| 91.8% |
With Quinoline sulfate; at 75℃; for 3h;Catalytic behavior; |
In a 100 ml flask in three, respectively adding 0.05mol palmitic acid, 0.30mol methanol and 0.04mol quinolinemethyl bisulphate ion liquid, maintain the temperature of the reaction system in the 75 C left and right, a reflux condenser, thermostatic mixing 3h. The end of reaction, cooling, standstill, quinoline hydrosulfate ionic liquid separation by crystallization from the reaction system, the filter separating and recovering the ionic liquid. The pressure of the liquid phase to remove the unreacted excess methanol, into separatory funnel in the mixture, adding proper amount of saturated salt water washing, swing, to be after laminating, removed the lower layer of water, the upper layer of oily reservations, washed repeatedly 2-3 times, finally the obtained oily substance is product palmitic acid methyl ester, the yield is 91.8%. |
| 91.9% |
With C56H48O32S4; at 65℃; for 4h;Catalytic behavior; |
General procedure: Palmitic acid (0.6 g, 2.5 mmol) was dissolved in methanol (8.0 g, 250 mmol, 100 equivalent). Organocatalyst (Calix-A-SA, Calix-B-SA, or Calix-C-SA) (4 mol%) or concentrated sulfuric acid was added, and the mixture was heated at 65 C for 4 h. After the reaction, the mixture was cooled to room temperature and the organocatalyst was recovered by using a simple filtration method. The filtrate was neutralized with 10% sodium hydroxide in distilled water, extracted with ethyl acetate (3 X 10 mL) and the organic phase was washed with distilled water (10 mL) three times. The organic phase was dried over anhydrous sodium sulfate and the solvent was removed in vacuo to obtain methyl palmitate as a yellow liquid. FTIR (nu/cm1): 2916 (C-H sp3), 1743 (C=O), and 1332 (C-O ester). GC: single peak at retention time (tR) = 39.64 min. MS: 270 (M+), 239, 227, 199, 185, 171, 157, 143, 129, 115, 101, 87, 74 (base peak). The recovered calix-B-SA organocatalyst was re-used for the esterification of palmitic acid with methanol under similar conditions to afford methyl palmitate. |
| 88% |
With sulfuric acid; for 5h;Reflux; |
Following the reported procedures, to a solution of palmitic acid (5.57g, 20 mmol) in methanol (50 ml),H2SO4 (concentrated 98% w/w, 1.5 mL)was added dropwise and the mixture was refluxed for 5h. The mixture was cooled down and a saturated solution of NaHCO3 was added to pH = 7. Then, the resulting aqueous solution was washed with dichloromethane (3 x 20 mL) and the organic phase was dried, evaporated under vacuum and the residue was used in the next step without purification. Colourless oil (5.13g, 88% yield). IR, upsilonmax (cm-1 ):2915, 2843, 1739cm-1).1H-NMR, deltaH (ppm): 3.66 (s, 3H, COOCH3), 2.30 (t, 2H, CH2COO); 1.62 (m, 2H, CH2CH2COO), 1.28 (m, 24H, 12xCH2), 0.88 (t,J = 7.8 Hz, 3H, CH3). 13C-NMR, deltaC(ppm): 174.13 (CO), 51.4 (COOCH3), 34.2-22.8 (14xCH2), 14.1 (CH3). MS(DIP) m/z: 270(M+, 100%).HRMS required for C17H34O2requires: 270.2559; found: 270.2555. |
| 87% |
With cerium(III) trislaurylsulfonate monohydrate; In neat (no solvent); at 80℃; for 6h; |
General procedure: Carboxylic acid (1 mmol), alcohol (6 mmol) and 5 mol% catalyst were added to a 10 ml round-bottom flask with a reflux condenser.The reaction mixture was continuously stirred using a magnetic stirrer (800 rpm) at 80 C in an oil-bath for an appropriate time, andthe progress of reaction was monitored by TLC. At the end of reac-tion, the mixture was cooled to room temperature and poured intowater. Afterwards, the filtered cake was purified by chromatography on silica gel using petroleum ether/ethyl acetate (20:1) aseluent to give the pure product. |
| 77% |
With glycine ethyl ester hydrochloride; In cyclohexane; at 70℃; for 10h; |
