F0RM2
THE PATENTS ACT, 1970 (39 of 1970)
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION:"PREPARATION OF ESTERS FROM 2-OCTANOL"
2. APPLICANT
NAME : UDESHI SUBHASH VITHALDAS
NATIONALITY:INDIAN
ADDRESS : Jayant Agro Organics Ltd,Akhandanand, 38, Marol Co-operative Industrial Estate, Off M. V. Road, Sakinaka, Andheri (E),Mumbai-400 059, India.
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF THE INVENTION:
The present invention relates to a process for preparing esters from capryl alcohol using catalysts. In process of invention, esterification of 2-octanoI with various acids and anhydrides and organo-metallic catalysts is carried out which results in light colored esters with no significant impurities. Further process of invention does not require further refinements for purification of the ester except filtration for solid spent catalysts.
BACKGROUND AND PRIORART OF THE INVENTION:
India is the major producer and exporter of castor oil and its derivatives, together with deoiled castor cake. Most derivatives of castor oil have important industrial applications. Sebacic acid is one such derivative obtained by alkali fusion of castor oil and/ or castor oil fatty acids. 2-octanol and 2-octanone, co-products of this process, can be converted into value added products.
2-octanol is a secondary alcohol with eight carbons. It has some similar chemical properties in relation to 2-ethyl hexanol and I-octanoI. It undergoes similar chemical reactions as other alcohols such as esterification, dehydration, etherification, ethoxylation, sulfation, etc. However, the purity of 2-octanol during sebacic acid process varies from 76-83%, the rest being mainly 2-octanone.
2-ethyl hexanol (2EH) is obtained from petrochemical feedstock and has an established outlet in the manufacture of various esters e.g. dioctyl phthalate (DEHP), dioctyl adipate (DEHA), dioctyl sebacate (DEHS). A growing area for 2-EH has been its use in the manufacture of corresponding acrylates which are used for acrylic emulsion polymers for pressure-sensitive adhesives, textiles and surface coatings,

which includes high-solids automotive paints. It is known that petroleum materials like 2-ethyl hexanol or 1-octanol, used in the process of manufacturing esters, are net emitters of carbon dioxide.
Like 2-ethyl hexanol, 2-octanol can be used to prepare derivatives.Also, as mentioned above 2-octanol is derived from agro-based product viz. castor oil from the castor plant. Castor plant absorbs CO2 from the atmosphere. Thus, using 2-octanol in place of 2-ethyl hexanol or 1-octanol has an added advantage of lowering global warming potential as it leads to lesser carbon dioxide emissions.
Extensive literature is available for the preparation of the esters especially phthalates using phthalic anhydride (PAN), alcohols and different catalysts and their life cycle assessment (LCA).
However, the esterification of the various acids and anhydrides with capryl alcohol is a very slow reaction and thus requires long time to obtain maximum conversion to their esters. When esterification was carried out using acid catalyst, side reactions took place resulting in impurities and lower recoveries. The side reactions are dehydration and etherification of the 2-octanol in presence of acid catalysts. For example, when the esterification of 2-octanol with various acids and anhydrides is carried out using para-toluene sulfonic acid (p-TSA) as a catalyst, there are side reactions and impurities such as octenes and ethers as result of dehydration and etherification of 2-octanol respectively. These reactions generally occur in the presence of acid catalysts and at high temperatures. These reaction and impurities subsequently result in darker colored final ester products and hence require further processes of refinement to make these esters saleable. These additional steps add to the process cost making it a very expensive process.

