R ESEARCH ARTICLEdoi: 10.2306/scienceasia1513-1874.2021.010

Green synthesis of alkyl 8-(2-butyl-5-octyl-1,3-dioxolan-4-yl)octanoate derivatives as potentialbiolubricants from used frying oilYehezkiel Steven Kurniawan, Kevin Thomas, Hendra, Jumina, Tutik Dwi Wahyuningsih∗

Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada,Yogyakarta 55281 Indonesia

∗Corresponding author, e-mail: tutikdw@ugm.ac.idReceived 10 Jan 2020Accepted 12 Dec 2020

ABSTRACT: Three pentanal-derived acetal esters have been prepared using a sonochemical method employingthe principles of green chemistry. As many as two steps were required to produce these esters of alkyl 9,10-dihydroxystearate in 67-85% yield. The green synthesis evaluation was carried out through a comparison betweenreflux and sonochemical methods, as well as homogeneous and solid acid catalysts. Activation of Indonesian naturalbentonite was conducted by Bronsted acid-enabled dealumination to obtain a low-cost solid acid catalyst. It was foundthat sonochemical esterification of the acid-catalyzed by H-bentonite gave products in up to 70% yield in 3 timesshorter reaction time than the reflux method, which is remarkable. The final acetalization step with n-pentanal in thepresence of H-bentonite with sonochemical method afforded three pentanal-derived dioxolane derivatives in 69–85%yields, which are higher than the conventional method. Examination of the physicochemical properties of each productrevealed that methyl 8-(2-butyl-5-octyl-1,3-dioxolan-4-yl)octanoate is the most suitable novel biolubricant to substitutecurrently commercial lubricant.

KEYWORDS: biolubricant, used frying oil, green synthesis, activated bentonite, sonochemical method

INTRODUCTION

As annual world energy consumption rises everyyear, the utilization of renewable raw materials asthe energy source will undoubtedly play an im-portant role in the near future [1–3]. Amongavailable alternatives, vegetable oils are the mostconsumed materials [4, 5]. Specifically, researchconcludes that vegetable oils have the potential tosubstitute currently used lubricant composed solelyof hydrocarbons. This is because vegetable oils areabundantly available, biodegradable, and have lowtoxicity [6, 7]. However, due to the unsaturationbonds are present, they exhibit low thermal andoxidative stability [8]. Structural modification ofthe vegetable oils is thus needed to overcome theseproblems, while at the same time maintaining theirability as biolubricant [9–12].

Efforts on biolubricant formulation from veg-etable oils have been carried out to find the best bi-olubricant candidate [13–20]. Epoxidation of oleicacid and followed by a ring-opening reaction gaveether-based biolubricant; however, the biolubricantgave low viscosity index, which is unfavorable [13].On the other hand, hydroxylation and acylation of

oleic acid gave triester-based biolubricant; however,the total acid numbers were too high to be em-ployed in a real application [14]. As part of ourcontribution to finding a substitute for conventionallubricant, we reported in our previous work that theketal-derived ethyl 9,10-dihydroxystearate showedconsiderably good physicochemical properties, i.e.lower total acid number (TAN) value and iodinevalue (IV) than commercial lubricant [15, 16]. Fur-thermore, the density of the esters is in the rangeof what is required to be a good lubricant. How-ever, their total base number (TBN) value is stillhigh (14.0 mg KOH/g), which, in turn, indicatesthat further improvement is needed to obtain idealbiolubricant. Meanwhile, the aromatic aldehydederivatives gave solid products, thus, the productscould not be used as biolubricant [17].

On the other hand, green synthesis process ofbiolubricant has been also considered for a betterfuture and environmental sustainability [21–24].Anastas and Eghbali introduced the principles ofgreen chemistry, some of which are the designof energy-efficient synthetic method, employ het-erogeneous catalyst, conduction of less hazardous

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2 ScienceAsia 47 (2021)

chemical syntheses, and use of safer chemicals andsolvents [25]. One alternative to replacing refluxas a synthetic method is sonochemical synthesisas it utilizes sound waves rather than requiringheat for the reaction [26]. Heterogeneous catalystsare generally favored over homogenous catalysts interms of a simple and green process [27].

Indonesia, specifically Tasikmalaya, is rich innatural clays. One of the most commonly foundnatural clays is bentonite. So far, bentonites havefound variable uses such as acid catalyst [21], ion-exchange agent [28], heavy metals adsorbent [29],and slow-release agent [30] in the industrial con-version of crude oil [31], owing to their porosity andacidity. Additionally, bentonite is able to act as a het-erogeneous catalyst in esterification and then recov-ered after the reaction process [32]. To overcome allthe aforementioned problems, in the present work,we reported the green synthesis of pentanal-deriveddioxolane compounds and the evaluation of theirpotential application as biolubricants. Pentanalwas selected because it is commercially availableto be used as a raw material in the rubber andresin industries. The aspects of green chemistrymet in this experiment were the use of the greensynthesis method (sonochemistry), the avoidanceof hazardous reagent (sulfuric acid), and the em-ployment of heterogenous catalysis (activated ben-tonite). Furthermore, the physicochemical proper-ties of the synthesized compounds were tested incomparison to the commercial lubricants.

