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Functionalization at the Double-Bond Region of Jojoba Oil. 3. Hydroxylic Derivatives Arnon Shani Department of Chemistry, Ben-Gurion Universiv of the Negev, Be'er-Sheva 84 120, Israel
The apolar and hydrophobic nature of jojoba oil has been altered to slightly more hydrophylic by epoxidation, hydrolysis, and alcoholysis at the double bonds, thus forming hydroxylic derivatives. Some inorganic esters, derived from SOCI,, POCI,, and (C,H,O),P, have been prepared. Exposure of the oil to direct sunlight in the presence of yielded some oxidized products. a photosensitizer (via '0,)
Introduction The high hydrophobicity of jojoba oil (I) precludes the miscibility with polar solvents. A small but significant change in this property can be achieved by introduction of highly hydrophilic groups, such as OH and its derivatives. These products might have some valuable properties in commercial chemicals where water or protic solvents are components together with oily chemicals, such as in cosmetics or detergents. As we have described previously (Shani 1981), the potentiality of the double-bond region of the liquid wax for functionalization, and a subsequent increase in polarity of the wax with two hydroxylic groups along the chain, has been found. The effect of four hydroxyl groups and their derivatives, built by hydroxylation of the double bonds, is assumed to be even greater. We describe here the preparation of several oxygenated products derived from the double bonds of jojoba oil. Experimental Section General. The crude product after each chemical transformation was used in the next step without further purification. The usual workup consisted of pouring the reaction mixture into H20,extraction with petroleum ether (60-80 "C), washing with saturated NaCl solution, and drying over anhydrous Na2S04. IR and 'H NMR spectra provided monitors for the chemical change occurring in each reaction. Purity was determined by 'H NMR (Shani, 1979; Shani and Horowitz, 1980). All NMR spectra gave the following: terminal CH3 as triplet at 6 0.92-0.94; an intense signal at 1.2-1.4 for all aliphatic hydrogens; a triplet at 2.20-2.26 for -CH,COO; and a triplet at 3.96-4.00 for -CH20C0. All other signals are described later and given in 6 units. Integration curves were consistent with the assignment of the different hydrogens. The NMR spectra were determined on a Varian XL-100 in CC14 or CDC1, solution with Me4Sias internal reference. The IR spectra were determined with a Perkin-Elmer Model 377 spectrometer. The samples were run neat or in CHC1, solution. Analytical thin-layer chromatography (TLC) plates were prepared with Silica Gel KGS-254. Microanalyses were performed in the Microanalytical Laboratory of the Applied Research Institute, BGU, Israel. Solvents. Petroleum ether (60-80 "C) was dried over CaC1, and distilled. Ether was dried over CaCl,, then over Na, and distilled. Chloroform, methanol, ethanol, 2propanol, t-BuOH, and toluene all were CP grade and used without drying. Thionyl chloride and phosphoryl chloride were freshly distilled before use. Jojoba Diepoxide (11) and trans-Jojoba Diepoxide (IIa). A solution of 20 g of jojoba oil (I) (0.034 mol) and 15 g of m-chloroperbenzoic acid (mCPBA) (85% pure, 0196-4321/83/1222-0121$01.50/0
Scheme I CH3(CH2)7 CH< H(C H d m e 0 (CH& C H=C H (C%) 7 C y
mcpY
C H 3 I C H 2 ) 7 C H C H ( C H 2 l m & ~ ~ " C HH(Cb)7CyH30.CMH2)7
Y
n,n&
d
k , C h C W H H H(Cr)m!O(cHz)n iH6H
H H(CH$,Ct$
SHIH
U