In addition, the aforementioned side reactions led to the conversion of the excess 2-octanol into other products and thus higher quantity of 2-octanol will be required.
Thus, at present the esterilication of 2-octanol has been found to be difficult either due to incomplete conversion, darker colored esters, impurities, and higher usage of 2-octanol compared to other alcohols e.g. 2-ethyl hexanol. Also, there is a need for an economical and feasible process of esterification of 2-octanol using various acids and anhydrides.
The objective of this work is to prepare esters from 2-octanol obtained from a renewable resource. In this investigation, the inventors have made efforts to synthesise the esters based on different grades (purities) of 2-octanol by reacting with various anhydrides and acids and different catalysts. Lot of efforts have been made to optimize the reaction parameters such as purity of reactants especially, 2-octanol, molar ratio of the reactants like 2-octanol and acids & anhydrides, type of catalyst and their dosage based on the weight of the solid, reaction temperatures, analysis of the reactants and products and esters refinement. Thus, longer period has been required to develop this art for the desired process and products.
The inventors of the present invention have found out that the developed processes for esterification of 2-octanol with various acids and anhydrides and organo-metallic catalysts achieves light colored esters with no significant impurities. Further, these processes do not require further refinements for purification of the ester except filtration for solid spent catalysts.
As evident from the prior art, it becomes challenging to formulate a processes for esterification of 2-octanol with various acids and anhydrides and organo-metallic catalysts achieves light colored esters with no significant impurities. Thus, the present

invention holds an advantage of the processes that do not require further refinements for purification of the ester except filtration for solid spent catalysts. The discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.
OBJECT OF THE INVENTION
Accordingly, one of the objects of the present invention is toprovide a process for esterification of 2-octanol with various acids and anhydride and organo-metallic catalysts.
Another object of the present invention is to provide a process for esterification of 2-octanol with various acids and anhydrides and organo-metallic catalysts where the desired level of conversion of the acids and anhydrides into their capryl esters with light appearance was obtained.
Yet another object of the invention is to provide a process for esterification of 2-octanol at higher catalyst loading and higher temperature to achieve light colored esters with no significant impurities in short reaction time.
Further object of the present invention is to provide dicapryl esters from 2-octanol whose performance as plasticizer are almost comparable or in some aspects better than the commercially used plasticizers.

SUMMARY OF THE INVENTION:
In accordancewith the present invention, there is described a process for preparing esters comprising reacting acids or anhydrides with 2-octanol in the presence of a high amount of organo-metallic catalyst at a higher reaction temperature thereby reducing the reaction time, wherein the 2-octanol is used in excess over the stoichiometric requirement for the maximum conversion and the said excess alcohol is recovered by distillation under reduced pressure at the end of the reaction, and the concentration of the catalyst is more than 0.1% by weight based on the weight of the solid.
STATEMENT OF INVENTION:
The present invention relates to a process for preparation of esters from capryl alcohol (2-octanol) comprising steps of
a) reacting capryl alcohol with acids or anhydrides in the presence of tin based catalyst having atleast 45% of tin and is carried out in temperature range about of 190-250°C preferably at about of 190-230°C and is carried out with 10-30 weight percent of alcohol in excess based on stoichiometry
b) removing catalyst by filtration
c) separation of capryl aIcohol(2-octanol) by distillation under reduced pressure for recycling
wherein concentration of the catalyst is atleast 0.1% by weight based on the weight of the solid and the tin content is atleast 0.05%, the organotins catalyst are selected from stannous oxalate and their variants, the concentration of catalyst is preferably in the range of 0.1-0.5% by weight based on the weight

of the solid. The acid is sebacic acid, adipic acid, fumaric acid, benzoic acid, acrylic acid, methacrylic acid, fatty acids with carbon range C12 to C18, methyl ester of methacrylic acid, the anhydride is phthalic anhydride or maleic anhydride.Esters formed in stage a) of claim 1 are treated with 1 % of an admixture of an equal amount of the activated bleaching earth and carbon at temperature 110°C for 25 min. The capryl alcohol used is 50 to 100 % pure. The ester produced is dicapryl phthalate, dicapryl sebacate, dicapryladipate, dicapryl maleate, capryl benzoate, dicaprylfumarate, capryl methacrylate or fatty acid esters.
DESCRIPTION OF THE INVENTION
As described herein, the preferred embodiments of the process could be used in the manufacture of various esters including but not limited todicapryl phthalate (DC?), dicaprylsebacate (DCS), dicapryladipate (DCA), dicapryl maleate (DCM), Capryl benzoate (CB), dicaprylfumarate (DCF), and the like.
Esters were synthesized using different grades of 2-octanol, acids and anhydrides, and three different catalysts. When the esterification was carried out using 2-octanol, acids and anhydrides, and organo-metallic catalysts such as stannous oxalate or titanates, and reaction temperature between 190-220°C, the desired level of conversion of the acids and anhydrides into their capryl esters with light appearance was obtained. No further processes are essential for ester purification but only filtration for removal of the spent catalyst in case of the tin-based catalysts.

