A methodological review on bio-lubricants from vegetable oil based resources

Renewable and Sustainable Energy Reviews 70 (2017) 65–70

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A methodological review on bio-lubricants from vegetable oil based resources Tirth M. Panchal, Ankit Patel, D.D. Chauhan, Merlin Thomas, Jigar V. Patel

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Department of Industrial Chemistry, Institute of Science and Technology for Advanced Studies and Research, Vallabh Vidhyanagar, Gujarat 388120, India

A R T I C L E I N F O

A BS T RAC T

Keywords: Vegetable oil Transesterification Epoxidation Thermomechanical dispersion Bio-based lubricating oil Bio-based grease

Finiteness of global crude oil reserve, rising crude oil prices, and issues related to environment seems to be a reality check for the problems of emerging generations. Present article focuses on lubricating oils as well as lubricating greases developed from vegetable oil. Vegetable oil based lubricants are an attractive alternative to conventional petro based lubricants due to number of their physical properties including renewability, biodegradability, high lubricity and high flash points. Still they have not yet replaced petro based lubricants due to their inappropriate chemical structure, which lags them behind at various odd conditions during applications. The challenges in this field are to improve certain characteristics of vegetable oils without impairing their excellent tribological and environmentally relevant properties. Chemical modification of vegetable oils overcomes the structural problems related to vegetable oils which in turn makes them fit for the application of lubricant. In this review article, we have reviewed the available literature and recently published data related to development of bio-lubricants by chemical modifications of vegetable oils.

1. Role of lubricant Lubricating the moving parts has been known to humans since the invention of the wheel. At that time the primary aim of using a lubricant was to reduce the friction, it can be easily visualized that the use of wooden axles and wheels, or even a combination of metallic wheels and axles would create great amount of friction and wear. Lubrication then becomes the basic need for mechanical machines [54,37]. In any mechanical equipment, the moving parts or the metal surfaces come in contact but they do not usually touch over the whole of their apparent area of contact. In general, they are supported by the surface irregularities which are present even on the most carefully prepared surfaces [73,50,83]. Every working surfaces are rough and this roughness on the surface creates macroscopic ridges and valleys which in turn supports friction. The tribological interactions between exposed sides with the interfacing material and surrounding system may result in loss of material from the surface. The process leading to loss of material due to abrasion is termed as wear. Wear is a process which occur when the surfaces of engineering components are loaded together and are subjected to rolling or sliding motion. The type of friction generated during rolling or sliding motion depends upon the load and the geometry of the substrates. Wear can be minimized by modifying the surface properties of solids by one or more of “surface engineering” processes or by use of lubricants [47,48,85,93].

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Lubrication is the process, or technique employed to reduce wear of one or both surfaces in close proximity, and moving relative to each another, by interposing a substance called lubricant between the surfaces to carry or to help carry the load (pressure generated) between the opposing surfaces. The main purposes of lubrication are (i) to reduce wear and prevent heat loss that results due to contact of surfaces in motion, (ii) to protect it from corrosion and reduce oxidation; (iii) to act as an insulator in transformer applications; and (iv) to act as a sealing agent against dirt, dust, and water. While wear and heat cannot be completely eliminated, they can be reduced to negligible or acceptable levels by the use of lubricants. As heat and wear are associated with friction, both effects can be minimized by reducing the coefficient of friction between the contacting surfaces. Any material used to reduce friction in this way is a lubricant [3,40]. Lubricants are available in liquid, solid, and gaseous forms, amongst which liquid and solid or semisolid are used widely in day to day life. 2. Why bio-lubricants? Trend of using bio-mass for the synthesis of various value added products have been in the priority zone of researchers. Researchers have explored various renewable feed stocks like protein [68,66,67,65], tree leaves [69,31,13], various seaweeds [89,90,49], vegetable oils [41,88,18], coffee pulp [30], paper mill sludge [29], lignocellulose

Corresponding author. E-mail address: [email protected] (J.V. Patel).

http://dx.doi.org/10.1016/j.rser.2016.11.105 Received 29 October 2015; Received in revised form 26 August 2016; Accepted 2 November 2016 1364-0321/ © 2016 Elsevier Ltd. All rights reserved.

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being used absolutely in many different ways.