MATERIALS AND METHODS

Materials

Used frying oil was obtained from a traditionalmarket in Yogyakarta, Indonesia; while naturalbentonite was obtained from Tasikmalaya, In-donesia. The other chemicals, such as sulfuricacid, methanol, ethanol, n-propanol, isopropanol,dichloromethane, pentanal, sodium hydroxide,potassium permanganate, anhydrous sodium sul-fate, sodium bicarbonate, and p-toluenesulfonicacid (p-TSA) were purchased from Merck in proanalytical grade and used without any further pu-rification.

Activation of natural bentonite

Activation of natural bentonite was carried outthrough an acidic activation in a similar manner tothe previously described procedure [33]. Briefly,natural bentonite (250 g) was grounded and filteredto 100 mesh. Then 1.0 M sulfuric acid in distilled

water was poured into the material and the mixturewas heated at 350 K for 3 h. The residue was filteredand washed with distilled water until the filtrate wasfree from sulfate ions. The residue was dried andfiltered to 100 mesh to obtain activated bentonite(abbreviated as H-bentonite). Natural bentoniteand H-bentonite were characterized by FTIR, XRD,surface analysis, and SEM-EDX.

Esterification of used frying oil

In the present work, used frying oil was utilized asthe fatty acid source. Briefly, the mixture betweenused frying oil (20 g) and 20% wt/vol sodiumhydroxide in methanol (50 ml) was refluxed for 1 h.Afterward, n-hexane (3×20 ml) was added into themixture for extracting the fatty acid methyl estersas the product. The organic phase was dried overanhydrous sodium sulfate and, then, the solvent wasremoved under vacuum. The obtained fatty acidmethyl esters were characterized by FT-IR (FourierTransform Infrared, Shimadzu Prestige 21) and GC-MS (Gas Chromatography-Mass Spectrometry, Shi-madzu QP 2010S with Agilent GC Type 6890-MSType 5973) spectrometry. See supplementary datafor the characterization of the products.

Hydrolysis of fatty acid methyl esters

The mixture of fatty acid methyl esters (5.0 g) wasadded into 2% wt/vol KOH in methanol (30 ml);and the mixture was refluxed for 2 h. After that, themixture was acidified with 1 M hydrochloric aciduntil a pH of 1.0 was reached. Then, petroleumether (5×10 ml) was added to the mixture, theorganic phase was dried over anhydrous sodiumsulfate, and the solvent was removed under vacuum.The obtained fatty acids were characterized by FT-IRspectrometry.

Esterification of 9,10-dihydroxyoctadecanoicacid

The 9,10-dihydroxyoctadecanoic acid was preparedusing potassium permanganate as the oxidationagent under an alkaline condition as previouslydescribed [16]. The 9,10-dihydroxyoctadecanoicacid (0.316 g, 1 mmol) was dissolved in 100 mmolof alcohol (methanol, ethanol, n-propanol, and iso-propanol separately). Then acid catalyst (2 ml ofconcentrated sulfuric acid or 50 mg of heterogenouscatalyst) was added to the mixture. The mixturewas refluxed as a representative of the conven-tional method or sonicated for 10–30 min. Afterthe reaction had been completed, the catalyst wasfiltered off. Distilled water (10 ml) was added to the

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filtrate. The precipitated product was filtered andrecrystallized with acetonitrile to obtain the desiredproduct.

Acetalyzation of alkyl9,10-dihydroxyoctadecanoate

The alkyl 9,10-dihydroxyoctadecanoate ester(2 mmol) and n-pentanal (0.2 g, 2 mmol) weredissolved in dichloromethane (25 ml). Then, acidcatalyst (50 mg of p-TSA or 50 mg of heterogenouscatalyst) was added to the mixture. The mixturewas refluxed as a representative of the conventionalmethod or sonicated for 30 min. After the reaction,the mixture was filtered. Then, the organic phasewas washed with brine (10 ml) three times and3.0% w/t sodium bicarbonate solution (10 ml)twice. The organic phase was dried over anhydroussodium sulfate and the solvent was removed undervacuum to obtain the desired product.

Biolubricant test of alkyl 8-(2-butyl-5-octyl-1,3-dioxolan-4-yl)octanoates

The density of the synthesized products was deter-mined by a 10.0 ml pycnometer according to theAmerican Society for Testing and Material (ASTM)D1481 standard method. The dynamic viscosityand viscosity index of the synthesized productswere measured by Ostwald viscometer according toASTM D445 and D2770 methods.

The total acid number (TAN) of the synthesizedproducts was determined by alkalimetric titrationaccording to ASTM D964 standard method; whilethe total base number (TBN) of the synthesizedproducts was determined by acidimetric titrationaccording to ASTM D974 standard method. Theiodine value (IV) of the synthesized products wasdetermined by iodometric titration according toASTM D2078 standard method. Each measurementwas carried out in three replications and the averagevalues from the measurement data were used.

