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Currently most technologies available to produce esters require acid or base catalysts for esterification or transesterification reactions. Production of dimerate esters (DE) exhibiting potential as a biolubricant for low temperature applications using catalyst‐ and solvent‐free approaches is presented in this article. Hydrogenated C36 dimer acid and alcohol are reacted under the following conditions: dimer acid/alcohol (1:4.5 molar ratio), 150–200 °C, 24 h, 3Å molecular sieve (15% w/w). The performances of four DE species—dibutyl, dihexyl, di‐(2‐ethylhexyl), and dioctyl dimerate—as lubricant base stocks are evaluated by kinematic viscosity, viscosity index, cloud and pour point (cold flow properties) as well as oxidative stability, and compared with commercial synthetic lubricant base stock and DE, Radialube 7121. High viscosity indexes ranging between 129 and 138 are observed for the synthesized DEs, which are comparable with two commercial base stock, polyalpha olefin (PAO), and polyolester (POE). Significantly low pour point, less than −42 °C, is observed for di‐(2‐ethylhexyl) dimerate attributed to the branching of the side chain. The DEs are categorized as ISO VG 68 based on their viscosity according to ISO 3448 classification and show potential as biolubricant with high viscosity index and excellent cold flow properties. Practical Applications: DFAE obtained have high potential to be used as lubricant base stock for equipment and machinery operating at extremely low temperature.

Acetalization of glycerol with acetone (1 : 5) at 60 °C catalyzed by A‐46 (10 wt %) under nitrogen (N2) afforded 63 % solketal 1 a in just 15 min. Subsequently, acetalization of glycerol and bio‐based aldehydes i. e. acetaldehyde, isobutyraldehyde, n‐heptaldehyde, p‐anisaldehyde and benzaldehyde were investigated under optimized reaction conditions. The conversion and selectivity of this reaction was found to be affected by structure of aldehydes employed. Excellent conversion of 97 and 99 % were obtained using acetaldehyde and isobutyraldehyde, respectively while longer chain or aromatic aldehyde gave poor conversion between 17 and 36 %. Aldehyde with branching or aromatic ring gave better selectivity towards 6‐membered ring acetal b at the expense of conversion: p‐anisaldehyde > benzaldehyde>isobutyraldehyde>acetaldehyde>n‐heptaldehyde. Conversely, organic solvent gave adverse effects to both conversion and selectivity towards b. Optimized acetalization of glycerol/benzaldehyde was also studied. A‐46 has shown excellent stability and reactivity with no significant loss of catalytic activity in 10 subsequent runs.

The physico-chemical and electrical insulating properties of certain palm oil products, including triglyceride oils, fatty acids, fatty esters, and glycerol were evaluated for use in oil-immersed transformers. The studied triglyceride oils have excellent kinematic viscosity values: 30.25-40.49 mm 2 s À1 at 40 C, 6.46-8.34 mm 2 s À1 at 100 C; flash point: 278-320 C; moisture content: 16-175 mg kg À1 and dielectrical breakdown voltage: 29.1-40.9 kV. Fatty acids and fatty esters have relatively lower kinematic viscosity and flash point values than triglyceride oils. The type of hydrocarbon chain, hydrocarbon chain length and molecular size were shown to have substantial effects on the physico-chemical and electrical properties of the studied oils. The drying process imposed on refined-bleached-deodorized palm olein (RBD POo) has reduced the moisture from 400 mg kg À1 to 100 mg kg À1 and improved the dielectrical strength from 31.1 kV to 76.8 kV. Blending of RBD POo with fatty acids or fatty esters has improved the kinematic viscosity of RBD POo and offers even higher flash and fire points than mineral oil. This study showed that palm oil and palm oil products have strong potential to serve as coolants and may be safer for use in oil-filled transformers as compared to mineral oil.

Plant oil-based lubricants are used as alternative for mainstream petroleum-based lubricants mainly because they are known to be environmentally friendly. However, their market acceptance is limited by their high pour point and poor oxidation stability. This study presents an approach to make biodegradable lubricant from oleic acid that shows low pour point and satisfactory oxidation stability. A mixture of estolides with acetyl and hydroxy functionalities is prepared from reaction between oleic acid, acetic acid, and hydrogen peroxide. Subsequently, the hydroxy groups of estolide are end-capped with lauric acid to improve oxidation stability. Further reaction with alcohol and amine yielded estolide ester and amide, respectively. Physicochemical properties evaluation of prepared estolide ester and amide reveal that they have properties comparable to commercial samples in terms of pour point, oxidation stability, viscosity index, and antiwear. Furthermore, both estolide ester and amide are found to be readily biodegradable, which support their use as environmental friendly lubricant. Therefore, the inferior properties of plant oil-based lubricants can be resolved by chemical modifications that yield specific estolide ester and amide with excellent properties suitable for lubricants. Practical Applications: The prepared estolide ester and amide have good potential to be used as lubricant base oil for environmentally acceptable lubricants due to their inherent readily biodegradability nature and excellent lubricant properties.