and other agro-residues [46,28,8,1] for the synthesis of bio-plastic, biodiesel, bio-lubricant, bio-adsorbent, bio-stimulants and bio-ethanol. These bio based products are now being used successfully at commercial level in many developed countries. If one thinks of lubricants today, the first thing that flashes in mind is the petroleum oil. Petroleum oil components continue to form the major proportion of lubricants. The major source of almost all lubricants is the lube fraction which is obtained from crude petroleum [55,51]. Wide use of petro based lubricants is because they have the longest drain interval i.e. the operating life of a lubricant, which decreases the frequency of breakdown time of the machine as completely changing the lubricant takes a significant amount of time [87]. Lubricants and functional fluids are omnipresent due to their widespread use and they thus pollute the environment in small, widelyspread amounts and rarely in large, localized quantities. Although petroleum based lubricants possess many useful physical properties, they are also non- renewable and toxic to the environment [53]. Industrial equipment's used in offshore drilling or agriculture require machinery to be in close proximity with a water source, and using petro based lubricants can be dangerous to the surroundings. Improper disposal of used petro based lubricants contaminates water bodies, cause infections and affects vitally on the survival of aquatic ecosystem. Numerous environmental groups and nature clubs have pressured industrial groups to use bio based lubricants instead of petro based lubricants in these situations [4,39,82]. Major portion of the lubricants consumed worldwide ends up in polluting the environment, many efforts are made to minimize spillages and evaporation. These high lubricant losses into the environment were behind the development of environmentally friendly bio based lubricants [55]. Also the idea that oil soon may no longer be available, industries have been searching for a cheap, renewable source of lubricant. As we know that non edible uses of vegetable oils have grown little during the last few decades. Although some markets have been explored based on vegetable oil oriented products, still there are many bright scopes of expansion in the field of vegetable oils [21]. Many countries like India, Sri Lanka, Bangladesh, Nepal etc. have great potential of producing edible and non-edible tree borne oils, which remain untapped and can be used as potential source for vegetable oil based lubricants. Increased markets for such uncommon seeds and oil could increase farmer incomes and maximize the application of agriculture products [84]. Vegetable oils have superb environmental credentials, such as being inherently biodegradable, having low ecotoxicity and low toxicity towards humans, being derived from renewable resources, and contributing no volatile organic chemicals [75], due to which they are used in various industrial applications such as emulsifiers, lubricants, plasticizers, surfactants, plastics, solvents and resins. Although vegetable oils possess many desirable characteristics, currently they are not widely used as lubricant base oils. Largely this is due to undesirable physical properties of most vegetable oils viz. poor oxidation stability, poor low temperature properties, poor viscosity index, etc. [62,59]. Just like two sides of a coin, vegetable oil based lubricants also have their own merits and demerits, they have outstanding physical properties which justifies them as lubricants, but have poor thermo-oxidative property which restricts them to be used as lubricating agent at elevated temperatures [55]. Much research is being carried out to improve the thermo-oxidative property, so that they may compete as an economical alternative with petro based lubricants. Currently there are steps being taken towards creating an economy that prefers a bio based lubricant through policy, but there are complications in the perception of bio based oil and the allocation of arable land. The world cannot completely switch over to bio based lubricants, it must be a gradual process requiring the collaboration of government support, agriculture, industry and research. Globally, crude oil based products have dominated the lubricants market. But this progress is limited to the last century. The application of natural oils and fat as lubricating agents are

3. Vegetable oils as lubricating oil Can vegetable oils make good lubricant base stocks? Research conducted till date indicates that chemically and genetically modified vegetable oils have excellent potential to perform adequately as lubricants. Vegetable oils have been used as lubricants for machinery and transportation vehicles for a prolonged period of time before the discovery of petroleum resources. Petroleum, primarily being cheaper and having improved performance, quickly replaced vegetable oils as the lubricant. Now, with increased petroleum costs, decreased petroleum reserves, and environmental concerns as major factors, vegetable oils as lubricating agents are making a slow but steady comeback. In the past decade, the initial applications have been niche markets such as chain saws, track lubricants, and other total loss lubricants. Some technical and logistic concerns have been marked regarding the ability to maintain consistent profile of vegetable oils that would meet the final application and performance specifications. A lot of development and research is being carried out to meliorate the physicochemical properties of vegetable oils so that they may compete with petroleum based lubricants. Number of plant based lubricants have been developed for various sectors of industry ( Tables 1-3). Compared to petroleum based lubricants, vegetable oils in general possess high flash point, high viscosity index, higher lubricity, low evaporative losses, and good metal adherence. The presence of a polar group with a long hydrocarbon chain makes vegetable oil amphiphilic surfactant by nature, allowing it to be used as a boundary lubricant [44]. The molecules have strong affinity for and interact strongly with metal surfaces. The long hydrocarbon chain is oriented away from the metal surface to form a monomolecular layer with excellent boundary lubrication properties [43,42,2]. Various routes of chemical modification of vegetable oils have been developed with an aim to prepare a perfect bio degradable lubricant. Chemical modification of vegetable oil enhances its thermal as well as oxidation stability, which help them to withstand within wide operating conditions. The methods for development of vegetable oil based lubricants are as follows. 4. Transesterification of vegetable oils Transesterification is a reaction in which an ester is transformed into another ester through interchange of the alkyl group. Transesterification of vegetable oils yields to synthesis of various fatty Table 1 Specific applications of various vegetable oil [81,38] Vegetable oil

Application

Canola oil

Hydraulic oils, tractor transmission fluids, metal working fluids, food grade lubes, penetrating oils, chain bar lubes Gear lubricants, greases Gas engine oils Automotive lubricants Rolling lubricant,-steel industry, grease Chain saw bar lubricants, air compressor-farm equipment, Biodegradable greases. Light-colored paints, diesel fuel, resins, enamels Coating, paints, lacquers, varnishes, stains, Lubricants, biodiesel fuel, metal casting/working, printing inks, paints, coatings, soaps, shampoos, detergents, pesticides, disinfectants, plasticizers, hydraulic oil Grease, cosmetic industry, lubricant applications Grease, intermediate chemicals, surfactants Grease, diesel fuel substitutes Cosmetics and motor oil Steam cylinder oils, soaps, cosmetics, lubricants, plastics

Castor oil Coconut oil Olive oil Palm oil Rapeseed oil Safflower oil Linseed oil Soybean oil

Jojoba oil Crambe oil Sunflower oil Cuphea oil Tallow oil

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Table 2 Various methods of bio-lubricant from vegetable oil by transesterification. Oil/ Fatty acid/ Fatty acid methyl esters

Alcohol

Oil/ Fatty acid to Alcohol ratio

Catalyst

Reaction condition

Yield

Reference

150 °C, 3 h 110 °C, 1–1.5 mbar. 20mbar, T=120 °C, less than 1h 110 °C, 8 h, Reduced pressure 3.3kPa Under vaccumm, boiling temperature Under vaccumm, boiling temperature Under vaccumm, boiling temperature 120 °C, 2.5 h 170 °C, 8 h

98.6% 98% 98%

[6] [32] [94]

99%

[91]

94.5%

[63]

93.1%

[63]

95%

[63]

– 72%

[11] [12]

170 °C, 8 h

78%

[12]

140 °C, 4 h, 300 rpm 140 °C, 4 h, 300 rpm 140 °C, 4 h, 300 rpm 140 °C, 4 h, 300 rpm 40 °C, magnetic stirring

