology have been commercialized, and new process variations are continually under development. Sasol One used both the fixed-bed (Arge) process, operated at about 240°C, as weU as a circulating fluidized-bed (Synthol) system operating at 340°C. Each ET reactor type has a characteristic product distribution that includes coproducts isolated for use in the chemical industry. Paraffin wax is one of the principal coproducts of the low temperature Arge process. Alcohols, ketones, and lower paraffins are among the valuable coproducts obtained from the Synthol process. 

In 1991, the relatively old and small synthetic fuel production faciHties at Sasol One began a transformation to a higher value chemical production facihty (38). This move came as a result of declining economics for synthetic fuel production from synthesis gas at this location. The new faciHties installed in this conversion will expand production of high value Arge waxes and paraffins to 123,000 t/yr in 1993. Also, a new faciHty for production of 240,00 t/yr of ammonia will be added. The complex will continue to produce ethylene and process feedstock from other Sasol plants to produce alcohols and higher phenols. 

Other typical pyrotechnic fuels include charcoal, sulfur, boron, siUcon, and synthetic polymers such as poly(vinyl alcohol) and poly(vinyl chloride). Extensive use has been made of natural products such as starches and gums, and the use of these materials continues to be substantial in the fireworks industry. MiUtary pyrotechnics have moved away from the use of natural products due to the inherent variabiUty in these materials depending on climatic conditions during the growth of the plants from which the compounds are derived. 

Synthetic activity associated with the carbonyl-ene reaction is extensive. During the past decade, the trend has been to perform these reactions in the presence of a Lewis acid in an enantioselective fashion. Efforts to find a general catalyst that affords homoallylic alcohols in high yields and enantioselectivities are continual. The synthetic utility of this reaction has been validated by its application to the synthesis of a number of natural products (see Section 10.12.6) and many structurally novel motifs that have found a place in drug discovery vide infra). It is the latter application that has resulted in research efforts aimed at large-scale production of carbonyl-ene adducts. 

New applications continue to demonstrate the enormous versatility of RCM for organic synthesis. Examples include triple ring closing (Eq. 48) and alkyne metathesis, an example being that of cross-metathesis that provides an efficient synthetic strategy for prostaglandin E2 (Eq. 49). Amines and alcohols deactivate metathesis catalysts, but their protection as ethers, esters, and amides allows them to be incorporated into the designated transformation. 

To a soln of the methyl alkylphosphonate 50 (0.5 mmol), the alcohol 59 (0.75 mmol), and Ph3P (0.75 mmol) dissolved in anhyd THF (5mL) were added DIAD (0.75 mmol) and TEA (5 mmol), followed by the a-hydroxy acid (lmmol). Upon completion of the condensation reaction, TMSBr (1.5 mmol) was added and stirring continued for an additional 1 h. The mixture was diluted with E O (10 mL) and extracted with 5% NaHC03 (2xl0mL). The aqueous phase was washed with E O (3 x 10mL), acidified to pH 2 with coned HC1, and extracted with EtOAc (3 x lOmL). The EtOAc phase was dried (MgS04), filtered, and concentrated under reduced pressure. This material was suitable for additional synthetic steps or could be isolated in pure form as the 1-adamantanamine salt from E O or hexane. Characterization of (R,5)-Z-Valp-(0)-D-Val-OMe (60 R1 = R2=iPr), isolated in 69% yield after 4h reaction 31P NMR (5) 24.23, 23.94. 

This synthetic methodology has been extended by the development of an efficient series of reactions that can transform one allylic alcohol into a second, which is two carbons longer than the first. Repetition of the reaction sequence can, in principle, be continued to any desired chain length. 

The partial oxidation of alcohols, to afford carbonyl or carboxylic compounds, is another synthetic route of high industrial interest For this, scC02 was investigated as a reaction medium for the aerobic oxidation of aliphatic, unsaturated, aromatic and benzylic acids with different catalytic systems, mainly based on the use of noble metals, both in batch [58-64] and in continuous fixed-bed reactors [65-70]. In this context, very promising results have been obtained when studying the catalytic activity of supported palladium and gold nanoparticles in the oxidation of benzyl alcohol to benzaldehyde these allowed conversions and selectivities in excess of 90% to be achieved [71-73]. 

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