0.074 mol) in 100 mL of CHC13was stirred at room temperature for 24 h. The solid chlorobenzoic acid was filtered, the solvent was evaporated, and the residue was dissolved in petroleum ether (100 mL) and washed with 10% NaOH solution (2 X 20 mL) and then the usual workup to yield 17.3 g of jojoba diepoxide (11) (80%). IR 1 810 cm-'; 'H NMR 2.70 (4 H, OCHCH, bs). Under the same conditions 2.36 g of Ia (4 mmol) and 2 g of mCPBA (9.8 mmol) yielded 1.8 g of IIa (75%); IR 810 cm-'; 'H NMR 2.70 (1.4 H), cis-epoxide, bs), 2.50 (2.6 H, trans-epoxide, bs) (Scheme I). Jojobatetraol (111) and trans-Jojobatetraol (IIIa). (a) A solution of 17 g of I1 (0.027 mol) in 50 mL of petroleum ether and 50 mL 20% HC1 was refluxed for 20 h. The aqueous layer was separated and the organic phase was worked up to yield 13.2 g of jojobatetraol(II1) (74%); IR 3300-3400,1720 cm-'; 'H NMR 4.8-5.0 (4 H, OH, bs, disappeared with DzO), 3.75 (1.5 H, -CHOH, m), 3.50 (2 H, -CHOH, m); 'H NMR in C6H6: 3.64 (1.5 H, -CHOH, m), 3.45 (2 H, -CHOH, m) (Scheme I). (b) A mixture of 10 g of I (0.017 mol), 1.7 g of 30% H20z, 25 mL of glacial acetic acid, and 0.1 g of tetrabutylammonium bromide was heated to 80-85 "C for 45 h to yield hydroxylated and partly acetylated product in 65-70% conversion. When smaller amounts of H202were added in portions during the heating, the yield of the hydroxylated product I11 was 7 0 4 0 % (Scheme I). Under the same conditions as in (a) (except for 50 h of reflux) 0.4 g of IIa yielded 0.34 g of IIIa (80%). IR and NMR spectra were identical with those of 111. Alcoholysis of I1 with Different Alcohols To Yield IV, V, VI. 1. Methanol. A solution of 0.31 g of I1 (0.5 mmol) and 20 mg of p-toluenesulfonic acid (pTSA) in 10 mL of CH,OH was stirred at room temperature for 6 h. After addition of a saturated solution of NaHC03 and workup, 0.3 g of IV (80% purity) was isolated; IR 3300-3400, 1710 cm-'; 'H NMR 2.90-3.60 (6 H, -CH(OR)CH(OH)-, m), 3.35 (5 H, -OCH3, s), 2.60 (1.5 H, OH, disappeared in D20) (Scheme 11). A solution, as above, was heated at 50 "C for 10 h and yielded a mixture which was separated on preparative TLC (elution with 40% ether in petroleum ether) into 90 mg of VII; IR 3300-3400 (w) 1710 cm-l; 'H NMR 3.20-3.80 (2 0 1983 American Chemical Society
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Ind. Eng. Chem. Prod. Res. Dev., Vol. 22, No. 1, 1983
Table I. Solubility a of Jojoba Oil and Jojobatetraol (111) in Different Solvents solvent petroleum chlorosample ether ether form methanol water jojoba oil 950 560 1300 insoluble insoluble jojoba tetraol 600 650 600 1 7 insoluble a Amount of sample (mg) in 1 mL of solvent at room temperature. in sunlight for 14 days. Preparative TLC of 0.5 g of reaction mixture afforded 0.17 g of starting material and 0.10 g of more polar fraction (Rf0.2-0.3 in solution of 20% ether in petroleum ether) which exhibited similar IR and NMR spectra as XIV (Shani 1981). When methanol was used as solvent, methyl jojoboate (XV) (Shani et al., 1980) and jojobyl alcohol (XVI) were isolated as well as some hydroxylated product. 0 OH C H 3(C H 2 ) x C H C H=C H C H (CH 2
/I
OH CO (C H 2 ) I C HC H =C H C H (C H2 1, C H3
XI v
H, -CH(OR)CH(OH)- m), 3.55 (3 H, CH30C0,s), 3.30 (3 H, OCH,, 9); and 45 mg of VIII; IR 3330-3400,1710 (w) cm-'; 'H NMR 3.20-3.65 (2 H, -CH(OR)CH(OH)-, m), 3.50 (2 H, -CHzOH, t, J = 7 Hz), 3.30 (3 H, OCH,, S) (Scheme 11). 2. Ethanol. A solution of 0.31 g of I1 (0.5 mmol) and 20 mg of pTSA in 10 mL of ethanol was stirred at room temperature for 22 h to yield 0.28 g of V (80% pure, contained 20% of 11); IR 3300-3400,1710 cm-'; 'H NMR 2.95-3.70 (7.1 H, -CH(OR)CH(OH)-, and OCH2CH3,m), 3.15 (1.6 H, OH, bs, disappeared in D20). A solution as above heated at 70 OC for 5 h yielded a mixture of V, IX and X (Scheme 11). 3. 2-Propanol. A solution of 0.31 g of I1 (0.5 mmol) and 20 mg of pTSA in 10 mL of 2-propanol was heated at 70 "C for 6 h to yield 0.25 g of VI; IR 3300-3400,1710 cm-'; 'H NMR 3.10-3.80 (6 H, -CH(OR)CH(OH)- and OCH(CH,),, m) 3.20 (2 H, OH, bs, disappeared in D20). Similar results were obtained with 1Ia and the above-mentioned alcohols to yield IVa, Va, and VIa, respectively (Scheme 11).