93.9% 98.6% 84.6% 81.7% 94%

[60] [60] [60] [60] [19]

Jathropha oil Palm oil methyl ester Palm oil methyl ester

Trimethylol propane Triemthylol propane Triemthylol propane

4:1 10:1 3.9:1

H2SO4 (2%) NaOCH3 NaOCH3

Rapeseed oil methyl ester

Trimethylol propane

17.1:5.3

NaOCH3(0.5%)

Karanja oil methyl ester

Hexanol

1:1

NaOCH3 (3%)

Karanja oil methyl ester

Octanol

1.1

NaOCH3 (3%)

Karanja oil methyl ester

Neo-pentyl glycol

1:0.5

NaOCH3(3%)

Jathropha Oil Sunflower Oil

Ethylene glycol n-Propanol

3.5:1 1:15

Sunflower Oil

n-Octanol

1:15

Stearic acid Oleic acid Linoleic acid Oleic acid Sunflower oil

1-octanol 1-octanol 1-octanol Hexadecanol Butanol

6.25:7.5 6.25:7.5 6.25:7.5 6.25:7.5 1:5

NaOCH3 (0.8%) Heteropolyacids supported by Clay (K −10) Heteropolyacids supported by Clay (K −10) Sulfated zirconia Sulfated zirconia Sulfated zirconia Sulfated zirconia Rhizomucor miehei immobilised lipase

than the base-catalyzed reaction has been one of the main factor. In this method transesterification process is catalyzed by acids, preferably by sulfonic, sulfuric acids, hydrochloric acids and phosphoric acids which can lead to corrosion of reactors. Though the yield of product obtained using acid catalyst is high, the rate of reaction is slow, requiring, typically, temperatures above 100 °C and more than 3 h to reach complete conversion. Excess of the alcohol ensures the formation of the alkyl esters. An excessive amount of alcohol makes the recovery of the glycerol difficult, hence it is important to use optimum alcohol to oil ratio [23,33,22,78].

acid alkyl esters by reacting vegetable oils with various lower and higher chain length alcohols [95,7]. The reaction can be conducted as acid-catalyzed or base-catalyzed. The final product i.e. fatty acid alkyl esters derived from vegetable oils can be used as lubricating agents. The stoichiometric reaction requires 1 mol of a triglyceride and 3 mol of the alcohol. However, an excess of the alcohol is used to increase the yields of the alkyl esters and to allow its phase separation from the glycerol formed. Various factors to be considered during transesterification are alcohol to oil molar ratio, temperature of the reaction, type of catalyst (alkaline or acid), catalyst concentration, purity of the reactants and free fatty acid content have an influence on the course of the transesterification as they are the key factors that effects the transesterification.

4.2. Base-catalyzed transesterification A proposed mechanism for base catalyzed transesterification states that esters, in the presence of bases forms an anionic intermediate which can dissociate back to original ester or form new ester. Basecatalyzed transesterification of vegetable oils proceeds at a faster rate of reaction as compared to acid-catalyzed reaction [23,22]. Due to this reason, along with an advantageous fact that base catalysts merely

4.1. Acid-Catalyzed transesterification Acid-catalyzed transesterification method is not practiced widely in commercial applications as compared to the base-catalyzed method. The fact that the acid-catalyzed reaction is roughly 4000 times slower Table 3 Various reported methods of bio-lubricant by epoxidation of vegetable oils. Oil

Acid

Cotton seed Cotton seed Soybean Jathropha Hemp Mahua Canola Rubber seed Karanja Neem oil Tobacco seed oil Cotton seed Soybean oil Sunflower oil Cotton seed Soybean Canola Rice bran

Glacial acetic Formic acid acetic acid acetic acid Glacial acetic Glacial acetic Acetic acid Formic acid Glacial acetic Glacial acetic Glacial acetic Formic acid Formic acid Formic acid Glacial acetic Glacial acetic Acetic acid Formic acid

acid

acid acid

acid acid acid

acid acid

H2O2 concentration

Ethylene unsaturation: Acid:H2O2

Catalyst

Reaction Condition

Yield

Reference

50% 50% 50% 50% 30% 30% 30% 30% 30% 30% 30% 30% 30% 30% 30% 35% 50% 30%

2.5:0.75:1.1 2.5:0.75:1.1 2.0:0.75:1.3 2.0:0.75:1.3 1.00:0.70:1.00 2.00:0.75:0.8 1:0.5:1.5 2:1:4 1:0.5:1.5 1:0.5:2 1:0.7:2 1:0.15:1 1:2:20 1:2:20 1:0.5:2 1:0:1 1:0.5:2 1:0.5:1.5

H2SO4, 2% H2SO4, 2% H2SO4, 2% H2SO4, 2% Amberlite IR−120 H2SO4, 2% Amberlite IR−120 – H2SO4, 2% H2SO4, 2% H2SO4, 2% – – – H2SO4, 2% Novozyme 435 Lipase b. 20.8% Amberlite IR120 H2SO4, 3%

60 °C, 8 h, 2400 rpm. 60° C, 8 h, 2400 rpm. 60° C, 10 h, 1800 rpm 60° C, 10 h, 1800 rpm 75° C, 8 h, 150 rpm 85 °C, 3.5 h 1500 rpm 65°C, 60° C, 5 h 70° C, 6 h 1500 rpm 65° C, 6 h, 2000 rpm 65° C, 6 h, 2000 rpm 60° C, 5 h 40° C, 20 h 40° C, 20 h 60° C, 6 h, 850 rpm 60° C, 24 h, 350 rpm 75° C, 5.5 h 60° C, 6 h, 1600 rpm

93.9% 94.6% 83.3% 87.4% 88% 83% 90% 94% 80% 86% 90% – – – 81% 96.3% 93% 92%

[17] [17] [56] [56] [16] [25] [58] [24] [26] [64] [64] [45] [14] [14] [77] [92] [57] [71]

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6. Biodegradable grease

Table 4 Various grades of grease classified by NLGI. NLGI Grade

Worked penetration after 60 strokes at 25 °C.