Into a 500 mL three-necked flask equipped with a thermometer and a water separator, add 150 mL of methanol, 51.3 g (0.2 mol) of palmitic acid, stir and mix well, add 50 mL of cyclohexane and 2.52 g (0.02 mol) of glycine methyl ester hydrochloride, and heat up It was refluxed (at a temperature of 70 C) for 10 hours. After the temperature was lowered to room temperature, the solvent was recovered by concentration, and 50 mL of water was added to the concentrate, followed by extraction with 150 mL of ethyl acetate. The ethyl acetate layer was washed twice with 50% aqueous 5% sodium chloride, each 50 mL. After concentrating the ethyl acetate layer, 48.9 g of the crude product was obtained as a crude product. The product was collected under reduced pressure and collected at 154-158oC / 0.02 MPa to obtain 41.6 g of methyl palmitate as the final product. The final product was a pale yellow oily liquid, which became white after standing. Crystal. The purity by gas chromatography was 98.2%, and the reaction yield was 77.0%. The structure was confirmed by nuclear magnetic characterization. |
|
sulfuric acid; at 85℃; for 1.5h;Conversion of starting material; |
To provide a comparison basis for the functionalized mesoporous silicas, the esterification reaction was also performed with H2SO4 and two commercial acidic resins, Amberlyst-15 and Nafion. Shown in FIG. 3 are the results for reaction studies performed at 85 C. with a methanol to palmitic acid ratio of 20:1 by weight. The figure gives the palmitic acid concentration by weight as a function of reaction time. A catalyst concentration of 10 wt % was used for all of the catalysts except H2SO4, which was used at only 5 wt % concentration. As can be seen from the figure, the H2SO4 homogeneous catalyst is the most active with a conversion of more than 90% in less than 1.5 hr. The high activity of H2SO4 is consistent with results reported in the literature, where as low as 5 wt % loading of the cid was reported to be sufficient to esterify free fatty acids to levels of less than 0.5 wt % (B. Freedman et al., J. Amer. Oil Chem. Soc., 63, 1375 (1986). |
|
CDAB SO3H C16; for 3h;Conversion of starting material; |
Among the functionalized mesoporous silicas, SBA-15-SO3HP123 gave the highest catalytic activity and CDABSO3HC16 gave the least, with palmitic acid conversions of 85% and 55%, respectively, after 3 hr. The higher activity with SBA-15-SO3HP123 is consistent with the material having the largest number of active sites (1.44 meq/g sample) as well as the largest pore diameter (35 ?). This observation is consistent with that reported by W. D. Bossaert et al., J. Catal., 182 156 (1999) for the esterification of gylcerol with lauric acid (dodecanoic acid) using propylsulfonic acid functionalized mesoporous silica catalysts. |
|
SBA-15-SO3H P123; at 65 - 120℃; for 3h;Conversion of starting material; |
Among the functionalized mesoporous silicas, SBA-15-SO3HP123 gave the highest catalytic activity and CDABSO3HC16 gave the least, with palmitic acid conversions of 85% and 55%, respectively, after 3 hr. The higher activity with SBA-15-SO3HP123 is consistent with the material having the largest number of active sites (1.44 meq/g sample) as well as the largest pore diameter (35 ?). This observation is consistent with that reported by W. D. Bossaert et al., J. Catal., 182 156 (1999) for the esterification of gylcerol with lauric acid (dodecanoic acid) using propylsulfonic acid functionalized mesoporous silica catalysts. Determining the cause of the higher activity for the SBA-15-SO3HP123 catalyst comprises understanding of the relative importance of its higher active site concentration and its larger MPD, since both of