Alcohol:
2-octanol (also referred to as capryl alcohol to distinguish from other octanols) is a co-product formed during the industrial manufacturing of sebacic acid from castor oil and /or castor oil fatty acids.
2-octanol from sebacic acid manufacture is collected as a distillate together with 2-octanone as a by-product This is designated as grade A {purity 82.7%). It is then dried under vacuum to get grade B (purity 84.04%). This quality 2-octanol is flash distilled to get grade C (purity 85.0%). While grade D 2-octanol (purity 99.80%) is obtained by fractionation of 2-octanol-2-octanone mixture. Grade E 2-octanol (purity 59.99%) is recovered from laboratory esterification batches by distillation. All these were used in the present process.
In addition to the catalyst type and concentration, an excess amount of the capryl alcohol plays an important role to increase the conversion and to obtain light colored esters. Therefore, 2-octanol was used in excess over the stoichiometric requirement. The preferred range is from 10-20 excess weight % of alcohol based on stoichiometry.
However, the excess 2-octanol can be recovered and directly reused for esterification reactions without refinement as no significant impurities are formed which would otherwise contaminate it.
Acids and Anhydrides:
In the present process, 2-octanol is reacted with various acids and anhydrides in the presence of a catalyst. Suitable examples of acids and anhydrides include phthalic anhydride, maleic anhydride, sebacic acid, adipic acid, fumaric acid, benzoic acid and the like.

Catalysts:
Significant dehydration of 2-octanol to octenes and dicapryl ethers was observed when acid catalysts like p-TSA were used. It has been observed that acidic catalysts & longer esterification periods& higher reaction temperaturesproduce colored products & lesser recovery due to side reactions. Also, the excess 2-octanol used over the stoichiometric quantity requirement is lost. The acid catalyst, p-TSA, was used in the present process for comparison with other preferred catalyst. In case of p-TSA, the reaction temperature was maintained between 180-190°C.
However, in the inventive esterification, when organo-metallic catalysts are used at certain dose, the desired conversions of the acids and anhydrides into esters with lighter appearance were found. Also, higher dose of the organo-metallic catalysts gave good conversion and even reduced the reaction time by four to five folds. In addition, there are no significant side reactions that were seen when p-TSA was used. Hence, no further processes of refinements for ester were required except filtration. Also, the excess 2-octanol is recovered and can be directly reused in the esterification reactions. Thus, the overall cost estimation reveals that the inventive processes for esterification of 2-octanol are more feasible and economical.
Suitable examples of organo-metallic catalysts include stannous oxalate (FASCAT 2001& SV CAT-100) and titanate (TIPT, BTM). In the present process, two grades of stannous oxalate were preferred: Tin content 56-57% and 57.3%. The concentration of catalyst was in the range of 0.1-0.5% by weight based on the weight of the solid, in particular from 0.2%-0.5% by weight. The concentration of the organo-metallic catalyst is an essential feature of the present process.