Appearance

Consistency food analog

000 00 0 1 2 3 4 5 6

445–475 400–430 355–385 310–340 265–295 220–250 175–205 130–160 85–115

Fluid Semi-fluid Very soft Soft Normal Firm Very firm Hard Very hard

Cooking oil Apple sauce Brown mustard Tomato paste Peanut butter Vegetable shortening Frozen yogurt Smooth pate Cheddar cheese

Grease is an effective means of providing lubrication to the machine component. Although liquid lubricants flow easily, they require a reservoir to contain their volume. Solid lubricants on the other hand require direct contact at the point of lubrication in order to effectively deliver lubrication. Greases are semi-solid and can deliver the benefits of liquid lubricants without requiring a reservoir, and also the benefits of solid lubricants by maintaining their body structure. In applications like the wheel bearing of an automobile where excessive heat is generated, liquid lubricants would thin down and can leak out of the bearing seals. The wheel bearing is a good example for using grease. Lubricating greases are semi-solid colloidal dispersions of a thickening agent in a liquid lubricant matrix. They owe their consistency to a gelforming network where the thickening agent is dispersed in the lubricating base fluid. Greases are classified on their consistency, depending on their consistency. NLGI, National lubricating grease institute, a pioneering institute in the grease area has classified grease according to its grades (Table 4). The fluid base oil performs the actual lubrication, which can be petroleum (mineral) oil, synthetic oil, or vegetable oil while, the thickener gives grease its characteristic consistency (hardness) that is sometimes thought of as a “three-dimensional fibrous network” or “sponge” that holds the oil in place [61]. Therefore, the base fluid imparts lubricating properties to the grease while the thickener, essentially the gelling agent, holds the matrix together. This is a twostage process. First, the absorption and adhesion of base oil in the soap structure results, and secondly, there is a swelling of the soap structure when the remaining oil is added to the reaction mixture. The incorporation of soap throughout the oil matrix is done by thermomechanical dispersion. A typical grease composition contains 60–95% base fluid (mineral, synthetic, or vegetable oil), 5–25% thickener (common thickeners are fatty acid soaps and organic or inorganic non-soap thickeners), and 0–10% additives (antioxidants, corrosion inhibitors, anti-wear/extreme pressure, antifoam, tackiness agents, etc.) [21]. Additives enhance performance and protect the grease and lubricated surfaces. Development of vegetable oil-based greases has been an area of active research for several decades [20,34]. Technical progress taking place in industry and agriculture has caused an intensive exploitation of natural resources like mineral oil. Global grease consumption is estimated at 1,296 KT of which 691 KT accounts for industrial applications. Petroleum oil based greases accounts for about to 90% of the global demand, while 9% of synthetic esters are consumed and only 1% of bio degradable base oils are used for manufacturing of greases. It is assumed that the demand for global consumption of grease in industrial application will rise up to 758 KT till 2017 [63,80]. The search for environmentally friendly materials to replace mineral oil is currently being considered a top priority research in the fuel and energy sector. This emphasis is largely due to the rapid depletion of world fossil fuel reserves and increasing concern for environmental pollution from excessive mineral oil use and disposal. Renewable resources like seed oils and their derivatives are being considered as potential replacements for mineral oil base stocks in certain lubricant applications, where immediate contact with the environment is anticipated. The nontoxic and readily biodegradable characteristics of vegetable oil based lubricants pose less danger to soil, water, flora and fauna in case of accidental spillage or during disposal [86]. Bio based grease are manufactured by replacing the petroleum base oil by chemically modified vegetable oil. A work conducted by Panchal. et. al. displays a good example of chemical modification of non-traditional vegetable oils and using it in formulation of bio based grease. Samples of grease were prepared using chemically modified vegetable oil as base oil and lithium-12-hydroxy stearate as thickener. The comparative study of bio based grease and the petroleum based grease done by the researchers shows that, vegetable oil based grease are comparatively good in load carrying

corrode industrial apparatus than acidic catalysts, most commercial transesterifications are conducted by alkaline catalysts, such as alkaline metal alkoxides and hydroxides [23,22,79] as well as sodium or potassium carbonates [10]. The alkalis used generally includes sodium and potassium hydroxides, carbonates, and alkoxides such as methoxide, ethoxide, propoxide, and butoxide [5], amongst which alkaline metal alkoxides are the most active catalysts, since they give very high yields ( > 98%) in short reaction times (30 min) even if they are applied at low molar concentrations (0.5 mol%). However, they require the absence of water which makes them inappropriate for typical industrial processes [9]. Alkaline metal hydroxides (KOH and NaOH) are cheaper than metal alkoxides, but less active. They can give the high conversions of esters just by increasing their concentration from 1% to 2%. Various methods of transesterification of vegetable oil to develop bio lubricant are listed below.