these attributes could be contributing to the improved performance. To better evaluate these features, the reaction was performed at a range of temperatures from 65-120 C. These data were then used to calculate apparent activation energies for the catalysts. The apparent activation energies were calculated assuming a pseudo first-order reaction with respect to the palmitic acid given that methanol was present in excess and soybean oil was not significantly reacting. The linear regressions fit for the resulting values (0.95<R2<1) confirmed that the assumed first order kinetics were reasonable. |
|
amberlyst-15 resin; at 85℃; for 1.5h;Conversion of starting material; |
To provide a comparison basis for the functionalized mesoporous silicas, the esterification reaction was also performed with H2SO4 and two commercial acidic resins, Amberlyst-15 and Nafion. Shown in FIG. 3 are the results for reaction studies performed at 85 C. with a methanol to palmitic acid ratio of 20:1 by weight. The figure gives the palmitic acid concentration by weight as a function of reaction time. A catalyst concentration of 10 wt % was used for all of the catalysts except H2SO4, which was used at only 5 wt % concentration. As can be seen from the figure, the H2SO4 homogeneous catalyst is the most active with a conversion of more than 90% in less than 1.5 hr. The high activity of H2SO4 is consistent with results reported in the literature, where as low as 5 wt % loading of the cid was reported to be sufficient to esterify free fatty acids to levels of less than 0.5 wt % (B. Freedman et al., J. Amer. Oil Chem. Soc., 63, 1375 (1986).As seen in FIG. 3, Amberlyst-15 despite its high exchange capacity gave the least catalytic activity with a conversion of 40%, while the Nafion was intermediate relative to the mesoporous silica catalysts with a conversion of 70%. Amberlyst-15 is known to be an active catalyst in a number of esterification reactions and Nafion contains highly acidic sites, however, their low activity suggests that either their catalytic sites are not accessible or under the given reaction conditions they are not sufficiently reactive. |
|
nafion resin; at 85℃; for 1.5h;Conversion of starting material; |
To provide a comparison basis for the functionalized mesoporous silicas, the esterification reaction was also performed with H2SO4 and two commercial acidic resins, Amberlyst-15 and Nafion. Shown in FIG. 3 are the results for reaction studies performed at 85 C. with a methanol to palmitic acid ratio of 20:1 by weight. The figure gives the palmitic acid concentration by weight as a function of reaction time. A catalyst concentration of 10 wt % was used for all of the catalysts except H2SO4, which was used at only 5 wt % concentration. As can be seen from the figure, the H2SO4 homogeneous catalyst is the most active with a conversion of more than 90% in less than 1.5 hr. The high activity of H2SO4 is consistent with results reported in the literature, where as low as 5 wt % loading of the cid was reported to be sufficient to esterify free fatty acids to levels of less than 0.5 wt % (B. Freedman et al., J. Amer. Oil Chem. Soc., 63, 1375 (1986).As seen in FIG. 3, Amberlyst-15 despite its high exchange capacity gave the least catalytic activity with a conversion of 40%, while the Nafion was intermediate relative to the mesoporous silica catalysts with a conversion of 70%. Amberlyst-15 is known to be an active catalyst in a number of esterification reactions and Nafion contains highly acidic sites, however, their low activity suggests that either their catalytic sites are not accessible or under the given reaction conditions they are not sufficiently reactive. |
|