RESULTS AND DISCUSSION

Catalyst activation

Characterization of H-bentonite using FT-IR spec-troscopy (Fig. 1(A)) reveals that activation of ben-tonite has been successfully carried out. After theactivation process, the O−Si−O stretching peak at787 cm−1 is sharpened and the TO4 (T = Si orAl) absorption peak becomes wider in the range of1203–979 cm−1. These prove that the dealumina-tion process by acid treatment of the parent natural

787918

1087-1010

162534383650

787

1203-979

1625

34423652

5001000150020002500300035004000

Transmittance(%)

Wavenumber (cm-1)

(A)

(a)

(b)

Inte

nsity

(arb

. u.)

d001(B)

(b)

(a)

Diffraction angle 2 θ (degree)

Fig. 1 (A) FTIR spectra and (B) XRD diffractogram of(a) bentonite and (b) H-bentonite.

bentonite is achieved since the Si/Al ratio was de-creased as previously described [29–31]. Further-more, the O−H absorption peaks of silanol groupsin 3400–3650 cm−1 were shifted towards largerwavenumbers as the cationic impurities coordinatedto the water in the pore of zeolite is eluted duringthe activation process [29]. The success of bentoniteactivation can also be elucidated by the reducedAl−O−Al bending absorption intensity at 918 cm−1as most of aluminum in the clay is dissolved in theacid. The XRD spectrum (Fig. 1(B)) shows thatthe d001 peak of bentonite structure was shiftedto a lower 2θ value (from 6.790 to 5.279) with ahigher peak intensity confirming successful removalof impurities from bentonite structure; thus, thed001 was increased from 13.0076 to 16.7269 nm.This result is in agreement with the previous lit-erature [33]. The SEM images of both catalystmaterials were shown in Fig. 2. After the activationprocess, the particles were well-distributed. Fur-thermore, from the gas adsorption isotherm anal-ysis, the pore characters of natural bentonite andH-bentonite materials were listed in Table 1. Itwas found that the surface area of the H-bentonite(133.5 m2/g) is 1.7 times higher than that of thenatural bentonite (76.87 m2/g). Furthermore, the

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(a)

(b)

Fig. 2 SEM: (a) bentonite and (b) H-bentonite.

Table 1 Pore characters of natural bentonite and H-bentonite materials.

Surface Pore Pore Bronsted LewisMaterial area volume size acid site site

(m2/g) (cm3/g) (nm) (mmol/g) (mmol/g)

Natural 76.87 17.7 8.40 2.89 3.29bentoniteH-bentonite 133.50 30.7 8.89 8.66 4.08

Bronsted acid sites were determined from the vaporadsorption of ammonia and pyridine on the surfaceof the catalyst material [34]. The Bronsted acid siteon the H-bentonite is 8.66 mmol/g, which is higherthan that of the natural bentonite (2.89 mmol/g).Meanwhile, the Lewis acid site on the H-bentoniteis 4.08 mmol/g, which is higher than that of thenatural bentonite (3.29 mmol/g). The increment ofthe Bronsted and Lewis acid sites would contributeto a higher catalytic activity of H-bentonite for theorganic reaction [33]. The pore volume and poresize of the H-bentonite (Table 1) were also largerconfirming that the activation process has been suc-cessfully carried out.

Esterification of used frying oil and hydrolysisof fatty acid methyl esters

The synthesis scheme of alkyl 8-(2-butyl-5-octyl-1,3-dioxolan-4-yl)octanoate derivatives from usedfrying oil is shown in Fig. 3. The successful ester-ification reaction of used frying oil was shown fromthe appearance of C−−O and C−O ester bonds at1743 and 1180 cm−1, respectively. These functionalgroups are characteristics for the production of fattyacid methyl ester [17, 18]. From the GC-MS analysisthrough methylation of fatty acids, it was found thatthe used frying oil contains 1.20% myristic acid,36.99% palmitic acid, 12.03% linoleic acid, 41.73%oleic acid, and 5.73% stearic acid. Meanwhile, theaccomplishment hydrolysis reaction of the fatty acidmethyl esters was shown from the shifting of C−−Osignal from 1743 to 1712 cm−1 together with theappearance of O−H signal at 3394 cm−1. Thesespectral changes are characteristics for the produc-tion of free fatty acid [17]. Afterward, the fattyacids were oxidized using potassium permanganateunder alkaline conditions. From the mixture offatty acids, only oleic acid could be reacted to form9,10-dihydroxystearic acid; while the other fattyacids were eliminated through a recrystallizationprocess [18]. The 9,10-dihydroxystearic acid wasobtained in a 45.17% yield.

Green esterification of 9,10-dihydroxystearicacid

The obtained 9,10-dihydroxystearic acid was ester-ified with various types of alcohol, i.e. methanol,ethanol, n-propanol, and isopropanol, in the pres-ence of an acidic catalyst (concentrated sulfuric acidor natural bentonite or H-bentonite). The synthesisexperiment was begun by comparing the esteri-fication result between conventional, i.e. reflux(Table 2, entries 1, 5, 9, and 13), and sonochemicalmethod (Table 2, entries 2, 6, 10, and 14). Bothmethods were conducted in the presence of concen-trated sulfuric acid. The reflux method required alonger reaction time than the sonochemical method,and remarkable yield of each ester was obtainedusing the sonochemical method. However, muchlower yield for sonochemical method was resulted,when ethanol, n-propanol, and isopropanol wereused. It is reasonable since the reaction time ofthe reflux method was longer than the sonochem-ical method [26]. Despite this, the calculatedenergy needed to drive the sonochemical reaction(257 kW) was tremendously lower than the con-ventional method (16 000 kW). Moreover, the time

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Fig. 3 Synthesis scheme of alkyl 8-(2-butyl-5-octyl-1,3-dioxolan-4-yl)octanoate derivatives from used frying oil.

