PROCESS FOR PREPARING GLYCEROL ESTERS
The present invention relates to a process. In particular, the present invention relates to a process for preparing a compound which may act inter alia as a plasticiser and to a compound prepared by that process.
The manufacturing properties of thermoplastic polymers, for example the extruding properties of such polymers, is often modified/enhanced by the addition of plasticisers thereto. As acknowledged in the prior art, such as in US-A-4426477, there is a tendency toward avoiding the commonly used plasticisers such as dioctyl adipate (DOA) and phthalate plasticisers such as dioctyl phthalate (DOP). The safety of these plasticisers has been called into question, particularly in certain applications.
US-A-4426477 discloses plasticisers based on glycerol esters. The plasticisers consist of compounds prepared by the acylation of glycerol. The compounds comprises triesters, wherein approximately two of the acyls have two carbons and the remaining one acyl has from 10 to 14 carbons. The compounds of US-A-4426477 provide a plasticising effect. However, in certain applications the plasticisers have a volatility such that they may migrate out of the thermoplastic polymer in which they are incorporated, such as PVC.
Our earlier application published as WO 01/14466 teaches a thermoplastic polymer composition containing a compound having the formula
wherein R
1, R
2 and R
3 are independently selected from an acyl group or a hydrogen atom, wherein at least one of R
1, R
2 and R
3 is an acyl group (a short acyl group) having from 2 to 6 carbon atoms, and wherein at least one of R
1, R
2 and R
3 is a branched chain acyl group (a long acyl group) consisting of a saturated chain having 10 to 20 carbon atoms and a hydrophilic branch group.
WO 01/14466 discloses a process for the production of acylated monoglyceride of hydrogenated castor oil, which includes acylation of the hydrogenated castor oil with an
acylation agent such as a short chain fatty acid anhydride followed by an interesterification of the acylated hydrogenated castor oil with a triacyl glycerol of a short chain fatty acid. The excess short chain tri acyl glycerol is removed and the product, an acylated monoglyceride of hydrogenated castor oil, is recovered. This process has some drawbacks due to the high temperature of about 2500C involved during the interesterification of the acylated hydrogenated castor oil with the short chain triacyl glycerol. The high temperature can causes pyrolytic elimination of the short acyl group on the hydroxy fatty acid, leaving an unsaturated fatty acid, which reduces the stability of the product when incorporated into a thermoplastic polymer such as PVC. The present invention alleviates problems of the prior art.
Aspects of the invention are defined in the appended claims.
In one aspect the present invention provides a process for the preparation of a compound of the formula
wherein one of R
1, R
2 and R
3 is selected from groups R
6, R
7 and R
8; wherein two of R
1, R
2 and R
3 are independently selected from groups R
9, R
10 and R
11; the process comprising the step of interesterifying in the presence of an enzyme catalyst (a) a triglyceride compound of the formula
wherein each of R
6, R
7 and R
8 is independently selected from branched groups of the
formula
q is from 0 to 3, wherein each R
5 is independently selected from -OH and -0-C(O)-R
4; wherein n is from 10 to 21 and m is selected from 2n-q, 2n-2-q, 2n-4-q, and 2n-6-q, wherein each R
4 is independently selected from alkyl, alkenyl and alkynyl groups containing z carbon atoms, wherein z is from 1 to 21 , and
(b) a triglyceride compound of the formula
wherein each of R
9, Ri
0 and Rn is independently selected from alkyl, alkenyl or alkynyl groups containing x carbon atoms, wherein each x is independently selected from 1 to 1 1 .
SOME ADVANTAGES
The present process overcomes the high temperature problems of WO01/14466. Moreover, the present process allows for the possibility of using different acyl groups on the hydrophilic branch group and on the glycerol backbone. This is possible in the processes described in the prior art.
For ease of reference, these and further aspects of the present invention are now discussed under appropriate section headings. However, the teachings under each section are not necessarily limited to each particular section.
PREFERRED ASPECTS
Enzyme
The enzyme for use in the process of the present may be any suitable enzyme capable of performing the required interesterification between the triglyceride compound of the formula
and the triglyceride compound of the formula
In one preferred aspect the enzyme is a lipase or protease.
Preferably the enzyme is a lipase and in particular the enzyme or the lipase is a 1 ,3 specific lipase. A preferred enzyme is Lipozyme TL IM available from Novozyme A/S, Denmark.
