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Fuels From Recycled Carbon
Published in Veera Gnaneswar Gude, Green chemistry for Sustainable Biofuel Production, 2018
Michele Aresta, Angela Dibenedetto
After this excursus on oleo-biomass, let us go back to biodiesel production. Fatty acids (FAs) had a worldwide production of 7.2 Mt in 2014 [72]. As said above, saturated FAs are ideal candidates for biodiesel, which is produced by a double acid-base esterification process (the acid process uses sulfuric acid and converts free-FAs into FAMEs: conversely, the basic process uses sodium methylate and converts glycerided into FAMEs and aqueous glycerol. A great improvement here is the use of heterogeneous bifunctional catalysts, which convert at the same time FFAs, and glycerides into FAMEs [73]. In order to eliminate excess unsaturated C=C bonds, polyunsaturated fatty acid esters can be hydrogenated into monounsaturated or saturated molecules. Also fatty alcohols can be produced by carbon-oxygen double bond hydrogenation. Furthermore, complete hydrogenation of unsaturated fatty acids derivatives or fatty alcohols can lead to the complete removal of oxygen and the formation of saturated hydrocarbons. Homogeneous or heterogeneous catalysts based on Group 8 -10 metals, such as Ni, Co, Pd, Pt,and Rh, Cu are generally used to perform the partial hydrogenation of the carbon- carbon double bond under moderate operating conditions. During hydrogenation, isomerization (regio-isomerization and cis-trans isomerization) must be taken under control as trans isomers are undesired species as they do not undergo hydrogenation.
Microwave Mediated Biodiesel Production
Published in Veera Gnaneswar Gude, Microwave-Mediated Biofuel Production, 2017
Fatty acid methyl esters can be transformed into a variety of useful chemicals, and raw materials for further synthesis, as shown in Figure 19 (Schuchardt et al. 1998). The alkanolamides, whose production consumes the major part of the methyl esters produced in the world, have a direct application as non-ionic surfactants, emulsifying, thickening and plastifying agents, etc. The fatty alcohols are applied as pharmaceutical and cosmetics additives (C16-C18), as well as lubricants and plastifying agents (C6-C12), depending on the length of their carbon chain. The isopropyl esters are also applied as plastifying agents and emollients. However, they cannot be produced in a convenient way by esterification of fatty acids, because an azeotrope formed by water and isopropanol avoids the recycling of the alcohol. Fatty acid methyl esters are further used in the manufacture of carbohydrate fatty acid esters (sucrose polyesters), which can be applied as non-ionic surfactants or edible non-calorific oils, and can be used as an alternative fuel substitute for diesel engines which is called biodiesel.
Emollient Esters and Oils
Published in Randy Schueller, Perry Romanowski, Conditioning Agents for Hair and Skin, 2020
John Carson, Kevin F. Gallagher
One major factor in the manufacture of esters is the cost of the respective fatty acids versus fatty alcohols. In most cases we find that the lauric, myristic, palmitic, and stearic fatty acids are significantly cheaper than their counterpart alcohols. This is because the fatty alcohols are usually produced by the reduction of the acid group to an alcohol. Therefore, it is generally less expensive to produce an ester from a low-molecular-weight alcohol and a fatty acid than from a higher-molecular-weight fatty alcohol and a small acid.
Hydrodeoxygenation of stearic acid using Mo modified Ni and Co/alumina catalysts: Effect of calcination temperature
Published in Chemical Engineering Communications, 2020
Pankaj Kumar, Sunil K. Maity, Debaprasad Shee
The wt% of C18-OH was significant during the initial reaction time. This result indicates that the reduction of stearic acid is the initial reaction step (Figure S5). The fatty acid generally undergoes sequential reduction to the corresponding fatty alcohol through an intermediate fatty aldehyde. The fatty acids are adsorbed on the catalyst surface through C = O and C-O bonds of the carboxylic acid group. Simultaneously, molecular hydrogen is dissociatively chemisorbed on the metallic sites (Ni, Co, or alloy) forming the respective metal hydride. The hydride transfer to the electron deficient carbon atom of the COOH group reduces fatty acid to the corresponding fatty aldehyde with the formation of one water molecule. A small amount of fatty aldehyde (C17-CHO) was also noticed over bi-metallic catalysts (Peng et al., 2013). Further reduction of the fatty aldehyde to the corresponding fatty alcohol follows a similar reaction mechanism.
Restricted substances for textiles
Published in Textile Progress, 2022
Arun Kumar Patra, Siva Rama Kumar Pariti
Many substitutes for NPEO (nonylphenol ethoxylates) and OPEO (octylphenl ethoxylates) have been developed and are commercialized. One example is the alcohol ethoxylates. These are composed of hydrophobic fatty alcohols combined with various numbers of ethoxylate groups. They are very good surface active agents and being easily biodegradable, do not cause any problem in the disposal of effluents (Vaidya & Trivedi, 1976). The general reaction in their preparation is