Cardanol derivatives

Substituted phenols such as cresols, p-fcrf-butylphenol, / -phcnylphenol, resorcinol, and cardanol (derived from cashew nut shells) have also been used as precursors for phenolic resins. Alkylphenols with at least three carbons in the substituent lead to more hydrophobic phenolic resins that are compatible with many oils, natural resins, and rubbers.7 Such alkylphenolic resins are used as modifying and crosslinking agents for oil varnishes, as coatings and printing inks, and as antioxidants and stabilizers. Bisphenol-A (2,2-p-hydroxyphenylpropane),... 

Use of transition metal catalysts opens up previously unavailable mechanistic pathways. With hydrogen peroxide and catalytic amounts of methyl trioxorhe-nium (MTO), 2-methylnaphthalene can be converted to 2-methylnaphtha-l,4-qui-none (vitamin K3 or menadione) in 58 % yield and 86 % selectivity at 81 % conversion (Eq. 10) [43, 44]. Metalloporphyrin-catalyzed oxidation of 2-methylnaphtha-lene with KHSOs can also be used to prepare vitamin K3 [45]. The MTO-catalyzed process can also be applied to the synthesis of quinones from phenols [46, 47]. In particular, several benzoquinones of cardanol derivatives were prepared in this manner [48], The oxidation is thought to proceed through the formation of arene oxide intermediates [47]. 

Effects of various chemical treatments such as sodium hydroxide, isocyanate, permanganate, and peroxide on the tensile properties of sisal fiber-reinforced low-density polyethylene (LDPE) composites were investigated. Sodium hydroxide treated fiber composites showed better tensile properties than xmtreated composites, and the enhancement was attributed to their rough surface topography and increased aspect ratio. It was reported that long chain structured cardanol derivative of toluene diisocyanate (CTDIC) treatment reduces the hydrophilic nature of the sisal fiber resulting in improved compatibility and dispersion. It was also reported that peroxide treatment of fiber showed maximum interfacial interactions [33]. 

Most of the BPA-based epoxy resins are quite rigid and are based on petrochemicals. A quite different type of flexible epoxy resin is based on cardanol, derived from cashew nut shell liquid. Mono-, di- and multifunctional derivatives are possible. Mono- and difunctional low viscosity derivatives are used as modifiers and diluents, while complex di- and multifunctional epoxies are used in two-component ambient cure epoxy systems. They give the cross-linked matrix excellent flexibility, toughness and impact resistance. They possess very good water, chemical and corrosion resistance. 

Das, T.K., Das, D., Guru, B.N., Das, K.N., and Lenka, S. (1998) Polymers from Renewable Resources. XXVIII. Synthesis, Characterization, and Thermal Studies of Semi-Interpenetrating Polymer Networks Derived from Castor-Oil-Based Polyurethanes and Cardanol Derivatives, Polym.-Plast. Technol Eng., 37, 427-435... 

CF = cardanol-formaldehyde resin (cured) MCPAF = monocar-danyl phosphoric acid-formaldehyde resin (cured) BrCF = bromo derivative of CF BrMCPAF = bromoderivative of MCPAF PF = phenol-formaldehyde (cured) MPPAF = monophenyl phosphoric acid-formaldehyde (cured), BrPF = bromo derivative of PF BrMPPAF = bromoderivative of MPPAF PPF = phenol-formaldehyde resin phosphorylated (cured). 

The lower thermal stability of cardanol-formaldehyde resin and their derivatives were expected because of the presence of the libile side chain in the system. Although phenolics are superior in their properties, their bromo derivatives exhibit very low char yields. Oxidation of the char by a decomposition product is suspected. Evaluation of the LOI data with char yields individually for phosphorus and bromine suggests a positive interac-... 

Cardanol, a main component obtained by thermal treatment of cashew nut shell liquid (CNSL), is a phenol derivative having mainly the meta substituent of a C15 unsaturated hydrocarbon chain with one to three double bonds as the major. Since CNSL is nearly one-third of the total nut weight, a great amount of CNSL is obtained as byproducts from mechanical processes for the edible use of the cashew kernel. Only a small part of cardanol obtained in the production of cashew kernel is used in industrial fields, though it has various potential industrial utilizations such as resins, friction-lining materials, and surface coatings. Therefore, development of new applications for cardanol is very attractive. 

A new crosslinkable polymer was synthesized by the SBP-catalyzed polymerization of cardanol. When HRP was used as catalyst for the cardanol polymerization, the reaction took place in the presence of a redox mediator (phe-nothiazine derivative) to give the polymer. Fe-salen efficiently catalyzed the polymerization of cardanol in organic solvents (Scheme 29). " The polymerization proceeded in 1,4-dioxane to give the soluble polymer with molecular weight of several thousands in good yields. The curing of the polymer took place in the presence of cobalt naphthenate catalyst at room temperature or thermal treatment (150°C for 30 min) to form yellowish transparent films ( artificial urushi ... 