In one preferred aspect the enzyme is immobilised. The enzyme may be any suitable method, such as those described in EP-A-0407959 and include carrier bonding, crosslinking and inclusion. As an immobilizing carrier one may use those mentioned in EP-A-0407959, specifically, those inorganic materials such as active carbon, porous glass, acidic white clay, bleached white clay, kaolinite, alumina, silica gel, bentonite,
hydroxyapatite, potassium phosphate and other metal oxides, natural polymeric compounds such as starch and gluten, synthetic polymeric materials such as polyethylene, polypropylen, phenol-formalin resin, acrylic resin, anionic exchange resin and cationic exchange resin. In particular, synthetic polymeric material having porosity as the physical form, for example, porous polyethylene, porous polypropylene, porous phenol formalin resin, porous acrylic resin. Various immobilizing carriers other than above may be used.
R1 to R3
As discussed herein one of R1, R2 and R3 is selected from groups R6, R7 and R8; and the other two of R1, R2 and R3 are independently selected from groups R9, R10 and Rn;. It will be understood by one skilled in the art and from the nature of an interesterification reaction that groups R1, R2 and R3 are provided by 'donation' of groups from one triglyceride ester to another. Thus the compound prepare by the process of the present invention has its glycerol backbone provided by the triglyceride compounds provided from reaction in the process and the groups R1, R2 and R3 are provided in part from one triglyceride and in part from the other triglyceride.
In one aspect R1 is selected from groups R6, R7 and R8; and R2 and R3 are independently selected from groups R9, R10 and R11.
In one aspect R2 is selected from groups R6, R7 and R8; and R1 and R3 are independently selected from groups R9, R10 and R11.
In one aspect R3 is selected from groups R6, R7 and R8; and R1 and R2 are independently selected from groups R9, R10 and R11.
R6 to R8
As discussed herein each of R6, R7 and R8 is independently selected from branched
groups of the formula
q is from 0 to 3, wherein each R
5 is
independently selected from -OH and -0-C(O)-R
4; wherein n is from 10 to 21 and m is selected from 2n-q, 2n-2-q, 2n-4-q, and 2n-6-q, wherein each R
4 is independently selected from alkyl, alkenyl and alkynyl groups containing z carbon atoms, wherein z is from 1 to 21.
It will be appreciated that q may be any of 0, 1, 2 or 3. In one aspect q is preferably 0. In one aspect q is preferably 1. In one aspect q is preferably 2. In one aspect q is preferably 3.
Integer q determines the number of R5 groups attached to the CnHm moiety. It will be readily understood that the number of H i.e. the value of m will in some degree be determined by the number of R5 groups i.e. the value of q.
R5
As discussed herein each R5 is independently selected from -OH and -0-C(O)-R4; wherein n is from 10 to 21 and m is selected from 2n-q, 2n-2-q, 2n-4-q, and 2n-6-q, wherein each R4 is independently selected from alkyl, alkenyl and alkynyl groups containing z carbon atoms, wherein z is from 1 to 21.
In one aspect at least one R5 is-OH.
In one aspect each R5 is-OH.
In one aspect at least one R5 Js-O-C(O)-R4; wherein n is from 10 to 21 and m is selected from 2n-q, 2n-2-q, 2n-4-q, and 2n-6-q, wherein each R4 is independently selected from alkyl, alkenyl and alkynyl groups containing z carbon atoms, wherein z is from 1 to 21.
In one aspect each R5 is selected from -0-C(O)-R4; wherein n is from 10 to 21 and m is selected from 2n-q, 2n-2-q, 2n-4-q, and 2n-6-q, wherein each R4 is independently selected from alkyl, alkenyl and alkynyl groups containing z carbon atoms, wherein z is from 1 to 21.
In one aspect at least one R5 is-OH and at least one R5 Js-O-C(O)-R4; wherein n is from 10 to 21 and m is selected from 2n-q, 2n-2-q, 2n-4-q, and 2n-6-q, wherein each R4 is independently selected from alkyl, alkenyl and alkynyl groups containing z carbon atoms, wherein z is from 1 to 21.
R4
Each R4 is independently selected from alkyl, alkenyl and alkynyl groups containing z carbon atoms, wherein z is from 1 to 21.
In one aspect at least one R4 is independently selected from alkyl groups containing z carbon atoms, wherein z is from 1 to 21. In one aspect each R4 is independently selected from alkyl groups containing z carbon atoms, wherein z is from 1 to 21.