When organo-metallic catalysts were used, the reaction temperature of the esterification process was maintained between 190-220°C. The inventors of the present invention have found that the higher reaction temperature (220°C) and higher catalyst loading (>0.1%) shortened the reaction time and improved the color quality of the final product as well as the recovery.
Esterification: Synthesis of DicaprylPhthaIate(DCP)
In the esterification, reactions were carried out in a round bottom glass flask reactor provided with a mechanical stirrer, Dean Stark Apparatus, and a thermometer. The flask was placed in an electrical heating mantle. Weighed quantities of reactants and catalyst were charged to the reactor and heated to the desired temperature. The catalytic reaction was allowed to progress. The reaction was monitored by periodically withdrawing the reaction mass samples and determining the Acid Value (AV) by using respective AOCS Official Methods. Water formed during the reaction was separated and removed from Dean Stark Apparatus.
Excess alcohol used in the reaction was recovered by distillation under reduced pressure at the end of the reaction. The reaction mass was then cooled to 30°C under nitrogen atmosphere and the organo-metallic catalyst was removed by filtration. The filtered mass was bleached with an admixture of an equal amount of activated bleaching earth and carbon.
The performance of the DCP, prepared in the laboratory was compared with
commercial plasticizers such as di-2-ethy hexyl phthalate (DEHP) and di-isononyl
phthalate (DINP).
The present invention is further described with the help of the following examples, which are given by way of illustration all the parts, percent's and ratios are by weight

unless otherwise indicated and therefore should not be construed to limit the scope of the invention in any manner.
EXAMPLES:
The present invention will now be illustrated with the examples. The examples
are by the way of illustration only and in no way restrict the scope of invention. Fifteen batches for synthesis of DCP were carried out and these were labeled as L/DCP/B1, L/DCP/B2, L/DCP/B3 A, L/DCP/B3 B, L/DCP/B4, L/DCP/B5, L/DCP/B6, L/DCP/B7, L/DCP/B8, DDCP/B9, L/DCP/B10, L/DCP/B11, L/DCP/B12, L/DCP/B13, AND L/DCP/B14 The details of the reaction parameters are given in Tablet.
Table 1: Reaction parameters used in the preparation of dicapryl phthalate

Catalyst (%)
Sr. Batch 2-octanol: Toluene Rxn.

SV CAT-

Quality of PAN.
No. No 2-octanol Mole ratio p-TSA 100/ FASCAT
2001 (g) Temp.
(°C)
1 L/DCP/B1 A 4.39 1.95 - - 190
2 L/DCP/B2 B 4.39 0.5 - - 190
3 L/DCP/B3 A C 3.43 - 0.1 - 135
4 L/DCP/B3/B C 3.43 - 0.1 - 220
5 L/DCP/B4 C 4.37 - 0.1 - 220
6 L/DCP/B5 E 3.85 - 0.1 - 220
7 L/DCP/B6 C 2.21 0.5 - 71.0 120

8
L/DCP/B7 D 4.59 1.34 - - 190
9 L/DCP/B8 D 5.64 1.34 - - 190
10 L/DCP/B9 D 5.73 - 0.15 - 220
11 L/DCP/B10 D 2.23 1.34 - 98.0 120
12 L/DCP/B11 D 2.91 - 0.15 - 220
13 L/DCP/B12 D 3.19 - - - 220
14 L/DCP/B13 D 2.22 - o.1+ - 220
15 L/DCP/B14 D 2.42 - 0.5+ - 220
L/DCP : Name of the batch indicates laboratory synthesis of dicapryl phthalate
Rxn. : Reaction
Temp. : Temperature
+ : Batches were carried out using FASCAT 2001
Esterification using p-TSA
Six batches namely L/DCP/B1, L/DCP/B2, L/DCP/B6, L/DCP/B7, L/DCP/B8, and L/DCP/B10 were carried out using p-TSA as a catalyst. The different catalyst loadings based on the total charge were employed for esterification. There were two batches viz. L/DCP/B6 and L/DCP/B10 carried out using toluene and different grades of 2-octanol like grade A and grade D.
When the esterification was carried out at reaction temperature 190°C using p-TSA as a catalyst, grade A 2-octanol and PAN, >98% conversion of PAN into its ester was found within 10 hours of reaction time. However, the appearance of the DCP was found very dark (>18G).

