Bio-Based Solvents and Gasoline Components from Renewable 2,3-Butanediol and 1,2-Propanediol: Synthesis and Characterization

Abstract

In this study approaches for chemical conversions of the renewable compounds 1,2-propanediol (1,2-PD) and 2,3-butanediol (2,3-BD) that yield the corresponding cyclic ketals and glycol ethers have been investigated experimentally. The characterization of the obtained products as potential green solvents and gasoline components is discussed. Cyclic ketals have been obtained by the direct reaction of the diols with lower aliphatic ketones (1,2-PD + acetone → 2,2,4-trimethyl-1,3-dioxolane (TMD) and 2,3-BD + butanone-2 → 2-ethyl-2,4,5-trimethyl-1,3-dioxolane (ETMD)), for which the ΔH0r, ΔS0r and ΔG0r values have been estimated experimentally. The monoethers of diols could be obtained through either hydrogenolysis of the pure ketals or from the ketone and the diol via reductive alkylation. In the both reactions, the cyclic ketals (TMD and ETMD) have been hydrogenated in nearly quantitative yields to the corresponding isopropoxypropanols (IPP) and 3-sec-butoxy-2-butanol (SBB) under mild conditions (T = 120–140 °C, p(H2) = 40 bar) with high selectivity (>93%). Four products (TMD, ETMD, IPP and SBB) have been characterized as far as their physical properties are concerned (density, melting/boiling points, viscosity, calorific value, evaporation rate, Antoine equation coefficients), as well as their solvent ones (Kamlet-Taft solvatochromic parameters, miscibility, and polymer solubilization). In the investigation of gasoline blending properties, TMD, ETMD, IPP and SBB have shown remarkable antiknock performance with blending antiknock indices of 95.2, 92.7, 99.2 and 99.7 points, respectively.

In-silico-assisted derivatization of triarylboranes for the catalytic reductive functionalization of aniline-derived amino acids and peptides with H2

“…Finally, increasing the H 2 pressure to 60 atm resulted in the formation of 3aa in 95% yield after the period of 24 h. The use of TMD did not furnish any 3aa . It should be noted that MTHP can be easily separated from water (its solubility in H 2 O is ~1.5 wt%) and removed under reduced pressure due to its strong hydrophobicity and low heat of vaporization, although its employment as a greener solvent has been limited in organic synthesis compared with the use of 2-MeTHF and CPME 32 , 33 . Moreover, to clarify the benefit of using MTHP over THF, we compared the activation energies for the heterolytic cleavage of H 2 by the combination of B 4b and THF or MTHP at the ω B97X-D/6-311+G(d,p)// ω B97X-D/6-31G(d,p) level (Fig.…”

“…In terms of toxicity, the solvent THF, which also acts here as a Lewis base to generate FLPs with boranes (Fig. 1B), should be replaced with a less hazardous chemical 32,33 . Given the central role of the reductive alkylation of amines using carbonyl compounds in the synthesis of, e.g., pharmaceuticals, bio-active molecules, and agrochemicals [34][35][36] , the development of a straightforward and greener protocol for derivatizing amino acids and peptides would be worthwhile.…”

In-Silico-Assisted Derivatization of Triarylboranes for the Catalytic Reductive Functionalization of Amino Acids with H2

“…It should be noted that MTHP can be easily separated from water (its solubility in H2O is ~1.5 wt%) and removed under reduced pressure due to its strong hydrophobicity and low heat of vaporization, although its employment as a greener solvent has been limited in organic synthesis compared with the use of 2-MeTHF and CPME. 32,33 Moreover, to clarify the benefit of using MTHP over THF, we compared the activation energies for the heterolytic cleavage of H2 by the combination of B 4b and THF or MTHP at the B97X-D/6-311+G(d,p)//B97X-D/6-31G(d,p) level (Figure 5B). A possible transition state was found in both cases, and that in the case of MTHP was found to be more stabilized (TSMTHP = +21.8 kcal mol −1 ) than that in the case involving THF (TSTHF = +23.2 kcal mol −1 ).…”

“…In terms of toxicity, the solvent THF, which also acts here as a Lewis base to generate FLPs with boranes, should be replaced with a less hazardous chemical. 32,33 Given the central role of the reductive alkylation of amines using carbonyl compounds in the synthesis of e.g. pharmaceuticals, bio-active molecules, and agrochemicals, 34−36 the development of a straightforward and greener protocol for derivatizing amino acids and peptides would be worthwhile.…”

Editorial for the “Green Chemistry” Section in the Journal Molecules: Focus on Solvents

“…Tightening chemical regulation and the desire for a lessened dependency on fossil feedstocks encourages the development of bio-based solvents. Samoilov and co-workers report the synthesis and comprehensive characterisation of cyclic ketals and glycol ethers from bio-based diols [1]. The question of identifying appropriate applications for new solvents has been addressed by Sels et al [2].…”