In one aspect at least one R4 is independently selected from alkenyl groups containing z carbon atoms, wherein z is from 1 to 21. In one aspect each R4 is independently selected from alkenyl groups containing z carbon atoms, wherein z is from 1 to 21.
In one aspect at least one R4 is independently selected from alkynyl groups containing z carbon atoms, wherein z is from 1 to 21. In one aspect each R4 is independently selected from alkynyl groups containing z carbon atoms, wherein z is from 1 to 21.
In each aspect of the invention z is from 1 to 21. In one preferred aspect z is from 7 to 17. In one preferred aspect z is from 7 to 15. In one preferred aspect z is from 7 to 13. In one preferred aspect z is from 9 to 13. In one preferred aspect z is 11.
The or each z or at least one z may be different to at least one x. In one aspect the or each z is different to at least one x.
The or each z or at least one z may be different to each x. In one aspect the or each z is different to each x.
In one aspect the or each z or at least one z is equal to each. In one aspect the or each z is equal to each x.
n
As discussed herein n is from 10 to 21. Preferably n is from 15 to 21 , for example n may be from 15 to 19. Preferably n is 17.
m
The integer m is selected from 2n-q, 2n-2-q, 2n-4-q, and 2n-6-q. It will be appreciated that the value of m will depend on the number of 'spare' valencies on the n number of carbons. The group CnHm may be saturated (2n-q), contain one degree of unsaturation (2n-2-q), contain two degrees of unsaturation (2n-4-q), or contain three degrees of unsaturation (2n-6-q). When the group CnHm contains degrees of unsaturation this may be in the form of C=C bonds, C≡C bonds or a combination thereof.
As discussed herein each of R9, Ri0 and Rn is independently selected from alkyl, alkenyl or alkynyl groups containing x carbon atoms, wherein each x is independently selected from 1 to 11.
In one aspect at least one of R9, R10 and R11 is independently selected from alkyl groups containing x carbon atoms, wherein each x is independently selected from 1 to 11. In one aspect each of R9, R10 and Rn is independently selected from alkyl groups containing x carbon atoms, wherein each x is independently selected from 1 to 11.
In one aspect at least one of R9, R10 and R11 is independently selected from alkenyl groups containing x carbon atoms, wherein each x is independently selected from 1 to 11. In one aspect each of R9, R10 and R11 is independently selected from alkenyl groups containing x carbon atoms, wherein each x is independently selected from 1 to 11.
In one aspect at least one of R9, R10 and R11 is independently selected from alkynyl
groups containing x carbon atoms, wherein each x is independently selected from 1 to 11.. In one aspect each of R9, R10 and Rn is independently selected from alkynyl groups containing x carbon atoms, wherein each x is independently selected from 1 to 11.
X
Each x is independently selected from 1 to 11.
In one preferred aspect at least one x is independently selected from 1 to 5. Preferably each x is independently selected from 1 to 5.
In one preferred aspect at least one x is independently selected from 1 to 3. Preferably each x is independently selected from 1 to 3.
In one preferred aspect at least one x is 1. Preferably each x is 1.
In one aspect each x is the same.
P ref e r red As pects
In one highly preferred aspect of the present invention each x is 1 and z is 11.
In one highly preferred aspect of the present invention each x is 1 , n is 17 and z is 1.
In one highly preferred aspect of the present invention a compound selected from
C — (CH2)BCH3
The present invention will now be described in further detail in the following examples.
EXAMPLES
Enzymatic production of acetylated monoglyceride of hydrogenated castor oil.