5. Epoxidation The term epoxide can be defined as cyclic ethers which consist of three elements in the epoxide ring. Epoxidation is a crucial reaction for unsaturated fatty acids which is often performed in situ. The double bonds in the vegetable oils are used as reactive sites in coating applications and they can also be functionalized by epoxidation. This unsaturation is a drawback for vegetable oil and limits its use as lubricant at high temperature applications. The utilization of epoxidized vegetable oil has become more common in the past few years. Moreover, plasticizers and additives for polymer PVC derived from vegetable oil based have been shown to have improved performance in terms of high resistance to heat and light [76]. Epoxidized oil contains epoxide groups or oxirane rings. The general process for the synthesis of the epoxide groups is known as an epoxidation reaction wherein an alkene is reacted with an organic peroxy acid. Epoxidation methods vary from case to case depending on the nature of reactants and catalysts used for epoxidation. To produce epoxides from olefinic type of molecules, the available methods are epoxidation with percarboxylic acids [27], can be catalyzed by acids or by enzymes [72,74]. In situ epoxidation reaction generally takes place in two steps: (i) formation of peroxy acid, and (ii) reaction of peroxy acid with the unsaturated double bond. The conversion of ethylenic unsaturation in to epoxide depends upon various factors like ratio of ethylenic unsaturation to per carboxylic acids, temperature, catalyst, catalyst concentration, rpm, and addition time of H2O2. Addition of H2O2 is done slowly to avoid zones of high peroxide concentration which leads to formation of explosive mixtures [15,26]. The main purpose of this study was to promote the use of vegetable oil and develop value added products form locally available renewable resources in India. Vegetable oils such as rice-bran, cottonseed, groundnut, sunflower, rapeseed, sesame, palm kernels, coconut, linseed, castor, sal, neem, karanja are easily available in India. Various methods for epoxidation of vegetable oils are tabulated below. 68

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can be explored successfully for the development of lubricants and greases having competitive performance as compared to petroleum based lubricants.

capacity and shows good tribological properties under extreme pressure [63]. Kumar et al. have conducted a work regarding compatibility of biobased grease with mineral oil based grease. Compatibility of greases was evaluated by the protocol described in ASTM D-6185-10. As per method, binary mixtures in 10:90, 50:50 and 90:10 ratios were prepared by physical mixing. The reported work shows that of canola oil based aluminum complex, lithium complex and lithium-calcium greases with aluminum complex greases are shows good compatibility with petroleum based calcium sulfonate complex, and lithium complex greases. The compatibility of greases plays a crucial role in actual applications like centralized lubrication systems and applications where complete cleaning or replacement of existing grease is very difficult. If two greases are incompatible, it is obvious that the mixed grease changes its physicochemical property and may lead to the premature failure of bearing/equipment [52]. Recently a work published by Ponnekanti Nagendramma and Prashant Kumar describes formulation of lubricating grease using Jatropha residual oil as base oil and lithium stearate and oleate soaps as thickeners and zinc dialkyldithiophosphate as multifunctional additive. The performance parameters of weld load and wear scar diameter obtained with the residual oil grease is better than that of commercial grease [70]. Hocine et al. reported the applications of biodegradable greases in open gears, draglines, drag gearings, mill liner application of rolling mills, tunnel boring machines, etc [35]. Honary reported bio-based grease for curve rail and fifth wheel lubricants for the lubrication of moving components like flanged wheels of railway locomotives [36]. Because of the short life expectancy of vegetable oils and the still limited availability of high performance biodegradable additives, at present it is only possible to use vegetable-oil-based lubricating greases in relatively open, or total-loss lubricated systems like in agricultural and construction machinery, waste water purification plants, open gears and some food processing machinery.

