517
prominence. Microbial routes for 1,4-BDO using engineered E. coli microorganisms have been developed up to demonstration scale [114–116]. Major applications
of 1,4-BDO include synthesis of gamma butyrolactone, use as solvents and in the
manufacture of plastics, fibres and polyurethanes.
C4 and C5 alcohols and diols are highly valuable chemical intermediates used as
monomers in the production of polyesters, polyurethanes and polyethers, as fuel
additives to boost gasoline octane number and as versatile solvents for various
applications. Several process options for the synthesis of C 5+ alcohols/higher alcohols/fatty alcohols are available. Some of the processes developed earlier include
[56, 117]:
• Hydrogenation of fatty acids and fatty acid esters derived from vegetable and
animal fats and oils.
• Conversion of ethylene with Al alkyls, Al (CH 2 CH 3 ) 3 to a mixture of linear, primary alcohols (Ziegler process).
• Hydroformylation of olefins with CO and H 2 to a mixture of branched and
unbranched aldehydes and subsequent hydrogenation to the corresponding
alcohols.
• Oxidation of paraffins with boric acid to linear, secondary alcohols.
• Condensation of primary alcohols C 2 –C 4 with basic catalysts to α-branched and
linear, dimeric alcohols based on Guerbet chemistry [118].
Of recent, advances in the development of biomass conversion processes have
brought into focus more process options:
– Oligomerization of ethylene derived from bioethanol and bio-methanol conversion through MTO to higher carbon number olefins followed by oxo synthesis
and hydrogenation [119–121].
– Condensation of biomass-derived methanol and ethanol to higher alcohols via
Guerbet chemistry [118, 122], self-condensation and cross-condensation
reactions.
Biomass-derived platform chemicals/intermediates have been used as raw materials for the sustainable production of C 4 –C 5 alcohols and diols. A comprehensive
review by Sun et al. [123] describes in detail the processes and catalysts developed
and other features for the synthesis of C 4 –C 5 alcohols and diols from various
biomass- based raw materials, like succinic acid, dialkyl succinates, γ-butyrolactone,
levulinic acid and alkyl levulinates, γ-valerolactone and furfural and its derivatives.
Since many years, syngas has been another rich source for the production of
higher alcohols and versatile in application, since it can be obtained from different
raw materials, both fossil and biomass based, with several syngas conversion options
therein. An extensive review, by Luk et al. [124], covering various process options
for the conversion of syngas to higher alcohols, the catalysts and structure-activity
correlations therein and the process features, (Fig. 10) along with the details on the
applications of C 6 –C 22 long-chain alcohols [125] as feedstocks and chemical intermediates and in polymers, surfactants and detergent industries, has been published.
Catalytic Conversion of Alcohols into Value-Added Products
prominence. Microbial routes for 1,4-BDO using engineered E. coli microorganisms have been developed up to demonstration scale [114–116]. Major applications
of 1,4-BDO include synthesis of gamma butyrolactone, use as solvents and in the
manufacture of plastics, fibres and polyurethanes.
C4 and C5 alcohols and diols are highly valuable chemical intermediates used as
monomers in the production of polyesters, polyurethanes and polyethers, as fuel
additives to boost gasoline octane number and as versatile solvents for various
applications. Several process options for the synthesis of C 5+ alcohols/higher alcohols/fatty alcohols are available. Some of the processes developed earlier include
[56, 117]:
• Hydrogenation of fatty acids and fatty acid esters derived from vegetable and
animal fats and oils.
• Conversion of ethylene with Al alkyls, Al (CH 2 CH 3 ) 3 to a mixture of linear, primary alcohols (Ziegler process).
• Hydroformylation of olefins with CO and H 2 to a mixture of branched and
unbranched aldehydes and subsequent hydrogenation to the corresponding
alcohols.
• Oxidation of paraffins with boric acid to linear, secondary alcohols.
• Condensation of primary alcohols C 2 –C 4 with basic catalysts to α-branched and
linear, dimeric alcohols based on Guerbet chemistry [118].
Of recent, advances in the development of biomass conversion processes have
brought into focus more process options:
– Oligomerization of ethylene derived from bioethanol and bio-methanol conversion through MTO to higher carbon number olefins followed by oxo synthesis
and hydrogenation [119–121].
– Condensation of biomass-derived methanol and ethanol to higher alcohols via
Guerbet chemistry [118, 122], self-condensation and cross-condensation
reactions.
Biomass-derived platform chemicals/intermediates have been used as raw materials for the sustainable production of C 4 –C 5 alcohols and diols. A comprehensive
review by Sun et al. [123] describes in detail the processes and catalysts developed
and other features for the synthesis of C 4 –C 5 alcohols and diols from various
biomass- based raw materials, like succinic acid, dialkyl succinates, γ-butyrolactone,
levulinic acid and alkyl levulinates, γ-valerolactone and furfural and its derivatives.
Since many years, syngas has been another rich source for the production of
higher alcohols and versatile in application, since it can be obtained from different
raw materials, both fossil and biomass based, with several syngas conversion options
therein. An extensive review, by Luk et al. [124], covering various process options
for the conversion of syngas to higher alcohols, the catalysts and structure-activity
correlations therein and the process features, (Fig. 10) along with the details on the
applications of C 6 –C 22 long-chain alcohols [125] as feedstocks and chemical intermediates and in polymers, surfactants and detergent industries, has been published.
Catalytic Conversion of Alcohols into Value-Added Products