Dijojobyl Phosphochloridate (XI).A solution of 0.66 g of I11 (1mmol) and 5 mL of POCl, in 20 mL of toluene was refluxed for 10 h to yield, after workup, 0.41 g of XI
-
x = 5, y = 7, 9, 11, 1 3 x = 7, y = 5, 7, 9, 11
C H ~ ( C H)7CH=C Z
xv
i
-
CH3(CH2)7CH=CHCH2)n
OH
XVI
Results and Discussion The epoxidation of jojoba oil has been described earlier (Wisniak, 1977). Acid hydrolysis of the diepoxide (11) yielded the tetrahydroxyjojoba oil (jojobatetraol, 111) (Scheme I). The same tetraol (ignoring stereochemical differences) was also obtained by direct hydroxylation of the wax with a mixture of H202/CH3COOH.This reaction could not be performed without a phase transfer catalyst, such as tetrabutylammonium bromide. In order to minimize the decomposition of HzOzin the heated reaction mixture, H202was added in several portions during the reaction. Heating continued for 40-50 h, leading to as much as a 70-80% yield. Under these conditions small percentage of acetate derivatives were also obtained. The solubility of jojobatetraol (111) in several solvents is compared to that of jojoba oil, as shown in Table I. There is a trend of lower solubility of the tetraol in several solvents, and poor solubility in methanol, while the wax itself is completely insoluble in methanol. These solubility differences are expected and demonstrate some increase in hydrophilicity of the hydroxylated wax. The same sequence of reactions (epoxidation and hydrolysis) was also performed on the isomerized jojoba, which contained as much as 65% of the trans double bonds in the chain (Shani, 1981). The ratio of the oxirane hydrogens in IIa fits well the isomeric composition of trans-jojoba (see Experimental Section). The tetraols, produced from jojoba oil (I) and trans-jojoba oil (Ia), show the same distribution of -CH(OH) in the NMR, namely two sets which are centered at 3.75 and 3.50 in the ratio of 3:4; in benzene solutions these are shifted upfield to 3.65 and 3.45. These bands are due to erythro and threo isomers. It has been shown (Kuranova and Balykina, 1978) that a difference of 0.15-0.2 ppm exists between the erythro and threo hydrogens in uic-dihydroxy fatty acids. Erythro hydrogens are usually at lower field (3.55-3.58) as compared to the threo isomer (3.33-3.39). In our case,
I
(50%); IR 1710 cm-'; 'H NMR 3.90-4.90 (4 H, OP(0)ClOCHCH, m). Cald for P: 7.5. Found, 8.8. Calcd for C1: 8.6. Found, 9.4 (Scheme 111). Dijojobyl Sulfite (XII).A solution of 0.66 g of I11 (1 "01) and 5 mL of SOClzin 20 mL of toluene was refluxed for 10 h to yield, after workup, 0.35 g of XI1 (47%); IR 1710 cm-'; 'H NMR 3.80-4.50 (4 H, OS(O)OCHCH,m). Calcd for S: 8.5%. Found: 6.8% (Scheme 111). Bis(diethyljojoby1) Phosphite (XIII).A solution of 0.66 g of I11 (1mmol) in 0.5 g of triethyl phosphite (TEP) (3 mmol) was refluxed for 20 h. Ethanol and an excess of TEP was distilled off at 65-70 O C / O . l mm to yield 0.75 g of XI11 (93%); IR 1710 cm-l; 'H NMR 3.90-4.20 (10 H, -CH,OCO, -CH,OP, OPOCHCH, m). Calcd for P: 7.7. Found: 7.0 (Scheme 111). Photooxidation of Jojoba Oil. A solution of 3 g of I and 60 mg of Rose bengal in 150 mL of t-BuOH was left
i;
H(CH2 ),COCH,
x = 5,z = 8, 10, 12, 14 x = 7,z = 6, 8, 10, 12
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Ind. Eng. Chem. Prod. Res. Dev. 1983, 22, 123-126
Table 11. R Values for Hydroxylic Derivatives of Jojoba Oi on TLC Plates % ether in petroleum ether compound 5 20 50 100 jojoba oil (I) 0.76 0.82 1.00 jojoba alcohol (XVI) 0.15 0.26 0.65 1.00 dihydroxyjojoba 0.03 0.12 0.59 0.88 oil (XIV) jojoba tetraol (111) 0.00 0.03 0.3-0.42 0.76-0.88 0.85 dimethoxy0.06-0.12 0.15 0.58 dihydroxyjojoba oil (IV) diethoxy0.06-0.120.18 0.82 0.92 dihydroxyjojoba oil (V) diisopropoxy0.06-0.12 0.24 0.88 0.94 dihydroxyjojoba oil (VI) bisjojobyl phospho- 0.00 0.12 long tailing chloridate (XI) bisjojobyl 0.3 0.65 0.76 sulfite (XII) bisjojobylethyl 0.03 0.05 0.23-0.3 0.5 phosphite (XIII) both cis- and trans-epoxides are opened in acid to identical tetraols. The mechanism is probably SN1type, which allows