Figure 10.5 SEM images of self-assembled gel from cardanol glycolipids. (a) GLY-2 in cyclohexane (b) EtOH-HjO gel of the monoene derivative I (c) EtOH-H20 gel of GLY-2. Reprinted with permission from [71] (2006) American Chemical Society.

A new crosslinkable polymer was synthesized by the SBP-catalyzed polymerization of cardanol [103]. When HRP was used as catalyst for cardanol polymerization, the reaction took place in the presence of a redox mediator (phenothiazine derivative) to give the polymer [104]. 

Besides typical cardanol-like structure, Sleeper and Fenical have identified in 1977 navenone, an alkylphenol derivative as a component of trail pheromone of the mollusk Navanax inermis [27]. Another alkylpheno lie derivative, plakinidone, has beed isolated in 1991 from a Caribbean sponge Plakortis angulospiculatus [26]. In 1995 the carboxylic acid derivative of alkylphenol - elenic acid was isolated from the Indonesian sponge Plakinastrella [25]. The structures and formulas of known monohydric phenolic lipids are presented in Fig. (1). 

The properties of phenolic lipids have tended to be dominated by technological aspects and it is only comparatively recently that potential biological usefulness has come to the fore. For example, products derived from the Anacardiacae occidentale, notably cardanol obtained by semisynthesis through thermal decarboxylation were all directed to polymeric and technical applications and the vast industrial literature [246] contains only two references to insecticidal uses of chlorinated cardanol [247]. 

In recent years considerable attention has been given to the biodegradability of polyethoxylates and the role of their structure in this process. In consequence, there has been a move away from multi-branched alkyl side-chain in the starting alkylphenolic raw material towards more linear chains, a circumstance already adopted in the use of kerylbenzenes for the manufacture of alkylaryl sulphonates. Another practice adopted has been that of sulphation of the terminal hydroxyl group in the polyalkoxylate. Recent studies on a comparison of ethoxylates derived from the natural alkenylphenol, cardanol and from nonylphenol have indicated a considerable difference in biodegradability (ref. 24). 

By reaction of phosphorylated materials with aldehydes, amines or with isocyanates highly thermally stable products have been then produced. TGA studies have indicated their superior properties compared to conventional cardanol/formaldehyde resins of the novolac type. It was also found that a phosphorylated CNSL polymer had improved adhesive properties when compared with conventional CNSUformaldehyde resins (ref.248) and certain compounded products had wear, fade and frictional properties comparable to those of conventional PhOH/formaldehyde/copolymer brake Hnings (ref.249). The phosphorylated product from CNSL and its bromination derivative possessed good fire-retardant characteristics (ref. 250). Phosphorus derivatives of cardanol and of 3-pentadecylphenol have been studied by reaction with phosphorus oxychloride and its thio analogue (ref. 251). 

Various titanate compounds have been employed with cardanol probably forming di, tri and tetra-substituted derivatives which were found to be useful for viscosity reduction in organic/inorganic systems, as aqueous emulsifying agents and in the processing of calcium carbonate-filled PVC (ref.258). 

Although only cardol in CNSL has bifunctionality, attempts have been made to modify cardanol to the same effect. Thus reaction of (15 1)-cardanol with phenol in the presence of boron trifluoride afforded the 1,8-bis(hydroxyphenyl)pentadecane structure (ref. 261). Reaction then with a molar proportion of epichlorhydrin and polymerisation resulted in final products considered to be superior in properties to and cheaper than those derived from bisphenol A. The corresponding fully saturated cardbisphenol compound has been converted to a water soluble bis Mannich base by reaction with diethanolamine and formaldehyde (ref. 262) of value for cathodic electrodeposition. In another case of a related bis diethanolamine product, it was found necessary to react the hydroxyl groups with the monoisocyanate resulting from treatment of tolylenediisocyanate (TDI) with a molecular proportion of cardanol (ref. 263) in order to obtain a suitable binder for... 

The introduction of a vinyl group into the benzenoid ring of cardanol to impart triple functionality, consisting of the vinylic double bond, the hydroxyl group and the unsaturated side chain has been effected from the 6-formyl derivative of cardanol (ref. 264). 