Table 2 Catalysis and method variation of the ester ofalkyl 9,10-dihydroxystearate synthesis.

Entry R′ Catalyst Reaction Yieldtime (min) (%)

1 −CH3 H2SO4 30 882 −CH3 H2SO4 10 723 −CH3 Bentonite 10 674 −CH3 H-bentonite 10 735 −CH2CH3 H2SO4 30 816 −CH2CH3 H2SO4 10 607 −CH2CH3 Bentonite 10 598 −CH2CH3 H-bentonite 10 749 −CH2CH2CH3 H2SO4 30 6410 −CH2CH2CH3 H2SO4 10 4411 −CH2CH2CH3 Bentonite 10 2212 −CH2CH2CH3 H-bentonite 10 3013 −CH(CH3)2 H2SO4 30 4714 −CH(CH3)2 H2SO4 10 2215 −CH(CH3)2 Bentonite 10 516 −CH(CH3)2 H-bentonite 10 7

of reaction for sonochemical method (10 min) wasthree times shorter than the reflux one (30 min).Therefore, the product yield can be compensated bythese facts.

With the decision that sonochemical method

was reasonable to use, then, the synthesis processwas moved on to analyze the performance of eachheterogeneous catalyst on this sonochemical ester-ification reaction. Overall, under the same massand reaction time, H-bentonite catalyzed the reac-tion more efficiently compared to natural bentonite(Table 2). This finding is in agreement with thereported literatures [31–33]. This higher catalyticactivity of H-bentonite compared to natural ben-tonite is probably due to the higher number ofacid site, larger surface area, larger pore volume,and larger pore size in H-bentonite (Table 1) sothat 9,10-dihydroxystearic acid molecules are moreefficiently bound to the active sites of the catalysts.Furthermore, the uniformity of H-bentonite aggre-gates is higher than its unmodified counterpart,as can be seen by the SEM image (Fig. 2). Theyield of H-bentonite catalyzed esterifications arecomparable to the conventionally obtained yield formethyl and ethyl esters using concentrated sulfuricacid. Thus, the protocol for green practical methyland ester esterification of 9,10-dihydroxystearatewas successfully established using a sonochemicalmethod with H-bentonite catalyst, while the prepa-ration of the propyl and isopropyl esters will remaina challenge in the future.

Green synthesis of pentanal-derived dioxolanes

Attempts to synthesize pentanal-derived dioxolaneswere done by acetalization of methyl, ethyl, propyl,and isopropyl 9,10-dihydroxystearate. Firstly, wecompared the acetalization product of methyl 9,10-dihydroxystearate obtained between conventional

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Table 3 Effect of different catalysts on the yield ofpentanal-derived dioxolanes.

CO2RO

O

CO2RHO

HO

n-pentanal

catalystsonication

Entry R Catalyst Reaction Yieldtime (min) (%)

1 −CH3 p-TSA 30 742 −CH3 Bentonite 30 683 −CH3 H-bentonite 30 854 −CH2CH3 p-TSA 30 675 −CH2CH3 Bentonite 30 596 −CH2CH3 H-bentonite 30 787 −CH2CH2CH3 H-bentonite 30 698 −CH(CH3)2 H-bentonite 30 0

(catalyzed by p-TSA) and greener method (cat-alyzed by natural bentonite or H-bentonite) to de-termine the better catalyst among the three of them(Table 3, entries 1–3). Unsurprisingly, the reactioncatalyzed by H-bentonite gave the highest productyield compared to those catalyzed by p-TSA andnatural bentonite. The same trend was observedfor the synthesis using ethyl 9,10-dihydroxystearateas a substrate (Table 3, entries 4–6). This resultindicated that the catalytic activity of H-bentoniteas heterogeneous catalyst surpasses that of p-TSAas conventional homogeneous one, which fulfillsthe green chemistry principle [25]. One way toexplain this finding is that p-TSA has a higher Bron-sted acidic character than H-bentonite. Becauseacetalization is a reversible reaction, this ability ofp-TSA has a major drawback as some of the p-TSAmight hydrolyze the acetal back to the reactants.The calculated e-factor of using H-bentonite, i.e3.91, is lower than using p-TSA, i.e 4.83. Lowere-factor describes that the procedure gives a loweramount of waste [25]. This is due to the factthat H-bentonite can be filtered out of the productmixture and further reused as a recycled catalyst.The parameter of yield and e-factor concluded thatthe sonochemical acetalization conducted in thepresence of H-bentonite as catalyst was found as agreener method.

With this conclusion, propyl and isopropyl9,10-dihydroxystearate were then subjected to thesame sonochemical H-bentonite-catalyzed acetal-ization (Table 3, entries 7 and 8). The prod-uct obtained from n-propyl 9,10-dihydroxystearatewas in gel form, which was, therefore, not suit-able to be applied as lubricant. Meanwhile, theacetal was hardly obtained from isopropyl 9,10-

dihydroxystrearate due to steric hindrance. There-fore, the biolubricant evaluation was conductedonly for methyl, ethyl, and n-propyl pentanal-derived dioxolane compounds.

