Methanol-Based Esterification of Palm Oil Sludge – Preparation of Palmitic and Oleic Fatty Acid Ethyl Esters via Ethyl Acetate Transesterification

Acid-catalyzed Fischer esterification of fatty acids with methanol as a reagent and solvent is used to prepare long chain alkyl methyl esters. Transesterification of palm oil in basic media using methanol is a synthesis route to prepare monoalkyl methyl esters of fatty acids. In this work, we report performing Fischer esterification of a sample of local palm oil sludge (rich in fatty acids) in the presence of methanol and obtaining ethyl esters of oleic and palmitic acids from transesterification reactions during extractions with ethyl acetate.

Giving superabsorbent polymers a second life as pressure-sensitive adhesives

An estimated 6.3 billion metric tons of post-consumer polymer waste has been produced, with the majority (79%) in landfills or the environment. Recycling methods that utilize these waste polymers could attenuate their environmental impact. For many polymers, recycling via mechanical processes is not feasible and these materials are destined for landfills or incineration. One salient example is the superabsorbent material used in diapers and feminine hygiene products, which contain crosslinked sodium polyacrylates. Here we report an open-loop recycling method for these materials that involves (i) decrosslinking via hydrolysis, (ii) an optional chain-shortening via sonication, and (iii) functionalizing via Fischer esterification. The resulting materials exhibit low-to-medium storage and loss moduli, and as such, are applicable as general-purpose adhesives. A life cycle assessment demonstrates that the adhesives synthesized via this approach outcompete the same materials derived from petroleum feedstocks on nearly every metric, including carbon dioxide emissions and cumulative energy demand.

Propyl Gallate

The title compound, propyl gallate (III), is an important substance popularly used in the food, cosmetic and pharmaceutical industries. Current chemical syntheses of this compound are based on the acylation supported by thionyl chloride, DIC/DMAP or Fischer esterification using a range of homogenous and heterogenous catalysts. In this paper, an efficient, green, straightforward, and economical method for synthesizing propyl gallate using potassium hydrogen sulfate, KHSO4, as the heterogenous acidic catalyst has been developed for the first time. In addition, this paper provides a comprehensive spectral dataset for the title compound, especially the new data on DEPT and 2D NMR (HSQC and HMBC) spectra which are not currently available in the literature.

PTFE-Carbon Nanotubes and Lipase B from Candida antarctica—Long-Lasting Marriage for Ultra-Fast and Fully Selective Synthesis of Levulinate Esters

An effective method for levulinic acid esters synthesis by the enzymatic Fischer esterification of levulinic acid using a lipase B from Candida antarctica (CALB) immobilized on the advanced material consisting of multi-wall carbon nanotubes (MWCNTs) and a hydrophobic polymer—polytetrafluoroethylene (Teflon, PTFE)—as a heterogeneous biocatalyst, was developed. An active phase of the biocatalyst was obtained by immobilization via interfacial activation on the surface of the hybrid material MWCNTs/PTFE (immobilization yield: 6%, activity of CALB: 5000 U∙L∙kg−1, enzyme loading: 22.5 wt.%). The catalytic activity of the obtained biocatalyst and the effects of the selected reaction parameters, including the agitation speed, the amount of PTFE in the CALB/MWCNT-PTFE biocatalyst, the amount of CALB/MWCNT-PTFE, the type of organic solvent, n-butanol excess, were tested in the esterification of levulinic acid by n-butanol. The results showed that the use of a two-fold excess of levulinic acid to n-butanol, 22.5 wt.% of CALB on MWCNT-PTFE (0.10 wt.%) and cyclohexane as a solvent at 20 °C allowed one to obtain n-butyl levulinate with a high yield (99%) and selectivity (>99%) after 45 min. The catalyst retained its activity and stability after three cycles, and then started to lose activity until dropping to a 69% yield of ester in the sixth reaction run. The presented method has opened the new possibilities for environmentally friendly synthesis of levulinate esters.

Sustainable Esterification of a Soda Lignin with Phloretic Acid

In this work, a sustainable chemical process was developed through the Fischer esterification of Protobind® lignin, a wheat straw soda lignin, and phloretic acid, a naturally occurring phenolic acid. It aimed at increasing the reactivity of lignin by enhancing the number of unsubstituted phenolic groups via a green and solvent-free chemical pathway. The structural features of the technical and esterified lignins were characterized by complementary spectroscopic techniques, including 1H, 13C, 31P, and two-dimensional analysis. A substantial increase in p-hydroxyphenyl units was measured (+64%, corresponding to an increase of +1.3 mmol g−1). A full factorial design of the experiment was employed to quantify the impact of critical variables on the conversion yield. The subsequent statistical analysis suggested that the initial molar ratio between the two precursors was the factor predominating the yield of the reaction. Hansen solubility parameters of both the technical and esterified lignins were determined by solubility assays in multiple solvents, evidencing their high solubility in common organic solvents. The esterified lignin demonstrated a better thermal stability as the onset of thermal degradation shifted from 157 to 220 °C, concomitantly to the shift of the glass transition from 92 to 112 °C. In conclusion, the esterified lignin showed potential for being used as sustainable building blocks for composite and thermoset applications.

Synthesis and ‎characterization ‎of a new acid ‎molten salt and ‎the study of ‎its ‎thermal ‎behavior and ‎catalytic ‎activity ‎in Fischer ‎esterification ‎

A new acid molten salt was ‎‎prepared and its structure ‎‎elucidation was conducted ‎‎by FTIR, ‎‎1D NMR, 2D NMR, ‎‎and mass spectrometry. ‎Further support to ‎elucidate the chemical ‎structure of...

SYNTHESIS AND PRELIMINARY MOLECULAR DOCKING STUDIES OF NOVEL ETHYL-GLYCINATE AMIDE DERIVATIVES

Ethyl glycinate was synthesized by the Fischer esterification protocol, and its amide derivatives; 2-amino-N-(nitrophenyl)acetamide 31, 2-amino-N-(6-methylpyridin-2-yl) acetamide 33, N,N'-(1,4-phenylene)bis-(2-aminoacetamide) 35, N,N'-(6-chloropyrimidine-2,4-diyl)bis-(2-aminoacetamide) 37, and 2,4-(diamino-N’N-6-hydroxypyrimidyl)acetamide 39 respectively were obtained by coupling reactions of 4-nitroaniline, 2-amino-6-methylpyridine, 1,4-diamino-N,N’-benzene, 2,6-diamino-4-chloropyrimidine and 2,4-diamino-6-hydroxypyrimidine respectively with ethyl glycinate. These compounds were characterized on the basis of their melting points, UV-Visible, IR, 1HNMR and 13CNMR spectroscopic analyses. The results obtained from the spectra were consistence with the assigned structures of the compounds. The synthesized compounds were subjected to molecular docking with a target protein, 1CVU to compare their binding energies with celecoxib and rofecoxib which are standard drugs that inhibit COX2 enzyme. From the docking results, the binding energies values of the above synthesized compounds are -5.8 kJmol-1, -6.2 kJmol-1, -7.2 kJmol-1, -7.4 kJmol-1 and -7.6 kJmol-1 respectively. Compound 39 showed the highest binding energy of -7.6 kJmol-1, close to celecoxib and rofecoxib with binding energy values of -8.0 kJmol-1 and -8.2 kJmol-1 respectively. This result indicates that compound 39 possess some level of inhibitory activity against COX2.