References [1] Adekunle A, Orsat V, Raghavan V. Lignocellulosic bioethanol: a review and design conceptualization study of production from cassava peels. Renew Sustain Energy Rev 2016;64:518–30. [2] Adhvaryu A, Sung C, Erhan SZ. Fatty acids and antioxidant effects on grease microstructures. Ind Crops Prod 2005;21:285–91. http://dx.doi.org/10.1016/j.indcrop.2004.03.003. [3] Ahmed N, Nassar A. Lubr Lubr 2013. [4] Aji MM, Kyari SA, Zoaka G. Comparative studies between bio lubricants from jatropha oil, neem oil and mineral lubricant (engen super 20w/50). Appl Res J 2015;1(4):1252–7. [5] Anastopoulos G, Zannikou Y, Stournas S, Kalligeros S. Transesterification of vegetable oils with ethanol and characterization of the key fuel properties of ethyl esters. Energies 2009;2:362–76. [6] Arbain N, Salimon J. Synthesis and characterization of ester trimethylolpropane based jatropha curcas oil as biolubricant base stocks. J Sci Technol 2011;2:47–58. [7] Asadauskas S, Erhan SZ. Depression of pour points of vegetable oils by blending with diluents used for biodegradable lubricants. J Am Oil Chem Soc 1999;76:313–6. http://dx.doi.org/10.1007/s11746-999-0237-6. [8] Asgher M, Bashir F, Iqbal HM. A comprehensive ligninolytic pre-treatment approach from lignocellulose green biotechnology to produce bio-ethanol. Chem Eng Res Des 2014;92(8):1571–8. [9] Ayhan D. Biodiesel a Realistic Fuel Alternative for Diesel Engines, ISBN-13: 9781846289941; 2008. [10] Bajwa U, Bains G. Studies on the glycerolysis of groundnut oil and cottonseed oil. J Food Sci Technol 1987;24:81–3. [11] Bilal S, Mohammed-Dabo I, Nuhu M, Kasim S, Almustapha I, Yamusa Y. Production of biolubricant from Jatropha curcas seed oil. J Chem Eng Mater Sci 2013;4(6):72–9. http://dx.doi.org/10.5897/JCEMS2013.0164. [12] Bokade V, Yadav G. Synthesis of bio-diesel and bio-lubricant by transesterification of vegetable oil with lower and higher alcohols over heteropolyacids supported by clay (K-10). Process Saf Environ Prot 2007;85(5):372–7. http://dx.doi.org/ 10.1205/psep06073. [13] Boudrahem F, Aissani-Benissad F, Soualah A. Adsorption of lead (II) from aqueous solution by using leaves of date trees as an adsorbent. J Chem Eng Data 2011;56(5):1804–12. [14] Campanella A, Rustoy E, Baldessari A, Baltanás M. Alubricants from chemically modified vegetable oils. Bioresour Technol 2010;101:245–54. http://dx.doi.org/ 10.1016/j.biortech.2009.08.035. [15] Clark D. Peroxides and peroxide-forming compounds. Chem Heal Saf 2001;8:12–22. [16] Cooney T, Cardona F, Tran-Cong T. Kinetics of in situ epoxidation of hemp oil under heterogeneous reaction conditions: an overview with preliminary results. Proc 1st Int Post Conf Eng Des Dev Built Environ Sustain Wellbeing 2011:106–11. [17] Dinda S, Patwardhan AV, Goud VV, Pradhan NC. Epoxidation of cottonseed oil by aqueous hydrogen peroxide catalysed by liquid inorganic acids. Bioresour Technol 2008;99:3737–44. http://dx.doi.org/10.1016/j.biortech.2007.07.015. [18] Dixit S, Rehman A. Linseed oil as a potential resource for bio-diesel: a review. Renew Sustain Energy Rev 2012;16(7):4415–21. [19] Dossat V, Combes D, Marty A. Lipase-catalysed transesterification of high oleic sunflower oil. Enzym Micro Technol 2002;30:90–4. http://dx.doi.org/10.1016/ S0141-0229(01)00453-7. [20] Dresel WH. Biologically degradable lubricating greases based on industrial crops. Ind Crops Prod 1994;2:281–8. [21] Erhan, S. Industrial uses of vegetable oils. AOCS. 2005 [22] Freedman B, Pryde EH, Mounts TL. Variables affecting the yields of fatty esters from transesterified vegetable oils. J Am Oil Chem Soc 1984;61:1638–43. http:// dx.doi.org/10.1007/BF02541649. [23] Freedman B, Butterfield RO, Pryde EH. Transesterification kinetics of soybean oil 1. J Am Oil Chem Soc 1986;63:1375–80. http://dx.doi.org/10.1007/BF02679606. [24] Gamage PK, O & apos , Brien M, Karunanayake L. Epoxidation of some vegetable oils and their hydrolysed products with peroxyformic acid - optimised to industrial scale. J Natl Sci Found Sri Lanka 2009;37:229–40. http://dx.doi.org/10.4038/ jnsfsr.v37i4.1469. [25] Goud VV, Patwardhan AV, Pradhan NC. Studies on the epoxidation of mahua oil (Madhumica indica) by hydrogen peroxide. Bioresour Technol 2006;97:1365–71. http://dx.doi.org/10.1016/j.biortech.2005.07.004. [26] Goud VV, Pradhan NC, Patwardhan AV. Epoxidation of karanja (Pongamia glabra) oil by H2O2. J Am Oil Chem Soc 2006;83:635–40. http://dx.doi.org/10.1007/ s11746-006-1250-7. [27] Guenter S, Rieth R, Rowbottom K. Ullmann's Encyclopedia of Industrial Chemistry. 6th ed., 2003;12 p.269–284. [28] Gupta A, Verma JP. Sustainable bio-ethanol production from agro-residues: a review. Renew Sustain Energy Rev 2015;41:550–67. [29] Gurram R, Al-Shannag M, Lecher N, Duncan S, Singsaas E, Alkasrawi M. Bioconversion of paper mill sludge to bioethanol in the presence of accelerants or hydrogen peroxide pretreatment. Bioresour Technol 2015;192:529–39. [30] Gurram R, Al-Shannag M, Knapp S, Das T, Singsaas E, Alkasrawi M. Technical possibilities of bioethanol production from coffee pulp: a renewable feedstock.

7. Conclusion Commercially, the act of using bio-based lubricant has been appreciated notably where the environmental concerns are recognized as being prime importance. This review largely covers various reported methods for the development of bio-based lubricants from vegetable oil resources. The methods reported covers in-detail description regarding the use of various raw materials, type of catalyst, use of other reactants for chemical modification, catalyst concentration, pressure and temperature conditions and other important reaction parameters for the modification of vegetable oils to be used as lubricants and grease. Challenges in this field are related to development of a globally available biodegradable base stock, their constant supply along with ideal physicochemical properties. Any change in physicochemical properties could lead to change in the yield of the final product. This could be overcome by tuning the methods of chemical modification accordingly. Similarly evaluation of properties for final product is equally important, in this case ASTM is reviewing the current products available today and the required testing are being developed for defining the performance criteria for biodegradable fluids. However, the development of various biodegradable industrial lubricants could lead to a major revolution in the world lubricant market. The laws regarding environmental regulations and disposal issues are being more and more stringent which could enforce the users to shift towards the use of biodegradable products. In near future of 15–20 years, the share of environment friendly lubricant market would rise to approximately 15% and in some regions up to 30%. The world lubricant market will see a lot of replacements in the existing products within next 10–15 years and it certainly will remain an interesting field of development for the lubricant manufacturers. The literature reviewed in the present article suggests that vegetable oil based resources 69

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T.M. Panchal et al.