In addition, when p-TSA was used as a catalyst, the reaction mass showed presence of two by-products, which were identified as octenes and dicapryl ethers, Both are formed by dehydration of 2-octanol.
Furthermore, apart from quality of 2-octanol as far as the color of DCP is concerned, an influence of the type of catalysts on final appearance of DCP is also important. When the DCP was prepared in the presence of p-TSA, the final appearance of DCP was found very dark. Whereas, when organo-metallic catalysts were used, the appearance of the DCP was improved. From these observations, it is clear that p-TSA produces some color bodies along with co-products like alkenes and ethers. Conversion
Six batches of esterification namely L/DCP/B1, L/DCP/B2, L/DCP/B6, L/DCP/B7, L/DCP/B8 and L/DCP/B10 using para-toluene sulfonic acid, and different grades of 2-octanol were carried out. Of these, the batches such as L/DCP/B6, and L/DCP/B10 were carried out using toluene as solvent, and other batches were carried out without a solvent.
In batch L/DCP/BI, more than 98 % conversion of PAN was found when the reaction was carried out for 10 hours using grade A-2-octanol and 1.95 % p-TSA as a catalyst. While, in batch L/DCP/B2, more than 83 % conversion of PAN was obtained when the reaction was carried out for 6 hour using grade B2-octanol and 0.5 % p-TSA as a catalyst.
The batches L/DCP/B7 and L/DCP/B8 of esterification were carried out using grade D2-octanol. It was found that % conversion and the color of the DCP was almost the same in these two batches. The percent conversion and batch time for former and latter batches were >99 % and 14 and 16 h respectively.

In batch L/DCP/B6, the conversion was nearly 77 % at the end of 11 h. The catalyst concentration was increased from 0.5 to 1.34 % for the batch L/DCP/B10. However, the conversion of nearly 97 % was obtained only after 27 h reaction time. This longer time of reaction in both the cases was due to lower reaction temperature (120°C) realized because of refluxing toluene.
Esterification using Organo-metallic catalysts
Two organo-metallic catalysts viz. SV CAT-100 and FASCAT 2001 were used in the reaction. Eight batches of esterification namely L/DCP/B3 A, L/DCP/B3 B, L/DCP/B4, L/DCP/B5, L/DCP/B9, L/DCP/B11, L/DCP/B13, and L/DCP/B14 were carried out. Of these, six batches such as L/DCP/B3 A, L/DCP/B3 B, L/DCP/B4, L/DCP/B5, L/DCP/B9, L/DCP/B11 were carried out using SV CAT-100 as a catalyst and rest of the batches of esterification were carried out using FASCAT 2001.
In first batch L/DCP/B3 A esterification of PAN was carried out using grade C 2-octanol at reaction temperature 135°C and 0.1 % of the catalyst based on the weight of solid (PAN). More than 56 % conversion within twelve and half hour of reaction time, and the color of reaction mass was 12 G was obtained. When the same batch was continued (L/DCP/B3 B) but at higher reaction temperature (220°C) and >99.5 % conversion was found within 7 - 8 h of reaction time. Colour of DCP produced in this batch increased to 15 G. The sample from this batch was analyzed by GLC for product (DCP) and impurities, there were no significant peaks observed on chromatogram apart from peaks of 2-octanol and DCP.
Further, the reaction mass of batch (L/DCP/B3B) showed only trace of octenes and ethers even at 220°C of reaction temperature. The organo-metallic catalyst was found in the reaction mass as suspended particles and was easily

separated by filtration, and the reaction mass did not require water extraction for the catalyst removal (p-TSA) and hence drying. The dark color of final DCP was observed in this batch due to either the quality of the 2-octanol or the reaction mass was exposed to heat for prolonged period (> 21 h). However, it was clear from the result of these two batches that organo-metallic catalyst works well at high temperatures. Thus, one of the reaction parameter for esterification of PAN using organo-metallic catalyst was optimized
Batch L/DCP/B4 of esterification was carried out for only 3 h and the remaining parameters were as same described earlier. However, the color of reaction mass from this batch was found dark (10G) and hence it was concluded that the quality of 2-octanol is ultimately affecting the color property of the ester DCP. Similarly, in another batch L/DCP/B5 esterification of PAN was carried out using low purity of 2-octanol (<60%) recovered from other laboratory reaction batches. Only 68 % conversion of PAN was found when the reaction carried out for 13 h at 220°C. The low conversion of PAN could be due to the purity of 2-octanol (grade E2-octanol).
Based on the above observations, two batches L/DCP/B9 and L/DCP/B11 were carried out using higher % of catalyst (0.15%) and with changed mole ratio of reactants. The mole ratio of 2-octanol to PAN for former and latter batches was 5.73 and 2.22 including the excess alcohol required for Dean and Stark Apparatus. When more excess 2-octanol was used in the reaction, the required reaction temperature (220°C) was not achieved even after 2 h of reaction due to lower bubble point of the reaction mass. It was found that when 20 % excess 2-octanol was used based on the stoichiometricrequirement, the reaction temperature was reached earlier (approximately one h).