Physicochemical properties of pentanal-deriveddioxolanes

Based on ASTM as the standard method [18], somephysicochemical properties, such as density, viscos-ity, viscosity index, TAN, TBN, and IV, were de-termined for synthesized dioxolane compounds asgrease and oleic acid as starting material. The re-sults are presented in Table 4. A better lubricant hasa low density to allow less mechanical work requiredby the machines [1]. Of all the products obtain, onlymethyl ester dioxolane has the density which is inthe range of that required to be a good lubricant,i.e. 0.70–0.95 g/ml. Even though the methylester is denser than the commercial lubricant, bothmethyl and ethyl esters synthesized have a lowerdensity than oleic acid. In these esters, only van derWaals forces present, while there are van der Waalsand hydrogen bonding occurring intramolecularlyin oleic acid [18]. The viscosities and viscosityindexes of methyl ester obtained are comparable tocommercial lubricant. The high viscosity of lubri-cants is desired as it will prevent friction amongmetal parts in the machine [5].

The degree of engine corrosion due to the useof grease can be expressed as TAN [7]. As the acidfunctional group is converted into the correspond-ing esters, the resulting synthesized products havemuch a lower TAN value than oleic acid. The lowerTAN value of methyl and ethyl esters means thatthe utilization of these compounds will result inlower probability of engine corrosion compared tothat of commercial lubricants. On the other hand,TBN values can be used to interpret the ability oflubricants to neutralize the acids that might comefrom fuel combustion processes and prevent dirtfrom sticking on the engine component [1]. Thehigher value of TBN reveals the higher detergencyability of a compound. However, too high TBNvalue of a compound would make it not suitable as alubricant, as the presence of base tends to hydrolyzeester back to the acids. From the result presentedin Table 4, pentanal-derived dioxolane from methylester compensates both of these effects. In fact, itsTBN is slightly higher than commercial lubricant butlower than our previously reported TBN for ketalderived dioxolane (14.0 mg KOH/g). Lubricants aresometimes exposed to air and, consequently, thosethat have many double bonds or unsaturated groups

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Table 4 Physicochemical properties of pentanal-derived dioxolanes.

CO2RO

O

Compound Density Viscosity Viscosity TAN TBN IV(g/ml) (mPa s)a index (mg KOH/g) (mg KOH/g) (mg I2/g)

R = −CH3 0.926 162 108 59.9 8.26 0.13R = −CH2CH3 0.977 59.8 105 38.2 16.8 0.58R = −CH2CH2CH3 – – – 18.1 27.5 0.84Oleic acid 0.985 29.0 152 196 0.54 89.9Commercial lubricant 0.882 138 115 85.4 5.36 31.7

a Dynamic viscosity at 313 K.

could be oxidized [11]. The oxidative stabilityof a lubricant can be determined by a parametercalled iodine value (IV). Dihydroxylation followedby acetalization of the alkene functional groupsyields C−O σ bonds which are more stable thanthe π bonds. This explains the lower IV of theester products compared to oleic acid. Fortunately,these values are also lower compared to those in thecommercial lubricant, with methyl esters having thebest attribute as the potential biolubricant candidatefor a real application.

CONCLUSION

The green synthesis of pentanal-derived alkyl es-ter dioxolanes has been performed in two-step se-quence from 9,10-dihydroxystearic acid which is inturn obtained from used frying oil. Esterification ofthe acid by sonochemical method in the presenceof H-bentonite gave alkyl 9,10-dihydroxystearatesin reasonable yield and in a shorter reaction timethan conventional method. Then, H-bentonite-catalyzed sonochemical acetalization of the esterswith n-pentanal afforded methyl, ethyl, and n-propyl ester dioxolanes in higher yields than theobsolete method. Evaluation of phase, density,viscosity, TAN, TBN, and IV of each product re-veals that methyl 8-(2-butyl-5-octyl-1,3-dioxolan-4-yl)octanoate is the most suitable novel candidateas a biolubricant. These findings are hopefullyexpected to find application in the mechanical in-dustry as means of contribution towards achievingenvironmentally benign processes.

Appendix A. Supplementary data

Supplementary data associated with this articlecan be found at https://drive.google.com/file/d/1SRcUlS8v1UK5SF2HdWFPE3VwxsuNYuPS/view?usp=sharing

Acknowledgements: The authors thank the Ministry ofResearch Technology and Higher Education (Kemenris-tekdikti) of the Republic of Indonesia Indonesia for finan-cial support.

REFERENCES

1. Reeves CJ, Siddaiah A, Menezes PL (2017) A reviewon the science and technology of natural and syn-thetic biolubricants. J Bio Tribo Corros 3, 1–27.

2. Qian S-H, Hong L, Xu M, Cai Y-P, Lin Y, Gao J-S (2015)Cellulose synthesis in coloured cotton. ScienceAsia41, 180–186.

3. Buasri A, Chaiyut N, Loryuenyong V, Rodklum C,Chaikwan T, Kumphan N, Jadee K, Klinklom P, et al(2012) Transesterification of waste frying oil forsynthesizing biodiesel by KOH supported on coconutshell activated carbon in packed bed reactor. Sci-enceAsia 38, 283–288.

4. Soufi MD, Ghobadian B, Atashgaran M, Mousavi SM,Najafi G (2019) Biolubricant production from edibleand novel indigenous vegetable oils: mainstreammethodology and prospects and challenges in Iran.Biofuel Bioprod Bior 13, 838–849.