Sodium anacardate is an excellent soap the water solubility of which has been used in a subsequent reaction (ref. 283). There has been, following work on the preparation of cardanol polyethoxylate (ref.284,285,286), by the reaction of cardanol with ethylene oxide at 180 C in the presence of a catalytic amount of potassium hydroxide, considerable interest in its ready biodegradability compared with that of ethoxylates derived from t-nonylphenol (ref.287). The individual ethoxy late oligomers were synthesised having values of n = 1 to 6 to identify the oligomers present in cardanol polyethoxylate and the ready biodegradation of cardanol and to a lesser extent that of of cardol polyethoxylates quantitatively established in comparison with that of t-nonylphenol polyethoxylate which remain comparatively undegraded. 

Drug analogues have previously been derived from saturated cardanol (ref. 2). In more recent work 3-pentadecylphenol and its 6-chloro derivative have been reacted with 2-chloropropionic acid and the derived methyl ester then converted to the hydrazide, reaction of which with cyanogen bromide afforded an aminooxadiazole while acetonylacetone gave a 2,5-dimethylpyrrole derivative (ref. 288). 

Ring-substituted derivatives have been widely examined. Thus, the selective o-formylation of mixed cardanol (R = was effected either through the... 

Reduction of isoanacardic aldehyde gave a methylol which could also be synthesised directly from cardanol together with formation of some of the 4,6-bis-methylol. The monomethylol compound isoanacardic alcohol was an effective solvent extractant for the borate anion (ref. 279, 293). The isomeric compound, anacardic alcohol (ref. 88) was similarly obtained from anacardic acid (ref. 180). This In conjunction with the teriary amine Aliquat 336 was highly effective for the solvent extraction of the borate anion (ref. 293). Both these substances were comparable in properties to the 2,6-bis(hydroxymethyl) derivatives of 4-t nonylphenol and to 4-t octyl-2-chloro-6-hydroxymethylphenol (ref. 294). 

Antioxidants derived from cardanol such as 2-pentadecyl-1,4-dihydroxybenzene have been referred to (ref. 2). Hindered phenols are generally more efficient and... 

Nayak, R.R. G. Ray B. Guru S. Lenka. Comparative studies of interpenetrating polymer networks derived from soybean oil-based polyurethane and cardanol m-aminophenol dye. Polym-Plast. Technol. 2004, 43, 261-272. 

They play a very important role in plants and also in plant-derived foods. They are one of the most important sources of bioactive compounds in the human diet [12], Accumulating clinical and epidemiological evidences have shown that phenolics might participate in prevention of various diseases associated with oxidative stress [13,14], Phenolic compounds could serve as a major determinant of antioxidant potential of foods because of their ability to donate a hydrogen atom or an electron in order to form stable radical intermediates. The major phenolics found in cashew are anacardic acids, cardanols, cardols, tocopherols, and other minor phenolic constituents. 

Cashew nut and its coproducts are rich sources of long-chain alkyl substituted saUcyhc add and resorcinol derivatives, namely anacardic acids, cardanols, cardols, and 2-methylcardols (Figure 10.1). The content of different alkyl substituted phenols, including anacardic adds, cardanols, and... 

Glycerol modified linseed oil based polyurethane and cardanol based dye Thermal stability of the blends was investigated using TGA, derivative Glycerol modified linseed oil based polyurethane and cardanol based dye Achary et al. 2012... 

C atalytic site of peroxidase is a heme, which is rapidly oxidized in its free form to hematin. p-Ethylphenol was polymerized using hematin as catalyst in an aqueous DMF (325). Iron-)VA -ethylenebis(salicyhdeneamine) (Fe-salen) also can be regarded as model complex of peroxidase. Fe-salen catalyzed an oxidative polymerization of various phenols such as 2,6-dimethylphenol, bisphenol A, cardanol, and urushiol analogues (251,293,326-329). The polymerization of 2,6-difluorophenol by Fe-salen produced a crystalline fluorinated PPO derivative (330). 

For instance cardanol, a phenol-based by-product of the cashew nut industry, is one of the common precursors used to obtain different types of epoxy bio-based resins. Cardanol is an industrial grade yellow oil obtained by vacuum distillation of cashew nut shell liquid (CNSL), the international name for the alkyl phenolic oil contained in the spongy mesocarp of the cashew nut shell from the cashew tree Anacardium occidentale L. CNSL derived from the most diffused roasted mechanical processes of the cashew industry represents nearly 25% of the total nut weight, and its production worldwide (Africa, Asia and South America being the main producer areas) is estimated to be about 300,000 tons per year (Calo et al., 2007). 

Anarcadic acid derivatives (in particular cardanol) and umshiols were transformed in several typical metal-catalyzed transformations (epoxidation, hydrogenation, and metathesis) [19] however, to date, hydroformylation has not been investigated, although a potential as plasticizers for PVC has been proven [20]. 

---