Example 1
Lab journal No.: 2410/53 TLJ Materials:
Acetylated hydrogenated castor oil (TAC HCAO lot. no. 2332/121) Triacetin, item no. 021652, lot.no.4010172485
1.) Lipozyme TL IM, Novozymes, lot. No. LA35000405
2.) Lipozyme TL IM, Novozymes, lot. No. LA350012
3.) Lipozyme TL IM, Novozymes, lot. No. LA35002001
Lipase QLG, Meito Sangyo co., ltd, lot. No. QG9401 Lipase PLG, Meito Sangyo co., ltd, lot. No. PG 0X01
Lipase QLC, Meito Sangyo co., ltd, lot.no. QC3Z01
Lipase PLC, Meito Sangyo co., ltd, lot. No. PC2301
Lipase PS-D "Amano" I, Amano Enzymes, Inc, lot.No.lLPSAB015235R
Lipase PS-C "Amano" II, Amano Enzymes, Inc, lot. No. ILPSAC0252304R Lipase PS-C "Amano" I, Amano Enzymes, Inc, lot. No. ILPSAA0550903R
TAC HCAO, Triacetin and enzyme was mixed in 20 mL Wheaton glasses. The samples were placed in a heating block at 600C, with magnetic stirring. After 48 hours the reaction was stopped. The enzyme was removed by filtration. Samples were analyzed using gas chromatography (GC)
%MONO-2AC-18OAC is defined as weight % of the total sample of the group of molecules consisting of
12-acetyloxy-octadecanoic acid 2,3-bis-acetyloxy-propyl ester Mw=500.67 gram/mol and 12-acetyloxy-octadecanoic acid 1 ,3-bis-acetyloxy-prop-2-yl ester Mw=500.67 gram/mol.
Example 2-6: Continuous flow reactions in enzyme bed
Equipment Reactor, heat exchanger and packed bed enzyme reactor:
The reactor, heat exchanger and packed bed enzyme reactor were made of pipes of stainless steel. All connections and fittings were made with Swagelok fittings. Rockwool with a layer of aluminium foil on the outside was used as insulation of the pipes.
Dimension of the reactor was: Diameter outside: 25 mm
Diameter inside: 22 mm
Length: 770 mm
The reactor had a heated jacket. Dimension was:
Diameter outside: 38 mm Length: 400 mm
Example 2: Dewatering of enzyme bed:
The enzyme contains some water and to prevent hydrolysis and thereby formation of free fatty acids during reaction, the enzyme was dewatered. The dewatering was done by flushing the enzyme with TAC HCAO. The product from the dewatering was collected but was treated as waste.
Lab journal No.: 2381/138 Materials:
TAC HCAO, 2332/121 POA Lipozyme TL IM, LA3500012
80.0 g of enzyme (dry powder) was packed into the reactor. TAC HCAO was pumped though the reactor, and samples were collected. The acid value expressed as mg KOH
used to neutralise the free fatty acids in 1 gram of sample (AV) was determined by titration.
The dewatered enzyme packed bed reactor was used as reactor in example 3,4 and 5.
Example 3: Conversion of TAC HCAO and triacetin molar ratio 1 :3
Three different flow rates was investigated
Lab journal No.: 2381/140-2381/141 , 2410/1-2410/2
Material:
TAC HCAO, 2332/121 POA
Triacetin, item no. 021652, lot.no. 4010172485
Lipozyme TL IM, LA3500012
10.34 kg TAC HCAO and 6,50 kg Triacetin (TAC HCAO/ Triacetin molar ratio 1 :3) was mixed in a 25 L metal container. Pump setting 1 , 2 and 4 were investigated, the flow rate was measured and the conversion was determined by GC analysis.
Example 4: Conversion of TAC HCAO and triacetin molar ratio 1 :2
Three different flow rates was investigated
Lab journal No.: 2410/1 Materials:
TAC HCAO, 2332/121 POA
Triacetin, item no. 021652, lot. no. 4010172485 Lipozyme TL IM, Batch LA350012
3.1998 kg TAC HCAO and 1.3020 kg Triacetin was mixed in a 10 L metal container. Pump setting 1 , 2 and 4 were investigated, the flow rate was measured and the conversion was determined by GC analysis.
Example 5: Conversion of TAC HCAO and triacetin molar ratio 1 :5
Three different flow rates was investigated Lab journal No.: 2410/2
Material: TAC HCAO, 2332/121 POA
Triacetin, item no. 021652, lot.no. 4010172485 Lipozyme TL IM, Batch LA350012
2.1366 kg TAC HCAO and 2.1906 kg Triacetin was mixed in a 10 L metal container. Pump setting 1 , 2 and 4 were investigated, the flow rate was measured and the conversion was determined by GC analysis.
*The sample was not homogeneous
Example 6: Distillation of product.
Lab journal No.: 2314/121 HV, 2314/122 HV
Material: 2410/5 TLJ a mixture of 2381/140-2 and 2381/140-3, products of experiment 3
The distillation was made in two steps. In step 1 Triacetin was removed by water vapour distillation. 1264 g sample were water vapour distilled at 1800C in 45 min at <0,5mbar. Yield was 857 g.