sulfuric acid; sodium dodecyl-sulfate; In water; at 70 - 72℃; for 6h;Product distribution / selectivity; |
EXAMPLE 54; This example demonstrates the behavior of a water soluble alcohol, methanol, in the esterification reaction of the present invention. A reactor was charged with palmitic acid (1.05 parts), methyl alcohol (3.95 parts), and sodium lauryl sulphate (0.25 parts). After warming under agitation to 70-72 C., sulphuric acid (10% aqueous solution, 0.47 parts) was added and the mixing and temperature maintained for six hours. A sample of the mixture reveals that 99 mole % of the palmitic acid was converted to methyl palmitate. |
| 75 - 94.0%Chromat. |
at 270 - 400℃; under 127513 - 562556 Torr; for 0.0333333 - 0.333333h;Product distribution / selectivity; |
(Esterification Reaction of Fatty Acid) An esterification reaction of a fatty acid and methanol was conducted using, as a raw material, palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid (all manufactured by Nacalai Tesque) commercially available as a reagent, and under conditions of volume ratio, temperature, pressure and reaction time shown in Table 5. For the esterification reaction of a fatty acid and methanol, a fatty acid and methanol were filled at a mole ratio of 1:42 in a Inconel-625 reaction tube having a content volume of 5 ml, and the same procedure as in the methyl-esterification reaction in Example 1 was conducted. After removal of unreacted methanol and produced water in the same manner as in Example 1, the reaction product was dissolved in fresh methanol and HPLC analysis was conducted. From the HPLC analysis result, the conversion from a fatty acid into a fatty acid alkyl ester (=yield of methyl ester) was obtained. The results are shown in Table 5 together with reaction conditions. TABLE 5 Reac- Tem- tion Fatty Fatty acid (ml)/ perature Pressure time Yield Example acid methanol (ml) ( C.) (Mpa) (min) (%) Example 3-1C16-0 0.91:4.09 270 17 20 90 Example 3-2C16-0 0.91:4.09 300 24 7 88 Example 3-3C16-0 0.91:4.09 350 43 4 75 ComparativeC16-0 0.91:4.09 400 75 2 92 example 3-1 Example 3-4C18-0 0.91:4.09 270 17 20 98 Example 3-5C18-0 0.91:4.09 300 24 7 98 Example 3-6C18-0 0.91:4.09 350 43 4 100 ComparativeC18-0 0.91:4.09 400 75 2 100 example 3-2 Example 3-7C18-1 0.91:4.09 270 17 20 98 Example 3-8C18-1 0.91:4.09 300 24 7 98 Example 3-9C18-1 0.91:4.09 350 43 4 98 ComparativeC18-1 0.91:4.09 400 75 2 94 example 3-3 Example 3-10C18-2 0.91:4.09 270 17 20 98 Example 3-11C18-2 0.91:4.09 300 24 7 98 Example 3-12C18-2 0.91:4.09 350 43 4 87 ComparativeC18-2 0.91:4.09 400 75 2 80 example 3-4 Example 3-13C18-3 0.91:4.09 270 17 20 99 Example 3-14C18-3 0.91:4.09 300 24 7 96 Example 3-15C18-3 0.91:4.09 350 43 4 93 ComparativeC18-3 0.91:4.09 400 75 2 61 example 3-5 C16-0: palmitic acid, C18-0: stearic acid, C18-1: oleic acid, C18-2: linoleic acid, C18-3: linolenic acid An esterification reaction of a fatty acid and alcohol or a transesterification of rapeseed oil and alcohol was conducted using, as a raw material, fats and oils and alcohols shown in Table 7, under conditions of mole ratio, temperature, pressure and reaction time shown in Table 7. Since about 98.5% of rapeseed oil is composed of a tri-glyceride, the reaction from rapeseed oil can be judged to be a transesterification. The reaction product was subjected to HPLC analysis in the same manner as in Example 1, from the HPLC analysis result, conversion into a fatty acid alkyl ester from a fatty acid or rapeseed oil (=yield of alkyl ester) was obtained. The results are shown in Table 7 together with the reaction conditions. TABLE 7 Alcohol/fats and oils Temperature Pressure Reaction Example (mole ratio) Fats and oils Alcohol ( C.) (Mpa) time (min) Yield (%) Example 42/1C18-3 