5. Singh Y, Sharma A, Singla A (2019) Non-edible veg-etable oil-based feedstocks capable of bio-lubricantproduction for automotive sector applications – Areview. Environ Sci Pollut Res 26, 14867–14882.

6. Salimon J, Salih N, Yousif E (2010) Biolubricants:Raw materials, chemical modifications and envi-ronmental benefits. Eur J Lipid Sci Technol 112,519–530.

7. Carlsson AS (2009) Plant oils as feedstock alterna-tives to petroleum – A short survey of potential oilcrop platforms. Biochimie 91, 665–670.

8. Jelani NAA, Azlan A, Ismail A, Khoo HE, Alinafiah SM(2017) Fatty acid profiles and antioxidant propertiesof dabai oil. ScienceAsia 43, 347–353.

9. Kananam W, Suksaroj TT, Suksaroj C (2011) Bio-chemical changes during oil palm (Elais guineen-sis) empty fruit bunches composting with decantersludge and chicken manure. ScienceAsia 37, 17–23.

www.scienceasia.org

http://www.scienceasia.org/https://drive.google.com/file/d/1SRcUlS8v1UK5SF2HdWFPE3VwxsuNYuPS/view?usp=sharinghttps://drive.google.com/file/d/1SRcUlS8v1UK5SF2HdWFPE3VwxsuNYuPS/view?usp=sharinghttps://drive.google.com/file/d/1SRcUlS8v1UK5SF2HdWFPE3VwxsuNYuPS/view?usp=sharinghttp://dx.doi.org/10.1007/s40735-016-0069-5http://dx.doi.org/10.1007/s40735-016-0069-5http://dx.doi.org/10.1007/s40735-016-0069-5http://dx.doi.org/10.2306/scienceasia1513-1874.2015.41.180http://dx.doi.org/10.2306/scienceasia1513-1874.2015.41.180http://dx.doi.org/10.2306/scienceasia1513-1874.2015.41.180http://dx.doi.org/10.2306/scienceasia1513-1874.2012.38.283http://dx.doi.org/10.2306/scienceasia1513-1874.2012.38.283http://dx.doi.org/10.2306/scienceasia1513-1874.2012.38.283http://dx.doi.org/10.2306/scienceasia1513-1874.2012.38.283http://dx.doi.org/10.2306/scienceasia1513-1874.2012.38.283http://dx.doi.org/10.2306/scienceasia1513-1874.2012.38.283http://dx.doi.org/10.1002/bbb.1953http://dx.doi.org/10.1002/bbb.1953http://dx.doi.org/10.1002/bbb.1953http://dx.doi.org/10.1002/bbb.1953http://dx.doi.org/10.1002/bbb.1953http://dx.doi.org/10.1007/s11356-019-05000-9http://dx.doi.org/10.1007/s11356-019-05000-9http://dx.doi.org/10.1007/s11356-019-05000-9http://dx.doi.org/10.1007/s11356-019-05000-9http://dx.doi.org/10.1002/ejlt.200900205http://dx.doi.org/10.1002/ejlt.200900205http://dx.doi.org/10.1002/ejlt.200900205http://dx.doi.org/10.1002/ejlt.200900205http://dx.doi.org/10.1016/j.biochi.2009.03.021http://dx.doi.org/10.1016/j.biochi.2009.03.021http://dx.doi.org/10.1016/j.biochi.2009.03.021http://dx.doi.org/10.2306/scienceasia1513-1874.2017.43.347http://dx.doi.org/10.2306/scienceasia1513-1874.2017.43.347http://dx.doi.org/10.2306/scienceasia1513-1874.2017.43.347http://dx.doi.org/10.2306/scienceasia1513-1874.2011.37.017http://dx.doi.org/10.2306/scienceasia1513-1874.2011.37.017http://dx.doi.org/10.2306/scienceasia1513-1874.2011.37.017http://dx.doi.org/10.2306/scienceasia1513-1874.2011.37.017www.scienceasia.org

8 ScienceAsia 47 (2021)

10. Phalakornkule C, Mangmeemak J, Intrachod K, Nun-takumjorn B (2010) Pretreatment of palm oil milleffluent by electrocoagulation and coagulation. Sci-enceAsia 36, 142–149.

11. Erhan SZ, Sharma BK, Peres JM (2006) Oxidationand low-temperature stability of vegetable oil-basedlubricants. Ind Crops Prod 24, 292–299.

12. Talkit KM, Mahajan DT, Massand VH (2012) Physic-ochemical properties of soybean oil and their blendswith vegetable oils for the evaluation of lubricantproperties. J Chem Biol Phys Sci 3, 490–497.

13. Madankar CS, Dalai AK, Naik SN (2013) Green syn-thesis of biolubricant base stock from canola oil. IndCrops Prod 44, 139–144.

14. Sammaiah A, Padmaja KV, Prasad RBN (2014) Syn-thesis and evaluation of novel acyl derivates fromjatropha oil as potential lubricant base stocks. J AgricFood Chem 62, 4652–4660.

15. Wahyuningsih TD, Kurniawan YS, Amalia S, Ward-hani TAK, Muriningsih CES (2019) Diethanolamidederivatives as a potential enhanced oil and used fry-ing oil: Isolation, synthesis, and evaluation as non-ionic biosurfactants. Rasayan J Chem 12, 741–748.