In step 2 the product from step 1 was distilled on a short path distiller. 729 g sample was distilled at 2300C at 0.6 Pa. The yield was 329 g. The product was analysed on GC and acid value and colour was measured.
Analytical results:
Examples 7-12
Raw materials and solvents
Example 7
Preparation of acetylated hydrogenated castor oil from a mixture of hydrogenated castor oil and acetic acid anhydride.
Equipment:
50 L stainless steel reactor with electrical heating, mechanical stirring, water vapour supply, distillation column, condenser, distillate collector and vacuum equipment.
Experiment:
24 kg hydrogenated castor oil flakes were added to the reactor together with 8.4 kg acetic acid anhydride and heated to 800C where the stirring was turned on. The reaction started at 1200C and the temperature allowed to rise.
Example 8
Preparation of acylated hydrogenated castor oil from a mixture of hydrogenated castor oil and dodecanoyl chloride in methylene chloride using pyridine as a catalyst.
Equipment:
5000 mL three necked reaction flask equipped with temperature control, reflux condenser, mechanical stirrer, pressure equalising dosing funnel, nitrogen supply and drying tube. 5000 mL separation funnel, filtration equipment and rotary evaporator.
Experiment:
275 gram of hydrogenated castor oil was dissolved in 2400 mL dry methylene chloride (kept dry over molecular sieve) at 4O0C. The solution was cooled to 300C and 62 gram of pyridine was added. 169 gram of dodecanoyl chloride was dissolved in 250 mL dry
methylene chloride and added to the dosing funnel. The dodecanoyl chloride solution was added slowly to the reaction mixture during 3 hours keeping the temperature at 3O0C.
To the reaction mixture was added 600 ml. 3O0C warm demineralised water and the mixture was separated in the separation funnel. The organic phase was washed twice with additional 600 ml. 300C warm demineralised water. The organic phase was kept at 3O0C and dried with Mg-sulphate.
The dry organic phased was filtered and concentrated in a rotary evaporator at 400C and 30 kPa for 30 min and 700C for 30 min.
Yield 439 gram of 1 ,2,3-tri-(12-dodecanoyloxy-octadecanoyloxy)-propane (Mw: 1486.39 gram/mol)
Example 9
Drying of immobilised enzyme preparation of Thermomyces lanuginosa lipase Lipozyme TL IM (Novozyme A/S) with acetylated hydrogenated castor oil (1 ,2,3-tri-(12- acetylxy-octadecanoyloxy)-propane)
Equipment:
3000 mL three necked reaction flask with temperature control, mechanical stirrer and nitrogen cover.
Experiment:
1054 gram of acetylated hydrogenated castor oil was placed in the reactor with 147 gram of Lipozyme TL IM and heated to 6O0C for 24 hrs in order to hydrolyse the (12- acetyloxy-ocatadecanoic acid moieties from the glycerol backbone using the water which was added with the enzyme (water content of the enzyme was about 7%).
The reaction mixture was decanted from the enzyme, and the enzyme was used in example 3 and 5.
Example 10
lnteresterification of triacetin with 1 ,2,3-tri-(12-dodecanoyloxy-octadecanoyloxy)- propane (product of example 8) using the dried enzyme of example 9 as catalyst, removal of excess triacetin and recover of the main product 12-dodecanoyloxy- ocatadecanoic acid 2,3-bis(acetoxy)-propyl ester (Mw: 640.93 gram/mol) and its positional isomer 12-dodecanoyloxy-octadecanoic acid 2-acetoxy-1-acetoxymethyl- ehtyl ester (Mw. 640.93 gram/mol) (LODA)
Equipment: 3000 ml. three necked reaction flask with temperature control, mechanical stirrer and nitrogen cover. 5000 mL distillation equipment with Claissen head, water vapour addition tube and vacuum equipment, Filtration equipment and molecular distillation equipment (KDL 5 from UIC Gmbh.)
Experiment:
Three reactions with 1000 gram of 1 ,2,3-tri-(12-dodecanoyloxy-octadecanoyloxy)- propane (product of example 8) was placed in the reactor and mixed with the dried enzyme of example 2 and 470 gram of triacetin was added. The reactor was heated to 6O0C and reacted for 24 hours. The enzyme was removed by filtration and the reaction mixture was placed in a 5000 mL distillation equipment and heated to 18O0C at reduced pressure of 0.2 kPa with water vapour addition for 1.5 hours to remove excess triacetin from the reaction mixture. 2623 gram of a concentrated reaction mixture was treated in a molecular distillation equipment at 255°C, 0.7 Pa and a flow of 786 gram/hour. 1346 gram or 51.3% was recovered as distillate. The enzyme from Example 12 was reused in the following reaction.
