Q2. Why is lignin used as an alternative to fossil resources?
Due to its high aromatic content, lignin has great potential to function as an alternative to non-renewable fossil resources, for the production of aromatic fine chemicals.
Q3. What is the way to obtain branched ester groups?
In addition, by the use of fatty acids that contain multiple unsaturations, branched ester groups can be obtained, although with a low yield.
Q4. What is the role of the aromatic group in the formation of ruthenium?
It was proposed that the aromatic group acts as a ligand for the ruthenium, after reduction of the ruthenium(III) halide precursors, followed by the formation of allyl complexes of the fatty acid chains.
Q5. What is the main challenge in the transformation of biomass derived feedstocks?
One particular challenge in the transformation of biomass derived feedstocks is the co-existence of competing pathways that lead to decreased product yields and selectivities at the temperatures usually applied for defunctionalisation and/or depolymerisation.
Q6. What is the way to convert linoleic acid to CLAs?
Using mild reaction conditions, many metal precursors catalyse the conversion of linoleic acid, or methyl linoleate, to CLAs, although tin based promoters have to be employed for an efficient conversion (Scheme 16).
Q7. What is the method for cleaving aryl ethers?
The effective cleavage of electron rich aryl ethers could also be achieved using nickel precursors without stabilising ligands, yielding nickel nanoparticles (Scheme 10).
Q8. What is the role of glycerol in the production of food additives?
In addition to the recent interest for biodiesel production, glycerol and the fatty acids or methyl esters thereof, obtained after ester hydrolysis, have many applications in for example, the production of soaps, lubricants, coatings, plastics and food additives.
Q9. What is the chemical reaction that gives 2,5-furandicarboxylic acid?
The oxidation of HMF gives 2,5-furandicarboxylic acid, which is under investigation as a replacement for phthalic acid in polyesters, like PET.46 A number of C–C bond forming reactions have been reported to further add functionality to HMF.
Q10. What is the recent research on ruthenium precursors?
A later study showed that, using hydrogen gas, the ruthenium–xantphos complex is capable of the direct hydrogenolysis of the β–O–4 motif containing a ketone at the benzylic carbon instead of an alcohol.63 Different catalysts, consisting of alternative combinations of ruthenium precursors and phosphine ligands, have been reported for the conversion of similar model compounds.
Q11. What are the effective methods for converting fatty acids to CLAs?
119 Various methods exist, which provide CLAs from unconjugated fatty acids, using alkaline processes, biocatalysts, photocatalysts and metal catalysts.
Q12. Why are unsaturated fatty acids of importance for use as renewable resources?
Among these, unsaturated fatty acids are of most importance for use as renewable resources, because the double bond provides a convenient handle for further chemical valorisation.
Q13. What is the catalyst for oxidation of a lignin model compound?
84Stahl and coworkers screened a range of catalysts for the selective oxidation of either the primary (1°) γ-alcohol or the secondary (2°) α-alcohol of a lignin model compound (Scheme 13).85 Copper/TEMPO derived oxidation catalysts showed good primary alcohol selectivity, while palladium, iron and chromium catalysts selectively oxidized the secondary alcohol.
Q14. What is the active complex used in the synthesis of insect pheromones?
The most active complex (TON close to 1000, Scheme 18b) was used in the synthesis of several insect pheromones, from fatty acid derived starting materials.
Q15. What is the useful method for the synthesis of Z-alkene containing products?
131 The Z-selective fatty acid type intermediates were obtained in excellent isolated yields from cross-metathesis reactions of alcohols, like oleyl alcohol, or 11-eicosenol with 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-decene and 1,4-hexadiene establishing this methodology as a very useful synthetic tool for the synthesis of Z-alkene containing products from fatty acid derived substrates.
Q16. What is the process of depolymerisation of biomass?
The valorisation of biomass or biomassderived feedstocks firstly requires the selective depolymerisation of complex, highly oxygenated biopolymers or oligomers followed by selective defunctionalisation (Fig. 1).7
Q17. What is the common reaction used to catalyze ruthenium precursors?
a wider variety of ruthenium precursors and phosphine ligands (e.g. triphenylphosphine) have been successfully applied in the same reaction, when a mixture of potassium t-amylate and ethylacetate was additionally applied.
Q18. How could the cleavage be coupled to a second hydrogen autotransfer process?
In this case, the cleavage could also be coupled to a second hydrogen autotransfer process, by applying a subsequent α-alkylation step with primary alcohols.