Conversion of fatty acid methyl esters into dibasic esters by metathesis and their lubricant properties.

Biodiesel plants are struggling to find value added applications for fatty acid methyl esters (FAME). One option for FAME valorization would be dibasic esters, which can be transesterified with 2-ethylhexyl (2EH) or other alcohols to produce lubricant basestocks and achieve the most widespread viscosity grades VG46 and VG32. Biocatalytic, metathesis and other synthetic pathways are available to produce dibasic esters. Using a ruthenium-based catalyst, methyl oleate was converted into monounsaturated dibasic ester by metathesis and reached VG22 after transesterification with 2EH in this investigation. Synthesized 2EH esters of other dibasic acids showed distinct viscometric trends. Their correlation implied that FAME from gondoic and erucic acids should result in VG32 and VG46 respectively, if converted into 2EH dibasic esters. Pour points demonstrated excellent low temperature fluidity and resistance to heat thinning when monounsaturation was retained. Oxidative stability properties remained acceptable, volatility was lower than that of VG46 mineral oils. Mixed alcohols, acids and esters can also be used for meeting VG specifications or achieving higher biobased contents. Currently petrochemical ester basestocks dominate in high performance hydraulic fluids (HF). However, fractionation of FAME into high-erucic/gondoic esters in biodiesel plants can produce a valuable biobased feedstock for large volume manufacture of HF and other lubricants.

Coupling Rhodium-Catalyzed Hydroformylation of 10-Undecenitrile with Organic Solvent Nanofiltration: Toluene Solution versus Solvent-Free Processes.

Intensification of the rhodium-catalyzed hydroformylation process to produce 12-oxo-dodecanenitrile from biosourced 10-undecenitrile was performed by coupling the reaction with organic solvent nanofiltration (OSN) for the recycling of the expensive Rh catalyst and the ligands. Four phosphorus-based ligands were compared with respect to their catalytic performance and rejection in OSN. Biphephos showed the best compromise and up to 3 reaction-OSN cycles were performed in toluene. A good recycling of the catalytic system was evidenced arising from the OSN (up to 88 % rejection). In order to develop a greener process, a similar approach was achieved in bulk (i. e. solvent-free medium), thus proving the catalyst recycling feasibility but also that the optimal OSN conditions are not the same as for toluene. Finally, integration of OSN in the overall production process is discussed, aiming at the proposal of a hybrid separation process involving a combination of OSN and distillation for an energy-efficient separation step.

Early-Stage Capital Cost Estimation of Biorefinery Processes: A Comparative Study of Heuristic Techniques.

Biorefineries offer a promising alternative to fossil-based processing industries and have undergone rapid development in recent years. Limited financial resources and stringent company budgets necessitate quick capital estimation of pioneering biorefinery projects at the early stages of their conception to screen process alternatives, decide on project viability, and allocate resources to the most promising cases. Biorefineries are capital-intensive projects that involve state-of-the-art technologies for which there is no prior experience or sufficient historical data. This work reviews existing rapid cost estimation practices, which can be used by researchers with no previous cost estimating experience. It also comprises a comparative study of six cost methods on three well-documented biorefinery processes to evaluate their accuracy and precision. The results illustrate discrepancies among the methods because their extrapolation on biorefinery data often violates inherent assumptions. This study recommends the most appropriate rapid cost methods and urges the development of an improved early-stage capital cost estimation tool suitable for biorefinery processes.

Cross-metathesis of biosourced fatty acid derivatives: a step further toward improved reactivity.

The improved catalytic conversion of bioresources, namely unsaturated fatty acid derivatives, is presented. The targeted reaction is ruthenium-catalyzed cross-metathesis with functionalized olefins (α,ß-unsaturated esters), that affords shorter diesters. These can be used as biosourced (pre)monomers for the production of polyesters. It is demonstrated that switch from terminal to internal cross-metathesis partners (that is, from methyl acrylate to methyl crotonate) allows use of ppm-level catalyst loadings, while retaining high productivity and selectivity. This was exemplified on a commercial biosourced fatty acid methyl esters mixture, using minimal purification of the substrate, on a 50 g scale. We propose that this improved catalytic behavior is due to the sole presence of more stable alkylidene intermediates, as the notoriously unstable ruthenium methylidene species are not formed using an internal functionalized olefin.

Ammoniation-dehydration of fatty acids into nitriles: heterogeneous or homogeneous catalysis?

Fatty nitriles have lately become of interest in the framework of biofuels and for the valorization of the oil part of biomass to form fine chemicals or polymers. The production of long-chain fatty nitriles by the direct reaction of acids with NH3 has not been extensively studied, although several catalysts have been developed and published as patents. The characterization of this reaction with and without catalyst is, to the best of our knowledge, performed for the first time in this study. Several catalysts with various acid-base features were tested, and the best catalysts at 250 °C (Zn- and In-based catalysts) were further studied. Catalytically active forms and models are proposed for the Zn- and In-based catalysts, and the kinetic parameters for the amide to nitrile reaction are evaluated.

Versatile one-pot synthesis of supramolecular plastics and self-healing rubbers.

We propose a strategy to obtain through a facile one-pot synthesis a large variety of supramolecular materials that can behave as differently as associating low-viscosity liquids, semicrystalline or amorphous thermoplastics, viscoelastic melts or rubbers. Such versatility is achieved thanks to simultaneous synthesis of branched backbones and grafting of associating units. This contrasts with usual synthetic pathways that rely on grafting functional groups on preprepared backbones. We use oligocondensation of fatty di- and triacids with diethylenetriamine and finely tune the molecular weight and degree of branching by end-capping some acid groups before condensation by reaction with aminoethylimidazolidone. Supramolecular assembly is formed thanks to complementary and self-complementary associations of amide, imidazolidone, and dialkylurea groups, and the stoichiometry directly controls the mesoscopic structure and properties.

Synthesis of highly labile SG1-based alkoxyamines under photochemical conditions.

Highly labile SG1-based alkoxyamines were synthesized using the photodecomposition of both azo compounds and dithiocarbamates. The former method was a straightforward procedure to obtain the alkoxyamines, but a high [azo]/[nitroxide] ratio is needed. The latter method required only a stoichiometric amount of dithiocarbamate and allowed the recovery of the disulfide after irradiation. This enabled combination of the two methods in a process where only 0.75 equiv of azo compound is needed and where sulfurous compounds acted only as intermediates.

Alkoxyamine-mediated radical synthesis of indolinones and indolines.

Thermolysis of alpha-alkoxyamino propionanilides produces indolinones, whereas thermal reaction of N-allylaniline derivatives with various Tordo-type alkoxyamines results in formation of indolines in the radical regime. [reaction: see text]

Alkoxyamine-mediated radical cyclizations.

[reaction: see text] We present a new "conjunctive" radical cyclization process that involves the reaction of a 1,6-diene with the Tordo alkoxyamine, an agent originally developed for the radical polymerization of certain olefins through the "persistent radical effect".