Methanol 300 20 8 96.2 5-1 Example 42/1C18-2 300 20 8 95.1 5-2 Example 42/1C18-1 300 20 8 95.8 5-3 Example 42/1C18-0 300 20 8 94.7 5-4 Example 42/1C16-0 300 20 8 94.0 5-5 Example 42/1 Rapeseed 300 20 15 98.0 5-6 oil Example 42/1 Rapeseed 350 43 4 98.0 5-7 oil Example 42/1C18-3 Ethanol 300 15 12 94.6 5-8 Example 42/1C18-2 300 15 14 97.4 5-9 Example 42/1C18-1 300 15 14 95.9 5-10 Example 42/1C18-0 300 15 15 91.2 5-11 Example 42/1C16-0 300 15 14 91.7 5-12 Example 42/1 Rapeseed 300 15 45 96.7 5-13 oil Example 42/1 Rapeseed 350 25 10 97.1 5-14 oil Example 42/1C18-3 1-propanol 300 10 15 97.0 5-15 Example 42/1C18-2 300 10 14 92.7 5-16 Example 42/1C18-1 300 10 14 92.3 5-17 Example 42/1C18-0 300 10 14 89.6 5-18 Example 42/1C16-0 300 10 14 90.1 5-19 Example 42/1 Rapeseed 300 10 45 96.1 5-20 oil Example 42/1 Rapeseed 350 23 14 98.8 5-21 oil Example 42/1C18-3 1-butonal 300 9 15 97.3 5-22 Example 42/1C18-2 300 9 14 92.4 5-23 Example 42/1C18-1 300 9 14 86.1 5-24 Example 42/1C18-0 300 9 14 82.5 5-25 Example 42/1C16-0 300 9 14 81.1 5-26 Example 42/1 Rapeseed 300 9 45 87.1 5-27 oil Example 42/1 Rapeseed 350 23 14 95.3 5-28 oil Example 42/1 Rapeseed 1-octanol 300 6 45 68.7 5-29 oil Example 42/1 Rapeseed 350 19 20 90.7 5-30 oil C16-0: palmitic acid, C18-0: stearic acid, C18-1: oleic acid, C18-2: linoleic acid, C18-3: linolenic acid |
|
sulfonated peanut hull biocar; at 58℃; for 1h;Product distribution / selectivity; |
A known amount of catalyst (typically 0.2 g) was charged into a vial (5 mL total volume) with a known initial volume of palmitic (C16-saturated FFA) or stearic (C18-saturated, both at 200 ppm) and methanol (4 mL, excess methanol). The mixture was then heated at 55-60 C. and sub-samples taken as function of time to determine the formation of methyl esters. Control reactions consisted of the untreated char (negative control) or use of HCl (positive control). The liquid sub-samples were analyzed and quantified using a GC/FID or GC/MS and hexadecane was used as an internal standard to determine the concentration of methyl esters formed. Fractional removal or % conversion of palmitic or stearic acid were based on the defined initial concentrations of the FFAs (maximum theoretical amount of methyl ester that could form) and the concentration of the methyl esters of the FFAs that formed during the catalytic reaction, thus % X or Conversion=[Cfinal(FFA-ME)]/Cinitial(FFA-ME)×100, where C is concentration, FFA is free fatty acid, and FFA-ME is fatty acid methyl ester. studies clearly indicated that sulfonation of the chars was required for catalytic activity and esterification did not take place without the catalysts. Controls consisted of a blank (methanol plus palmitic or stearic acid) and non-sulfonated chars (char plus palmitic or stearic acid and methanol). Reactions (0.10 g peanut hull char, 5 mL methanol, and 200 ppm of palmitic or stearic acid) conducted at 50 C. for 4 hours (data not shown) or 58 C. for 1 h (FIG. 21) indicated no formation of methyl esters, contrary to positive controls using HCl (1 drop 38% HNO3) under identical conditions, which resulted in 100% conversion of the fatty acids to methyl esters (data not shown). |
|
With 25,26,27,28-terahydroxycalix[4]arene-5,11,7,23-tetrasulfonic acid; for 4h;Reflux; |
General procedure: General procedure for the synthesis of compounds (6a-p); organic acid (0.40 mmol.), and catalyst (0.0005 mmol.) was combined with 20 mL ethanol in a 50 mL round bottomed flask equipped with a stir bar. Reaction was allowed to stir at reflux temperature for the appropriate amount of time (4 h). After completion of reaction, the reaction mixture was concentrated in vacuum to give a crude product which was analyzed by 1H NMR and GC-MS. |