16. Kurniawan YS, Anwar M, Wahyuningsih TD (2017)New lubricant from used cooking oil: cyclic ketal ofethyl 9,10-dihydroxyoctadecanoate. Mater Sci Forum901, 135–141.

17. Wahyuningsih TD, Kurniawan YS (2017) Green syn-thesis of some novel dioxolane compounds fromIndonesian essential oils as potential biogrease. AIPConf Proc 1823, ID 020081.

18. Kurniawan YS, Ramanda Y, Thomas K, Hen-dra, Wahyuningsih TD (2017) Synthesis of 1,4-dioxaspiro[4.4] and 1,4-dioxaspiro[4.5] novel com-pounds from oleic acid as potential biolubricant.Indones J Chem 17, 301–308.

19. Wahyuningsih TD, Kurniawan YS (2020) Synthesisof dioxo-dioxane and dioxo-dioxepane ethyl oleatederivatives as bio-lubricant base stocks. Indones JChem 20, 504–509.

20. Wahyuningsih TD, Kurniawan YS, Musphianti N,Ceristrisani N, Suryanti AD (2020) Evaluation ofethanolamide based nonionic biosurfactant materialsfrom chemically modified castor oil and used palm oilwaste. Indian J Chem Tech 27, 326–332.

21. Hossain MA, Iqbal MAM, Julkapli NM, Kong PS,Ching JJ, Lee HV (2018) Development of catalystcomplexes for upgrading biomass into ester-basedbiolubricants for automotive applications: A review.RSC Adv 8, 5559–5577.

22. Owuna FJ, Dabai MU, Sokoto MA, Dangoggo SM,

Bagudo BU, Birnin-Yauri UA, Hassan LG, Sada I, et al(2020) Chemical modification of vegetable oils forthe production of biolubricants using trimethylol-propane: A review. Egyptian J Pet 29, 75–82.

23. Syahrullail S, Kamitani S, Shakirin A (2013) Per-formance of vegetable oil as lubricant in extremepressure condition. Procedia Eng 68, 172–177.

24. Bande YM, Adam NM, Jamarei BO, Azmi Y, RazaliSZ (2013) Examining the physicochemical propertiesand engine performance of biodiesel from wholeseed and extracted kernels of egusi (Citrullus lana-tus). ScienceAsia 39, 492–499.

25. Anastas P, Eghbali N (2010) Green chemistry: Princi-ples and practice. Chem Soc Rev 39, 310–312.

26. Wood RJ, Lee J, Bussemaker J (2017) A parametricreview of sonochemistry: Control and augmentationof sonochemical activity in aqueous solutions. Ultra-son Sonochem 38, 351–370.

27. Zhao X, Wei L, Cheng S, Julson J (2017) Review ofheterogeneous catalysts for catalytically upgradingvegetable oils into hydrocarbon biofuels. Catalysts 7,ID 83.

28. Karnland O, Birgersson M, Hedström M (2011)Selectivity coefficient for Ca/Na ion exchange inhighly compacted bentonite. Phys Chem Earth 36,1554–1558.

29. Liu X, Hicher P, Muresan B, Saiyouri N, Hicher P(2016) Heavy metal retention properties of kaolinand bentonite in a wide range of concentration anddifferent pH conditions. Appl Clay Sci 119, 365–374.

30. He Y, Wu Z, Tu L, Han Y, Zhang G, Li C (2015Encapsulation and characterization of slow-releasemicrobial fertilizer from the composites of bentoniteand alginate. Appl Clay Sci 109–110, 68–75.

31. Jiang Y, Li X, Qin Z, Ji H (2016) Preparation ofNi/bentonite catalyst and its applications in the cat-alytic hydrogenation of nitrobenzene to aniline. ChinJ Chem Eng 24, 1195–1200.

32. Moraes DS, Angélica RS, Costa CEF, Filho GNR,Zamian JR (2011) Applied clay science bentonitefunctionalized with propyl sulfonic acid groups usedas catalyst in esterification reactions. Appl Clay Sci51, 209–213.

33. Wijaya K, Ariyanti AD, Tahir I, Syoufian A, Rach-mat A, Hasanudin (2018) Synthesis of Cr/Al2O3-bentonite nanocomposite as the hydrocracking cat-alyst of castor oil. Nano Hybrid Compos 19, 46–54.

34. Utami M, Wijaya K, Trisunaryanti W (2018) Pt-promoted sulfated zirconia as catalyst for hydroc-racking of LDPE plastic waste into liquid fuels. MaterChem Phys 213, 548–555.

