6250-70-0Relevant articles and documents
Single-step access to long-chain α,ω-dicarboxylic acids by isomerizing hydroxycarbonylation of unsaturated fatty acids
Goldbach, Verena,Falivene, Laura,Caporaso, Lucia,Cavallo, Luigi,Mecking, Stefan
, p. 8229 - 8238 (2016)
Dicarboxylic acids are compounds of high value, but to date long-chain α,ω-dicarboxylic acids have been difficult to access in a direct way. Unsaturated fatty acids are ideal starting materials with their molecular structure of long methylene sequences and a carboxylate functionality, in addition to a double bond that offers itself for functionaliza-tion. Within this paper, we established a direct access to α,ω-dicarboxylic acids by combining isomerization and selective terminal carbonylation of the internal double bond with water as a nucleophile on unsaturated fatty acids. We identified the key elements of this reaction: a homogeneous reaction mixture ensuring sufficient contact between all reactants and a catalyst system allowing for activation of the Pd precursor under aqueous conditions. Experiments under pressure reactor conditions with [(dtbpx)Pd(OTf)2] as catalyst precursor revealed the importance of nucleophile and reactant concentrations and the addition of the diprotonated diphosphine ligand (dtbpxH2)(OTf)2 to achieve turnover numbers >120. A variety of unsaturated fatty acids, including a triglyceride, were converted to valuable long-chain dicarboxylic acids with high turnover numbers and selectivities for the linear product of >90%. We unraveled the activation pathway of the PdII precursor, which proceeds via a reductive elimination step forming a Pd0 species and oxidative addition of the diprotonated diphosphine ligand, resulting in the formation of the catalytically active Pd hydride species. Theoretical calculations identified the hydrolysis as the rate-determining step. A low nucleophile concentration in the reaction mixture in combination with this high energetic barrier limits the potential of this reaction. In conclusion, water can be utilized as a nucleophile in isomerizing functionalization reactions and gives access to long-chain dicarboxylic acids from a variety of unsaturated substrates. The activity of the catalytic system of hydroxycarbonylation ranks as one of the highest achieved for isomerizing functionalizations in combination with a high selectivity for the linear product.
Long-chain linear C19 and C23 monomers and polycondensates from unsaturated fatty acid esters
Stempfle, Florian,Quinzler, Dorothee,Heckler, Ilona,Mecking, Stefan
, p. 4159 - 4166 (2011)
Isomerizing alkoxycarbonylation of methyl oleate and ethyl erucate, respectively, yielded dimethyl 1,19-nonadecanedioate and diethyl 1,23-tricosanedioate in >99% purity. With [κ2-(P P)Pd(OTf)][OTf] as a defined catalyst precursor (PP = 1,2-bis[(di-tert- butylphosphino)methyl]benzene) the reaction can be carried out without the need for additional added diphosphine. Saponification of the diesters yielded 1,19-nonadecanedicarboxylic acid and 1,23-tricosanedicarboxylic acid in >99% purity. By ruthenium-catalyzed reduction of the diesters with H2, 1,19-nonadecanediole and 1,23-tricosanediole were formed in high yield and purity (>99%). From the latter, 1,19-nonadecanediamine and 1,23-tricosanediamine were generated. Polyesters with commercially available shorter-chain petrochemical or renewable diols exhibit high melting points due to the crystallizable long-chain methylene segments from the dicarboxylic acid component, e.g., poly[1,6-hexadiyl-1,23-tricosanedioate] Tm 92, Tc 75 °C. Thermal properties of novel long-chain polyamides are reported.
A new route to α,ω-diamines from hydrogenation of dicarboxylic acids and their derivatives in the presence of amines
Shi, Yiping,Kamer, Paul C. J.,Cole-Hamilton, David J.
, p. 5460 - 5466 (2017/11/22)
A new and selective route for the synthesis of polymer precursors, primary diamines or N-substituted diamines, from dicarboxylic acids, diesters, diamides and diols using a Ru/triphos catalyst is reported. Excellent conversions and yields are obtained under optimised reaction conditions. The reactions worked very well using 1,4-dioxane as solvent, but the greener solvent, 2-methyl tetrahydrofuran, also gave very similar results. This method provides a potential route to converting waste biomass to value added materials. The reaction is proposed to go through both amide and aldehyde pathways.