equilibration of the intermediates. The interesting point is that the threo-tetra01 isomer seems to predominate over the erythro isomer, whose conformations are less crowded and thus expected to be more stable. We rationalize this destabilization of the erythro, as compared to the threo, by the hydrophobic interactions which lead to the OH groups undergoing intramolecular hydrogen bonding, thus avoiding unfavorable interactions of the polar OH groups with the CH2 groups. This arrangement is more readily obtained in the threo isomer (i) than in the erythro (ii) isomer (see (i) and (ii), partial structure). Alcoholysis of the diepoxide (11) yielded the hydroxy ethers IV-VI (Scheme 11). The reaction was relatively fast in methanol and slowed down in ethanol and 2-propanol. While no heating was needed in methanol and ethanol (when the reaction mixtures were heated trans-esterifica-
I
I
H
OH
(i)
(ii)
tion took place), heating to 70 "C was needed in 2-propanol solution. The difference between methanol and ethanol was the length of the reaction, e.g., longer with ethanol (see Experimental Section). Some inorganic acid derivatives have been synthesized by reacting I11 with S0Cl2,POCl,, and (C2H50),P(Scheme 111). Formation of these cyclic esters proves the opening of the oxirane system to vicinal diol without rearrangement. These products, as well as the hydroxy and etheric derivatives, might be of some value as surfactants, in cosmetics, or additives which need some polar properties. Photooxidation of jojoba oil could be achieved by using a photosensitizer such as Rose bengal to produce lo2.The allylic alcohol (XIV) obtained by "ene reaction" is probably a mixture of isomers, but it behaved as a homogeneous polar product on TLC. The increase in the polarity of all products was exhibited by their reduced Rf on TLC plates as compared to jojoba oil, as shown in Table 11. Acknowledgment
The author wishes to thank Mrs. Dalia Gold for technical assistance. Literature Cited Kuranova, I. L.; Baiykina, L. V. Chem. Nat. Compd(Eng1. Trans/.)1978, 14, 247. Shani, A. J . Chem. Ecol. 1878, 5 , 557. Shani, A,; Lurie, P.; Wisniak, J. J . Am. Oil Chem. SOC. 1980, 57, 112. Shani, A.; Horowitz, E. J . Am. Oil Chem. SOC. 1880, 57, 161. Shani, A. J . Am. OilChem. Soc. 1881, 58,845. Wisniak, J. J . frog. Chem. Fats Other Lipids 1977, 75, 167.
Received for review March 2, 1982 Revised manuscript received August 2, 1982 Accepted August 15, 1982
Influence of Molecular Weight of Sodium Polyacrylate in Calcium Carbonate Aqueous Dispersions Jean-Marle Lamarche, Jacques Persello, and Alaln Folssy" Laboratolre d'Electrochimle des Solldes ERA 8 10, Unlversit6 de FranchsComt6, 25030 Besanpon Cedex, France
Sodium polyacrylatesdiffering in average molecular weight (700 to 20 000) and polydispersity index were studied
as dlspersing agents in calcium carbonate aqueous dispersions. Natural and synthetic CaCO, were used, but no difference was noticed between them. The maximum efficiency was obtained in rheological properties with a molecular weight between 2000 and 4000. This was shown to correspond to a higher and more specific adsorption of the molecules although no differences could be measured in electrokinetic potential. A strict correlation was found between adsorption isotherms, rheological properties, and electrophoretic mobility curves. The molecular weight distribution is found to have an important Influence on rheological properties.
Introduction
CaC03 is a very abundant mineral in the soil. Some veins can be used to provide filler materials for the paper, paint, and polymer industries if the ore quality is particularly high. Purity, whiteness, and the absence of quartz 0 1 96-432 1/83/ 1222-01 23$01.50/0
are the most important criteria to assess a vein quality. The development of CaC03 for use as a filler is due to the possibility of grinding it down to a fine powder. Stable slurries with relatively low viscosities can be made from this material if the necessary dispersing agents are used. 0 1983 American Chemical Society