www.scienceasia.org

http://www.scienceasia.org/http://dx.doi.org/10.2306/scienceasia1513-1874.2010.36.142http://dx.doi.org/10.2306/scienceasia1513-1874.2010.36.142http://dx.doi.org/10.2306/scienceasia1513-1874.2010.36.142http://dx.doi.org/10.2306/scienceasia1513-1874.2010.36.142http://dx.doi.org/10.1016/j.indcrop.2006.06.008http://dx.doi.org/10.1016/j.indcrop.2006.06.008http://dx.doi.org/10.1016/j.indcrop.2006.06.008http://dx.doi.org/10.1016/j.indcrop.2012.11.012http://dx.doi.org/10.1016/j.indcrop.2012.11.012http://dx.doi.org/10.1016/j.indcrop.2012.11.012http://dx.doi.org/10.1021/jf501388dhttp://dx.doi.org/10.1021/jf501388dhttp://dx.doi.org/10.1021/jf501388dhttp://dx.doi.org/10.1021/jf501388dhttp://dx.doi.org/10.31788/RJC.2019.1225140http://dx.doi.org/10.31788/RJC.2019.1225140http://dx.doi.org/10.31788/RJC.2019.1225140http://dx.doi.org/10.31788/RJC.2019.1225140http://dx.doi.org/10.31788/RJC.2019.1225140http://dx.doi.org/10.4028/www.scientific.net/MSF.901.135http://dx.doi.org/10.4028/www.scientific.net/MSF.901.135http://dx.doi.org/10.4028/www.scientific.net/MSF.901.135http://dx.doi.org/10.4028/www.scientific.net/MSF.901.135http://dx.doi.org/10.1063/1.4978154http://dx.doi.org/10.1063/1.4978154http://dx.doi.org/10.1063/1.4978154http://dx.doi.org/10.1063/1.4978154http://dx.doi.org/10.22146/ijc.24891http://dx.doi.org/10.22146/ijc.24891http://dx.doi.org/10.22146/ijc.24891http://dx.doi.org/10.22146/ijc.24891http://dx.doi.org/10.22146/ijc.24891http://dx.doi.org/10.22146/ijc.42317http://dx.doi.org/10.22146/ijc.42317http://dx.doi.org/10.22146/ijc.42317http://dx.doi.org/10.22146/ijc.42317http://dx.doi.org/10.1039/C7RA11824Dhttp://dx.doi.org/10.1039/C7RA11824Dhttp://dx.doi.org/10.1039/C7RA11824Dhttp://dx.doi.org/10.1039/C7RA11824Dhttp://dx.doi.org/10.1039/C7RA11824Dhttp://dx.doi.org/10.1016/j.ejpe.2019.11.004http://dx.doi.org/10.1016/j.ejpe.2019.11.004http://dx.doi.org/10.1016/j.ejpe.2019.11.004http://dx.doi.org/10.1016/j.ejpe.2019.11.004http://dx.doi.org/10.1016/j.ejpe.2019.11.004http://dx.doi.org/10.1016/j.proeng.2013.12.164http://dx.doi.org/10.1016/j.proeng.2013.12.164http://dx.doi.org/10.1016/j.proeng.2013.12.164http://dx.doi.org/10.2306/scienceasia1513-1874.2013.39.492http://dx.doi.org/10.2306/scienceasia1513-1874.2013.39.492http://dx.doi.org/10.2306/scienceasia1513-1874.2013.39.492http://dx.doi.org/10.2306/scienceasia1513-1874.2013.39.492http://dx.doi.org/10.2306/scienceasia1513-1874.2013.39.492http://dx.doi.org/10.1039/B918763Bhttp://dx.doi.org/10.1039/B918763Bhttp://dx.doi.org/10.1016/j.ultsonch.2017.03.030http://dx.doi.org/10.1016/j.ultsonch.2017.03.030http://dx.doi.org/10.1016/j.ultsonch.2017.03.030http://dx.doi.org/10.1016/j.ultsonch.2017.03.030http://dx.doi.org/10.3390/catal7030083http://dx.doi.org/10.3390/catal7030083http://dx.doi.org/10.3390/catal7030083http://dx.doi.org/10.3390/catal7030083http://dx.doi.org/10.1016/j.pce.2011.07.023http://dx.doi.org/10.1016/j.pce.2011.07.023http://dx.doi.org/10.1016/j.pce.2011.07.023http://dx.doi.org/10.1016/j.pce.2011.07.023http://dx.doi.org/10.1016/j.clay.2015.09.021http://dx.doi.org/10.1016/j.clay.2015.09.021http://dx.doi.org/10.1016/j.clay.2015.09.021http://dx.doi.org/10.1016/j.clay.2015.09.021http://dx.doi.org/10.1016/j.clay.2015.02.001http://dx.doi.org/10.1016/j.clay.2015.02.001http://dx.doi.org/10.1016/j.clay.2015.02.001http://dx.doi.org/10.1016/j.clay.2015.02.001http://dx.doi.org/10.1016/j.cjche.2016.04.030http://dx.doi.org/10.1016/j.cjche.2016.04.030http://dx.doi.org/10.1016/j.cjche.2016.04.030http://dx.doi.org/10.1016/j.cjche.2016.04.030http://dx.doi.org/10.1016/j.clay.2010.11.018http://dx.doi.org/10.1016/j.clay.2010.11.018http://dx.doi.org/10.1016/j.clay.2010.11.018http://dx.doi.org/10.1016/j.clay.2010.11.018http://dx.doi.org/10.1016/j.clay.2010.11.018http://dx.doi.org/10.4028/www.scientific.net/NHC.19.46http://dx.doi.org/10.4028/www.scientific.net/NHC.19.46http://dx.doi.org/10.4028/www.scientific.net/NHC.19.46http://dx.doi.org/10.4028/www.scientific.net/NHC.19.46http://dx.doi.org/10.1016/j.matchemphys.2018.03.055http://dx.doi.org/10.1016/j.matchemphys.2018.03.055http://dx.doi.org/10.1016/j.matchemphys.2018.03.055http://dx.doi.org/10.1016/j.matchemphys.2018.03.055www.scienceasia.org