[31] [32]

[33]

[34] [35] [36] [37] [38] [39] [40] [41] [42] [43] [44] [45]

[46]

[47]

[48] [49]

[50] [51]

[52] [53] [54] [55] [56]

[57]

[58]

[59]

[60]

[61] [62] [63]

[64]

Clean Technol Environ Policy 2015;18:269–78. http://dx.doi.org/10.1007/ s10098-015-1015-9. Hameed BH. Removal of cationic dye from aqueous solution using jackfruit peel as non-conventional low-cost adsorbent. J Hazard Mater 2009;162(1):344–50. Hamid HA, Yunus R, Rashid U, Choong TSY, Al-Muhtaseb AH. Synthesis of palm oil-based trimethylolpropane ester as potential biolubricant: chemical kinetics modeling. Chem Eng J 2012;200–202:532–40. http://dx.doi.org/10.1016/ j.cej.2012.06.087. Harrington KJ, D´Arcy-Evans C. Transesterification in situ of sunflower seed oil. Ind Eng Chem Prod Res Dev 1985;24:314–8. http://dx.doi.org/10.1021/ i300018a027. Hissa R, Monterio JC. Manufacture and evaluation of Li-greases made from alternate base oils. NLGI Spokesm 1983;3:426–32. Hocine F, Medrano A, Cisler B. Biodegradable open gear lubricant. NLGI Spokesm 2004;67(12):121–35. Honary L. A Study of Compatibility of Fully Formulated Bio-based and Conventional Greases. In: Proceedings of the 78th NLGI Annual Meeting; 2011. Honary L, Richter E. Biobased Lubr greases: Technol Prod 2011. Hsien W. Towards Green Lubr Mach 2015. http://dx.doi.org/10.1007/978-981287-266-1_2. Ing A. Biobased lubricants: a viability study. In: Proceedings 53rd Annu Meet ISSS2009, Brisbane, Aust 2009. Iqbal M. Tribology: science of lubrication to reduce friction and wear. Int J Mech Eng 2014;3(3):648–68. Issariyakul T, Dalai AK. Biodiesel from vegetable oils. Renew Sustain Energy Rev 2014;31:446–71. Jahanmir S, Beltzer M. Effect of additive molecular structure on friction coefficient and adsorption. J Tribol 1986;108:109–16. Jahanmir S, Beltzer M. An adsorption model for friction in boundary lubrication. ASLE Trans 1986;29:423–30. Jain A, Suhane A. Research approach & prospects of non edible vegetable oil as a potential resource for biolubricant-a review. Adv Eng Appl Sci Int J 2012;1:23–32. Jia LK, Gong LX, Ji WJ, Kan CY. Synthesis of vegetable oil based polyol with cottonseed oil and sorbitol derived from natural source. Chin Chem Lett 2011;22:1289–92. http://dx.doi.org/10.1016/j.cclet.2011.05.043. Jørgensen H, Kristensen JB, Felby C. Enzymatic conversion of lignocellulose into fermentable sugars: challenges and opportunities. Biofuels, Bioprod Bioref 2007;1(2):119–34. Kakirde A, Tripathi K, Achwal V, Tripathi S. Investigation of mechanical and tribological properties of polymer composite material: a review. IUP J Mech Eng 2013;6(3):55. Kato K. Classification of wear mechanisms/models. Wear: Mater Mech Pract 2006:9–20. Khan W, Rayirath UP, Subramanian S, Jithesh MN, Rayorath P, Hodges DM, Critchley AT, Craigie JS, Norrie J, Prithiviraj B. Seaweed extracts as biostimulants of plant growth and development. J Plant Growth Regul 2009;28(4):386–99. Kragelsky I, Dobychin M, Kombalov V. Frict wear: Calc Methods 2013. Kučera M, Hnilicová M, Turis J, Semanova P. The experimental research of physicochemical and tribological characteristics of hydraulic oils with a low environmental impact. Acta Fac Tech 2013;2:25–31. Kumar A, Mallory B. How friendly are bio-based greases with other greases?. NLGI Spokesm 2013;77(2):34–47. Luther R. Lubricants, 3. environmental aspects. Ullmann'S Encycl Ind Chem 2002. Madius C, Smet W. Grease fundamentals: covering the basic of lubricating grease.; axel, christiansson. The Netherlands: Heijningen; 2009 〈www.axelch.com〉. Mang T, Dresel W. Lubr Lubr 2007. http://dx.doi.org/10.1002/9783527610341. Meyer P, Techaphattana N, Manundawee S, Sangkeaw S, Junlakan W, Tongurai C. Epoxidation of soybean oil and Jatropha oil. thammasat Int J Sci Technol 2008;13:1–5. Monono E, Haagenson DM, Wiesenborn DP. Characterizing the epoxidation process conditions of canola oil for reactor scale-up. Ind Crops Prod 2015;67:364–72. Mungroo R, Pradhan NC, Goud VV, Dalai AK. Epoxidation of canola oil with hydrogen peroxide catalyzed by acidic ion exchange resin. J Am Oil Chem Soc 2008;85:887–96. http://dx.doi.org/10.1007/s11746-008-1277-z. Nagendramma P, Kaul S. Development of ecofriendly/biodegradable lubricants: an overview. Renew Sustain Energy Rev 2012;16:764–74. http://dx.doi.org/10.1016/ j.rser.2011.09.002. Oh J, Yang S, Kim C, Choi I, Kim JH, Lee H. Synthesis of biolubricants using sulfated zirconia catalysts. Appl Catal A Gen 2013;455:164–71. http://dx.doi.org/ 10.1016/j.apcata.2013.01.032. Omar FA, Ismail A. Production of grease from spent lubricant [PhD diss.]. Universiti Malaysia Pahang; 2009. Panchal T, Chauhan D, Thomas M, Patel J. Synthesis and characterization of bio lubricants from tobacco seed oil. Res J Agric Environ Manag 2013;3(2):97–105. Panchal T, Chauhan D, Thomas M, Patel J. Bio based grease A value added product from renewable resources. Ind Crops Prod 2015;63:48–52. http://dx.doi.org/ 10.1016/j.indcrop.2014.09.030. Panchal T., Patel A., Thomas M., Patel J. Non-traditional vegetable oils: a potential

[65]

[66] [67]

[68]

[69]

[70] [71] [72]

[73] [74]

[75] [76] [77] [78]

[79]

[80] [81]

[82] [83] [84] [85] [86] [87] [88]

[89] [90]

[91]

[92]

[93] [94]

[95]