SYNTHESIS OF DIMERATE ESTERS BY SOLVENT-FREE METHOD Journal of Oil Palm Research Vol. 29 (1) March 2017 p. 110 -119 INTRODUCTIONDimer acids are commonly derived from unsaturated fatty acids mainly consist of oleic and linoleic acids such as tall oil and high oleic tallow (Elsasser and McCargar, 2001). Some dimer acids are produced from erucic acid, a monounsaturated omega-9 fatty acid of rapeseed oil (Morway et al., 1954). Palm oil or so-called golden crop, that contains oleic acid as one of the major fatty acid (37.1%) as well as linoleic acid (8.1%) (Tan and Nehdi, 2012) can be used as a renewable feedstock for production of dimer acid. This dimer acid appeared as very viscous light yellow liquid and is widely used as raw material in the polymeric synthesis of fatty polyamides for application as resins (Mohammad et al., 2013) and hot melt adhesives (Ghasem, 2014). It is a useful polymer building block because they are able to impart the highly desirable properties of flexibility, elasticity and high impact strength to many polymer products. Besides polyamides, C 36 dimerate esters which commonly used as chain oils, 2T and 4T oils (Randles, 2006) can be derived by esterification of C 36 dimer acid and alcohol. Dimerate esters generally have good thermal and oxidant stability which make them an excellent lubricant. Furthermore, the stability can be improved by hydrogenation of the double bonds. This diester is commonly used in two-stroke, predominantly in marine application as it provides low smoke properties and good biodegradability for spilled or combusted oil. The degree of biodegradability of esters are generally higher than corresponding hydrocarbons (Buenemann et al., 2003). Several patents have been filed on the use of dimer esters for many non-polymer industrial chemicals such as synthetic lubricants (Henry and Tierney, 1962;Matuszak and Craven, 1958;Tierney, 1960) and lubricant additives (Rutkowski and Szykowski, 1976

Please cite this article as: Page PCB, Chan Y, Noor Armylisas AH, Alahmdi M, Asymmetric epoxidation of chromenes mediated by iminium salts: Synthesis of mollugin and (3S,4R)-trans-3,4-dihydroxy-3, 4-dihydromollugin, Tetrahedron (20164-dihydromollugin, Tetrahedron ( ), doi: 10.10164-dihydromollugin, Tetrahedron ( /j.tet.2016 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Asymmetric Epoxidation of Chromenes Mediated by Iminium Salts: Synthesis of Mollugin and (3S,4R)-trans-3,4-Dihydroxy-3,4-Dihydromollugin

Crude glycerol (CG) and glycerol pitch (GP) are highly alkaline residues from biodiesel and oleochemical plants, respectively, and have organic content which incurs high disposal cost and poses an environmental threat. Characterization of these residues for composition and properties could provide insight into their quality for proper disposal and can help the biodiesel industry to adopt more sustainable practices, such as reducing waste and improving the efficiency of the production process, hence minimizing the impact of the biodiesel supply chain to the environment. These data also allow the identification and exploration of new ways for their utilization and transformation into highly value-added products. In this study, we evaluated four CG samples (B, C, D, and E) and two GP samples (F and G) obtained from Malaysian palm oil refineries, and the results were compared with pure glycerol (A). Spectroscopic analysis was performed using FTIR, 1 H-, and 13 C-NMR. All samples had similar density to A (1.26 g/cm 3 ), except for F (1.31 g/cm 3 ), while the density for E and G could not be determined due to their physical states. The pH and viscosity largely varied in the range of 7.26–11.89 and 43–225 cSt, respectively. The glycerol content of CG (B, C, D, and E) was high and consistent (81.7–87.3%) whereas GP F and G had 71.5 and 63.9% glycerol content, respectively. Major contaminants in CG and GP were water and matter organic non-glycerol (MONG), respectively. The water, ash, soap, and salt content were considerably low, which varied from 3.4 to 14.1%, 3.9 to 13.0%, 0.1 to 5.7%, and 4.1 to 9.2% respectively. Thermal analysis of CG and GP exhibited four phases of decomposition attributed to the impurities compared to the single phase in A. All samples had calorific values lower than A (18.1 MJ/kg) between 9.0 and 17.7 MJ/kg. Based on the results, CG and GP have high glycerol content which reveals their potential to be used as feedstock in bioconversion and chemical or thermal treatment while impurities may be removed by pre-treatment if required. As palm oil is one of the main feedstocks for the oleochemical industry, this work underlines the importance of characterization of the residue generated to provide additional data and information on palm-based agricultural industry wastes, minimize the impact of palm oil supply chain on the environment, and explore its potential usage for value-addition. Supplementary Information The online version contains supplementary material available at 10.1007/s13399-023-04003-4.