| 93%Chromat. |
With trimethylcyclohexylammonium methanesulfonate; toluene-4-sulfonic acid; at 60℃; for 2h; |
General procedure: Equimolar amounts of quaternary ammonium salt (1.5 mmol) and p-toluenesulfonic acid monohydrate (Sigma-Aldrich, 98,5+% used as received) were mixed in a screw-capped 3 ml vial. The mixture was magnetically stirred and heated to 60 C until a clear colourless liquid was obtained (about 10 min). DES was used right after its preparation. Equimolar amounts (4.5 mmol) of acid and alcohol were added, and the resulting mixture, was heated to 60 C (or 80 C if specified) and magnetically stirred for the specified amount of time. Initially the reaction mixture is homogeneous and fluid, and then a heterogeneous system formed as reaction proceeded, due to insolubility of the esters produced in the DES. For the g.c. analysis further elaboration was as follows. At the end of the reaction, tbutylbenzene was added, as the internal standard, to the mixture, which was then extracted with diethyl ether. Organic layer was washed with NaHCO3, dried over Na2SO4 and analyzed by g.c. |
|
With C5H14NO(1+)*2H(1+)*O40PW12(3-); at 65℃; for 0.833333h;Microwave irradiation;Catalytic behavior; |
Esterification reactions were carried out in the presence of ChH2PW at different reaction conditions. This reaction mixture was then irradiated by microwave (A 2450 MHz microwave generator) under reflux (65 C) for the specified reaction time. After the esterification reaction completed, the upper layer were esters and the excess alcohol and the lower layer was the catalyst, which was recovered by decantation and washing with methanol and removing water under a vacuum at 60 C for further use. The mixture was concentrated using a rotary evaporator to remove the excess alcohol. The conversion of free fatty acid into ester was calculated by measuring the acid value of the product and the yield of ester was detected by gas chromatography (GC). |
|
at 40℃; for 6h;Sealed tube; |
Reaction was carried out in a glass flask reactor where 1 gof palmitic acid (3.8 mmol) and 15 cm3of methanol were added(molar ratio 1/97) [25]. The flask reactor was sealed to avoidevaporation and placed on a shaker at constant stirring speed with a thermostatically controlled bath at different temperatures(between 30 and 60C). Once the palmitic acid was dissolved,the catalyst was added. The amount of catalyst varied from 3 to80 mg for unsupported HPA studies and between 50 and 200 mgfor supported HPA on ACF. These experimental conditions weremaintained during 6 h, although additional experiments were per-formed up to 24 h. In addition, the used catalysts were reused insuccessive cycles.To determine the progress of the reaction, three differ-ent aliquots were analyzed at 1, 3 and 6 h (also at 24 h forlonger duration experiments). Reaction yield was determinedby titration using a NaOH 0.1 M (Aldrich) standard pattern.Moreover, the nature of the reaction products was analyzedby gas chromatography coupled to mass spectrometry (Shi-madzu, GCMS QP5050A with a polydimethylsiloxane column CBPIPONA-M50-042 from Shimadzu, 100 mm × 0.25 mm × 0.5 mm),so methyl palmitate was confirmed as the only reactionproduct. |
|
With hexanoic acid; at 60℃;Sealed tube;Catalytic behavior; |