70

source for green lubricants. In: Proceedings of the 106th AOCS Annual Meeting and Industry Showcases organized by AOCS 2015. Patel A, Rudakiya D, Gupte A, Patel J Maize gluten based Bio-plastic sheets: fabrication, characterization and biodegradation behavior. In: Proceedings of International Conference on Chemical Industry. p. 230–245. ISBN: 978-93-8121284-4. Patel A, Raj M, Gupte A, Patel J. Bio-Plastics: a value added products from renewable resources. Asian Acad Res J Multidiscip 2015;2(3):166–84. Patel A, Panchal T, Rudakiya D, Gupte A, Patel J. Fabrication of bio-plastics from protein isolates and its biodegradation studies. Int J Chem Sci Technol 2016;1(3):1–13. Patel A, Panchal T, Thomas M, Gupte A, Patel J. Preparation and characterization of biodegradable packaging film using groundnut protein isolate. Eur BiomassConf Exhib Proc 2016:1048–55. http://dx.doi.org/10.5071/ 24thEUBCE20163BO.15.5. Patel SP, Thomas M, Patel AV, Patel JV. Study of KOH impregnated jack fruit leaf based carbon as adsorbent for treatment of wastewater contaminated with nickel. Int J Recent Trends Eng Res 2016;2(7):219–29. Ponnekanti N, Kumar P. Eco-friendly multipurpose lubricating greases from vegetable residual oils. Lubricants 2015;3(4):628–36. Purwanto E. The synthesis of rice bran oil through epoxidation and hydroxylation reactions [MS diss.]. Australia: The University of Adelaide; 2010. Rios LA, Weckes P, Schuster H, Hoelderich WF. Mesoporous and amorphous Tisilicas on the epoxidation of vegetable oils. J Catal 2005;232:19–26. http:// dx.doi.org/10.1016/j.jcat.2005.02.011. Rothbart H, Brown T. Mechanical design handbook, second edition. McGraw hill; 2006. Rüsch Gen, Klaas M, Warwel S. Complete and partial epoxidation of plant oils by lipase-catalyzed perhydrolysis. Ind Crops Prod 1999;9:125–32. http://dx.doi.org/ 10.1016/S0926-6690(98)00023-5. Salimon J, Salih N. Chemical modification of oleic acid oil for biolubricant industrial applications. Aust J Basic Appl Sci 2010;4:1999–2003. Saurabh T, Patnaik M, Bhagat SL, Renge VC. Epoxidation of vegetable oils: a review. Int J Adv Eng Technol 2011;2:491–501. Saurabh T, Patnaik M, Bhagat SL, Renge VC. Studies on the synthesis of biobased epoxide using cottonseed oil. Int J Adv Eng Res Stud 2012;2:279–84. Schuchardt U, Sercheli R, Vargas RM. Transesterification of vegetable oils: a review. J Braz Chem Soc 1998;9:199–210. http://dx.doi.org/10.1590/S010350531998000300002. Schwab AW, Bagby MO, Freedman B. Preparation and properties of diesel fuels from vegetable oils. Fuel 1987;66:1372–8. http://dx.doi.org/10.1016/00162361(87)90184-0. Sharma P, Phadke M. Industrial Grease: Market analysis and Opportunities.NLGIIndia Chapter, In: Proceedings of the 16th Lubricating grease conference; 2014. Shashidhara YM, Jayaram SR. Vegetable oils as a potential cutting fluid-an evolution. Tribol Int 2010;43:1073–81. http://dx.doi.org/10.1016/j.triboint.2009.12.065. Silva J da. Biodegradable lubricants and their production via chemical catalysis. INTECH Open Access 2011. Singer I, Pollock H. Fundamentals of Friction: Mocroscopic and Microscopic Processes, Proceedings of a NATO Conference; 1992. Srivastava A, Sahai P. Vegetable oils as lube basestocks: a review. Afr J Biotechnol 2013;12:880–91. http://dx.doi.org/10.5897/AJB12.2823. Stachowiak Gwidon W, editor. Wear: materials, mechanisms and practice. John Wiley & Sons; 2006. Stempfel EM. Practical experience with highly biodegradable lubricants, especially hydraulic oils and lubricating greases. NLGI Spokesm 1998;62(1):8–23. Stgpina V. Lubricants and special fluids. Tribol Ser 1992;23:125–254. http:// dx.doi.org/10.1016/S0167-8922(08)70350-X. Subramaniam D, Murugesan A, Avinash A, Kumaravel A. Bio-diesel production and its engine characteristics-an expatiate view. Renew Sustain Energy Rev 2013;22:361–70. Thomas M, Chauhan D, Patel J, Panchal T. Analysis of biostimulants made by fermentation of Sargassum tenerimum seaweed. Int J Cur Tr Res 2013;2(1):405–7. Thomas M, Chauhan D, Patel J, Panchal T. Bioassay of biostimulants extracted from brown seaweed using various solvents and their comparison with extracts of terrestrial plants. Knowl Res 2015;2(1):1–3. Uosukainen E, Linko Y, Lämsä M, Tervakangas T, Linko P. Transesterification of trimethylolpropane and rapeseed oil methyl ester. J Am Oil Chem Soc 1998;75:1557–63. http://dx.doi.org/10.1007/s11746-998-0094-8. Vlček T, Petrović ZS. Optimization of the chemoenzymatic epoxidation of soybean oil. J Am Oil Chem Soc 2006;83:247–52. http://dx.doi.org/10.1007/s11746-0061200-4. Winer W, Peterson M. Wear Control Handb 1980. Yunus R, Fakhru’l-razi A, Ooi T, Iyuke S, Idris A. Development of Optimum Synthesis method for Transesterification of palm oil methyl esters and trimethylolpropane to environmentally acceptance palm. J Oil Palm Res 2003;15:35–41. Zaher FA, Nomany HM. Vegetable oils and lubricants. Grasas Aceites 1988;39:235–8.