The batches L/DCP/B13, and L/DCP/B14 of esterification were carried out at 220°C using grade D2-octanol and FASCAT 2001 as a catalyst. The mole ratio of 2-octanol to PAN and the % of catalyst for former and latter batch was 2.22 and 2.42, and 0.1 and 0.5 % based on the weight of PAN, respectively.
In batch L/DCP/B13 of esterification of PAN using 10% excess alcohol and 0.1% catalyst at 220°C the rate of reaction was fast for initial 4 h, but after 5 h, the rate of esterification of PAN became sluggish. After 5 h reaction, the water of reaction did not separate from distilled organic phase. Reaction was further carried out for 30 h, % conversion of PAN was found more than 95 %. The slower rate of reaction in this could be because of the lower concentration of reactants towards end of the reaction in the reaction mass, particularly that of 2-octanol, which was only 10 % excess as compared to 20% or more used in the experiment.
A large size batch L/DCP/B14 (1.5 kg) was carried out using 20% excess 2-octanol based on the stoichiometry requirement and 0.5% FASCAT 2001. In this batch AV dropped very rapidly to less than 1 within three hr. Thereafter 2-octanol (10 gm) was intermittently removed from Dean and Stark Apparatus and fresh 2-octanol was added (10 g). The final acid value of reaction sample was found 0.26 mg KOH/g, corresponding to 99.88 % conversion of PAN. The color of final DCP was +3G.The DCP obtained from the batch L/DCP/B14 of esterification of PAN was treated with 1 % of an admixture of an equal amount of the activated bleaching earth and carbon at temperature 110°C for 25 min. The filtration was done for bleached DCP using a filter aid bed under reduced pressure. The color of the DCP before and after bleaching was measured using LCC & GD, and was +3 and +1, respectively. The analysis report of the bleached DCP is given in Table 3.

In batch L/DCP/B12 esterification of PAN was carried out without catalyst at 220CC as control batch. Maximum % conversion of the PAN into DCP was found nearly 90 % when the reaction was carried out without catalyst. The final appearance of the DCP was also very dark (Table 2).
Table 2: % conversion, batch time, initial and final color of DCP ester

Sr.
No. Batch
No Batch Time
(h) Conv. (%) Colour (Gardner)
1 L/DCP/B1 10 98.44 >18
2 L/DCP/B2 6 83.72 >18
3 L/DCP/B3/A 12.5 56.75 12
4 L/DCP/B3/B 7.25 99.71 15
5 L/DCP/B4 3 52.14 10
6 L/DCP/B5 13 68.12 8
7 L/DCP/B6 11 77.24 8
8 L/DCP/B7 14 99.42 11
9 L/DCP/B8 16 99.21 12
10 L/DCP/B9 27.75 99.03 12
11 L/DCP/B10 25 97.30 10
12 L/DCP/B11 23 99.95 12
13 L/DCP/B12 20 90.85 15
14 L/DCP/B13 34 96.52 +8
15 L/DCP/B14 12 99.88 +3