Reactions were performed using a Radleys Carousel ReactorStation at atmospheric pressure. 12.5 cm3(300 mmol) or methanol,10 mmol of hexanoic (C6) or palmitic (C16) acid, and 2.5 mmolof hexylether (as an internal standard) were added to a sealedglass reactor tube under stirring at 60C. 0.05 g of sulfonic acidcatalyst was subsequently introduced, and aliquots of the reac-tion mixture periodically withdrawn and filtered and diluted withdichloromethane for analysis on a Varian 450-GC. Analysis of reac-tion products from palmitic acid esterification employed a 1079programmable, direct on-column injector and Phenomenex ZB-1HT Inferno 15 m × 0.53 mm × 0.15 m capillary column. Initialrates were calculated over the first two hours of reaction, whereinsimilar acid conversions of 5-10% were obtained, so as to be ina regime where the concentrations of reactively-formed waterwere comparable. Product yields determined from response factorsfor methyl palmitate, with mass balances determined to be >98%.Errors in TOF were calculated from the variance in the line of bestfit to initial rate plots, and repeat measurements of initial rate andacid site titrations on selected catalysts, from which a compositeerror of ±5% was determined. |
| 90.7%Spectr. |
With mesoporous 1-butyl-3-methylimidazolium supported sulfated zirconia nanocrystal; at 59.84℃; for 8h;Inert atmosphere; Green chemistry; |
General procedure: 2.4. Esterifiaction of long chain fatty acids and transesterificationreactionsFor each of the catalytic reaction 1 mmol of the reactant fattyacid was dissolved in 0.96 g methanol taken in a 50 ml round bottomflask. Then 80 mg of M-IL-SZO-1C catalyst was added into the RBflask. The reaction mixture was refluxed at 333 K for 8 h under thenitrogen atmosphere. To study the progress of the reaction, thereaction mixtures were collected at different time intervals and theprogress of the reactions were monitored by TLC. |
|
With SBA-15 silica functionalized with 15 molar percentage of phenolsulfonic acid (15PholSO3H-SBA-15-p); for 12h;Reflux;Catalytic behavior; |
Example 7 PholSO3H-SBA-15 Catalyzed Esterification of Palmitic AcidThe phenolsulfonic acid-functionalized SBA-15 (15PholSO3H-SBA-15-p) was used as the solid acid catalyst in the liquid phase esterification of palmitic acid (PA) with methanol (MeOH) and iso-propanol (iPrOH) to form methylpalmitate and iso-propylpalmitate as the products, respectively. The reactions were carried out at the reflux temperatures of the alcohols. The esters were found to be the only products in the present reaction condition based on the GC and GC-MS analyses. (0084) FIG. 7A and FIG. 7B show the conversions of palmitic acid in the esterification of palmitic acid with MeOH and iPrOH, respectively. In FIGS. 7A and 7B, the conversions of palmitic acid are shown as a function of reaction period over 15PholSO3H-SBA-15-p and commercially available Amberlyst-15 resin. It is clearly shown that the conversions of palmitic acid over 15PholSO3H-SBA-15-p increase much faster than those over Amberlyst-15 resin. After 12 hours reaction, significantly larger amounts of esters are obtained over 15PholSO3H-SBA-15-p than Amberlyst-15 resin. (0085) Table 5 demonstrates the recyclability of the 15PholSO3H-SBA-15-p catalyst. The used catalyst was regenerated by simple filtration and drying at 100 C. The catalytic activities of 15PholSO3H-SBA-15-p were well retained in comparison to that of the fresh catalyst after recycling for two times. |
|
With pillared HMCM-36 zeolite; at 70℃; for 24h;Kinetics; Catalytic behavior; |
Esterification of palmitic acid Esterificiation reactions were performed in a stirred batch reac-tor with samples withdrawn periodically for analysis using aShimadzu GC17A Gas Chromatograph fitted with a DB1 capillarycolumn (film thickness 0.25 mm, id 0.32 mm, length 30 m). Reac-tions were performed at 70C using 0.05 g of catalyst, 5 mmol ofpalmitic acid, 0.0025 mol (0.587 mL) hexyl ether as internal stan-dard, and 0.3036 mol (12.5 mL) methanol. Reaction profiles were followed for a period of 6 h and continued for 24 h to assess limiting conversions |
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