Butanal, 2-ethyl-1-hexanol from

Example 6.5. Olefin hydroformylation with phosphine-substituted cobalt hydrocarbonyl catalyst [30], The pathway 6.9 of olefin hydroformylation with the "oxo" catalyst, HCo(CO)4, has been shown in Example 6.2 in Section 6.3. For phosphine-substituted catalysts, HCo(CO)3Ph (Ph = organic phosphine), the pathway olefin — aldehyde is essentially the same. However, these catalysts also promote hydrogenation of aldehyde to alcohol (Examples 7.3 and 7.4) and of olefin to paraffin (Example 7.5). Moreover, straight-chain primary aldehydes under the conditions of the reaction undergo to some extent condensation to aldol, which is subsequently dehydrated and hydrogenated to yield an alcohol of twice the carbon number (e.g., 2-ethyl hexanol from n-butanal see Section 11.2). The entire reaction system is... 

Outline a synthesis of 2 ethyl 1 hexanol from butanal... 

The use of alkali metal oxide catalysts for aldol condensation reactions has been examined for the production of 2-ethylhexenal from butanal [34]. When coupled to a hydrogenation catalyst the system can produce the plasticizer alcohol 2-ethyl-hexanol directly. When isobutyraldehyde was used as the feed to a silica-supported sodium oxide catalyst, no products were formed but a significant amount of carbon was deposited on the catalyst and in the reactor (Scheme 21.2). 

Our results showed that the flavour profile of peas was affected by market class, cultivar location, and crop year. The highest total volatile compound (TVC) was observed in cultivars from marrowfat-market class. Crops grown in Meath Park location had the highest TVC. Furthermore, different volatile compounds were identified in pea cultivars. In both crop years, cultivars from the green-market class had the highest mean values of esters and hydrocarbons, whereas the highest value of alcohols was observed for the marrowfat-market class, and the dun-market class had the highest mean values of ketones and pyrazine. 3-Methyl-butanol, 1-propanol, 2-ethyl-hexanol, 3-methyl-butanal, trichloromethane, 2-butanone, dimethyl sulfide, ethyl acetate and 2,3-diethyl-5-methyl pyrazine were the most abundant volatile compounds observed in the pea cultivars. 

The carbon skeleton of 2-ethyl-1-hexanol is the same as that of the aldol condensation product derived from butanal. Hydrogenation of this compound under conditions in which both the carbon-carbon double bond and the carbonyl group are reduced gives 2-ethyl-l-hexanol. 

Formation of aldehydes by the reaction of alkene, CO and H2 catalysed by Co2(CO)8 was discovered by Rolen in 1938 [25]. This is the 1,2-addition of H and CHO to alkenes, and hence called hydroformylation or the oxo reaction. Production of butanal, (33) from propylene as a main product is an important industrial process. Aldol condensation of butanal, followed by hydrogenation affords 2-ethyl-1-hexanol (34), which is converted to phthalate, and used as a plasticizer of poly(vinyl chloride). 

Ethyl-1-hexanol, used in the synthesis of di(2-ethylhexyl) phthalate plasticizer, is made commercially from butanal. Show the likely synthesis route. 

Ethyl-1-hexanol is used for the synthesis of the sunscreen octyl p-methoxycinnamate. (See Chemical Connections 14A.)This primary alcohol can be synthesized from butanal by the following series of steps ... 

Today the installed hydroformylation capacity worldwide is more than 7.5 Mio tons per year (Baerns et al., 2006). The most important feedstock is propene, with the products n-butyraldehyde and iso-butyraldehyde (Scheme 6.14.3). The most important single product from propene hydroformylation is 2-ethyl-l-hexanol (>50% of the n-butyraldehyde production), the aldol condensation product obtained from n-butanal, which is an important plasticizer alcohol. After esterification with phthalic anhydride, dioctyl phthalates plasticizers are obtained that are used mainly in poly(vinyl chloride) plastics. 

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