Conv. : Conversion
Results and discussion: Effect of purity of 2-octanol on color of DCP
Different grades of 2-octanol were used in the preparation of DCP. When grade A2-octanol was used, the color of DCP was found to be more than 18 Gardner Scale (G) in the presence of both acid and organo-metallic catalysts. When DCP was prepared separately using grade B and grade C2-octanol, similar observation was found. However, the color of the DCP was improved when the DCP was prepared using grade D2-octanol (purity >99 %) in the presence of an organo-metallic catalyst like SV CAT-100. The findings are given in the Table 3.
Table 3: Analysis of bleached dicapryl phthalate (DCP)

Sr. Parameters Unit Result Values
No.
1 Appearance Light Yellow
Transparent Oily
Liquid
2 Color Gardner Scale +1
3 Specific Gravity @ 20°C - 0.9551
4 Refractive Index @ 27°C - 1.4799
5 Moisture content (Karl Fischer) % 0.098
6 Relative Volatility @ 180°C/ 20 min % 0.014
7 Acid Value (As Acetic acid) % 0.0023
8 Saponification Value mg KOH/ gm 286

9
Ester % >99
10 Purity (GC) % >99
11 Flash point °C 200
12 Pour point °C -43
Furthermore, the color of the DCP was unproved when grade D2-octanol and FASCAT 2001 were used with certain modification in course of reaction. When the catalyst dose was increased five fold, the appearance further improved, and the color of DCP was found to be nearly +3 G (L/DCP/B14). This could be due to shorter reaction period. It was very essential to carry out bleaching process for reduction in color of the DCP by using an admixture of activated bleaching earth and carbon. The light appearance of DCP is important only for applications of the PVC formulations where DCP can be fully or partially used in place of DEHP, and/ or DINP. The lighter appearance of the DCP was found, when esterification was carried out in the presence of the solvent used for removal of the reaction water azeotropically. This was due to the lower reaction temperature 120°C. Moreover, the color of DCP can be improved significantly by bleaching using the mixture of activated bleaching earth and carbon.
The performance of the DCP, prepared in the laboratory was compared with commercial plasticizers such as di-2-ethy hexyl phthalate (DEHP) and di-isononyl phthalate (DINP).
Performance evaluation for general purpose
The performance evaluation of prepared DCP, DEHP and DINP for general purpose (GP) in paste polyvinyl chloride (PVC) formulations was evaluated. The purpose of

this assessment is to position DCP regarding GP phthalates and to assess its ability to act as a replacement for them. Both compact and foamy layers formulations were taken into account in these evaluations. Compact Layer Evaluation (CLE)
Transparent formulations (flooring-type, wear layers) were used for the evaluations. The transparent formulations for PVC were prepared based on the DCP and others plasticizers like DEHP and DINP using micro-suspension PVC resin of low viscosity andCa/Zn thermal stabilizer. The pastes were prepared in a high-speed mixer and de-aerated before assessment. Plasticizers were assessed for properties like rheology, paste ageing, air entrapment/ air release, hardness, thermal stability, water pick-up, color, transparency and gloss. The formulation details are given in Table 4. The findings are given in the Table 5.
Table 4: PVC formulation based on the DCP/ DEHP/DINP in Compact Layer Evaluation (CLE)

Sr.No Raw Material Parts (gm)
1 Micro-suspension low viscosity resin 100.0
2 Plasticizer(DCP/DEHP/DINP) 50
3 Ca/Zn thermal stabilizer 2.5

Table 5: Tested properties for PVC formulation based on DCP/DEHP/DINP in CLE

Sr. No. Properties DCP DINP DEHP
1 Rheology at low shear rate — 0 0
2 Rheology at higher shear rate 0 0 0
3 Paste ageing - 0 0
4 Air Release 0/+ 0 0
5 Efficiency 0/+ 0 +
6 Gloss 0 0 0
7 Transparency + 0 0
8 Yellow Index 0/- 0 0
9 Exudation 0 0 0
10 Odor 0 0 0
11 Weight Loss at 70°C 0 0 0/-
12 Thermal Stability 0 0 0
13 Water pick up + 0 0
0: Good ; +: Better ; -/--: Less desired
Few properties like rheology at low shear rate paste ageing and yellow index in DCP based PVC formulations were less desired. However, the other properties of the PVC formulation were found better than both DEHP and DINP based PVC formulations.
Foam Layer Evaluation (FLE)
Foam formulations (flooring-type, decor layers) were prepared using DCP, DEHP and DINP separately and used for the evaluations. The Pastes were prepared in a high-

speed mixer and de-aerated before assessment. The components of the PVC formulations are given in the Table 6.
Table 6: PVC formulation based on the DCP/ DEHP/DDSfP in Foam Layer Evaluation (FLE)