The distillate was analysed by gas chromatography (GC) and consist of 56 weight % of a mixture of 12-dodecanoyloxy-ocatadecanoic acid 2,3-bis(acetoxy)-propyl ester (Mw: 640.93 gram/mol) and its positional isomer 12-dodecanoyloxy-octadecanoic acid 2- acetyloxy-1-acetoxymethyl-ehtyl ester (Mw. 640.93 gram/mol) in the ration 2:1.
Example 11
Preparation of acylated hydrogenated castor oil from a mixture of hydrogenated castor oil and decanoyl chloride in methylene chloride using pyridine as a catalyst.
Equipment:
5000 mL three necked reaction flask equipped with temperature control, reflux condenser, mechanical stirrer, pressure equalising dosing funnel, nitrogen supply and drying tube. 5000 mL separation funnel, filtration equipment and rotary evaporator.
Experiment:
275 gram of hydrogenated castor oil was dissolved in 2300 mL dry methylene chloride (kept dry over molecular sieve) at 400C. The solution was cooled to 3O0C and 62 gram of pyridine was added. 148 gram of decanoyl chloride was dissolved in 250 mL dry methylene chloride and added to the dosing funnel. The decanoyl chloride solution was added slowly to the reaction mixture during 3 hours keeping the temperature at 380C.
The reaction mixture was added 600 mL 300C warm demineralised water and the mixture was separated in the separation funnel. The organic phase was washed twice with additional 600 mL 300C warm demineralised water. The organic phase was kept at 30°C and dried with Mg-sulphate.
The dry organic phased was filtered and concentrated in a rotary evaporator at 4O0C and 30 kPa for 30 min and 7O0C for 30 min.
Yield 415 gram of 1 ,2,3-tri-(12-decanoyloxy-octadecanoyloxy)-propane (Mw: 1402.23 gram/mol)
Example 12
lnteresterification of triacetin with 1 ,2,3-tri-(12-decanoyloxy-octadecanoyloxy)-propane (product of example 11) using the dried enzyme of example 2 as catalyst, removal of excess triacetin and recover of the main product 12-decanoyloxy-ocatadecanoic acid 2,3-bis(acetoxy)-propyl ester (Mw: 612.88 gram/mol) and its positional isomer 12- decanoyloxy-octadecanoic acid 2-acetoxy-1-acetoxymethyl-ehtyl ester (Mw. 612.88 gram/mol) (DODA)
Equipment: 3000 mL three necked reaction flask with temperature control, mechanical stirrer and
nitrogen cover. 5000 mL Distillation equipment with Claissen head, water vapour addition tube and vacuum equipment, filtration equipment and molecular distillation equipment (KDL 5 from UIC Gmbh.)
Experiment:
Three reactions with 1000 gram of 1 ,2,3-tri-(12-decanoyloxy-octadecanoyloxy)-propane (product of example 11) was placed in the reactor and mixed with the used enzyme of example 10 and 470 gram of triacetin was added. The reactor was heated to 600C and reacted for 24 hours. The enzyme was removed by filtration and the reaction mixture was placed in a 5000 mL distillation equipment and heated to 1800C at reduced pressure of 0.2 kPa with water vapour addition for 1.5 hours to remove excess triacetin from the reaction mixture. 2623 gram of a concentrated reaction mixture was treated in a molecular distillation equipment at 255°C, 0.7 Pa and a flow of 786 gram/hour. 1346 gram or 51.3% was recovered as distillate.
The distillate was analysed by GC and consist of 71 weight % of a mixture of 12- decanoyloxy-ocatadecanoic acid 2,3-bis(acetyloxy)-propyl ester (Mw: 612.88 gram/mol) and its positional isomer 12-decanoyloxy-octadecanoic acid 2-acetyloxy-1- acetoxymethyl-ehtyl ester (Mw. 612.88 gram/mol) in the ration 2:1.
All publications mentioned in the above specification are herein incorporated by reference. Various modifications and variations of the described methods and system of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are obvious to those skilled in chemistry or related fields are intended to be within the scope of the following claims.