Sr. No. Raw Material Parts
1 Micro-suspension medium viscosity resin 100.0
2 Plasticizer(DCP/DEHP/DINP) 62.0
3 CaC03 40.0
4 MB (50%) Porofor ADC+DINP 6.0
5 Thermal stabilizer 2.0
The properties of the pastes such as rheology and paste aging, density, cell quality, expansion rate, yellow index and surface quality were tested. The findings for foam layer of PVC formulations prepared using DCP, DEHP and DINP are given in Table
7.

Table 7: Tested properties for PVC formulation based on DCP/DEHP/DINP in FLE

Sr. No. Properties DCP DINP DEHP
1 Rheology 0 0 0
2 Paste ageing 0 0 0
3 Yellow Index 0/- 0 0
4 Cell Quality 0 0 0
5 Surface Quality - 0 0
6 Cell Density 0 0 0
7 Expansion rate + 0 0
0: Good ; +: Better ; -: Less desired
The performance of DCP as a plasticizer in PVC formulation was almost comparable and better in some aspects than commercially used plasticizers such as DEHP and DINP.
The same invention could be used for esterification of 2-octanol with sebacic acid, adipic acid, fumaric acid, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, maleic anhydride, benzoic acid and the like.
All of the compositions and/or methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the compositions and/or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the invention. All such similar substitutes and modifications apparent to

those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims.

CLAIMS
1. A process for preparation of esters from capryl alcohol (2-octanol) comprising
steps of
d) reactingcapryl alcohol with acids or anhydrides in the presence of tin based catalyst having atleast 45% of tin.
e) removing catalyst by filtration
f) separation of capryl alcohol(2-octanol) by distillation under reduced pressure for recycling
wherein concentration of the catalyst is atleast 0.1% by weight based on the weight of the solid and the tin content is atleast 0.05%
2. A process for preparation of esters as claimed in claim 1, wherein the reaction of capryl alcohol with acids or anhydrides is carried out in temperature range about of 190-250°C
3. A process for preparation of esters as claimed in claim 1, wherein the reaction of capryl alcohol with acids or anhydrides is carried out in temperature range about of 190-230°C.
4. A process for preparation of esters as claimed in claim 1, wherein the reaction of capryl alcohol with acids or anhydrides is carried out with 10-30 weight percent of alcohol in excess based on stoichiometry.
5. A process for preparation of esters as claimed in claim 1, wherein the organotins catalyst are selected from stannous oxalate and their variants.
6. A process for preparation of esters as claimed in claim 1, wherein the concentration of catalyst is preferably in the range of 0.1-0.5% by weight based on the weight of the solid.

7. A process for preparation of esters as claimed in claim 1, wherein the acid is sebacic acid, adipic acid, fumaric acid, benzoic acid, acrylic acid, methacrylic acid, fatty acids with carbon range C12 to C18, methyl ester of methacrylic acid.
8. A process for preparation of esters as claimed in claim 1, wherein the anhydride is phthalic anhydride or maleic anhydride.
9. A process for preparation of esters as claimed in claim 1, wherein esters formed in stage a) of claim 1 is treated with 1 % of an admixture of an equal amount of the activated bleaching earth and carbon at temperature 110°C for 25 min.
10. A process for preparation of esters as claimed in claim 1, whereincapryl alcohol used is 50 to 100 % pure.
11. A process for preparation of esters as claimed in claim 1, wherein the ester produced is dicapryl phthalate, dicapryl sebacate, dicapryladipate, dicapryl maleate, capryl benzoate, dicaprylfumarate, capryl methacrylate or fatty acid esters.