Title of Invention

METHOD OF REMOVING METALS FROM HYDROCARBON FEEDSTOCK USING ESTERS OF CARBOXYLIC ACIDS

Abstract The present invention is related to removal of metals from hydrocarbon feedstock and more particularly to removal of calcium from the same. The method of removal of calcium from the hydrocarbon feedstock, comprises the steps of: (a)mixing the additive of the present invention, which is any one of the chemical compounds such as esters of various dicarboxylic acids such as monomethyl maleate, monomethyl oxalate, dimethyl maleate and ester of tricarboxylic acids such as citric acid and also esters of polycarboxylic acids or appropriate combination thereof in neat form or aqueous form or in solution with hydrocarbon, with any hydrocarbon feedstock stream such as crude oil, containing metal and its salts, such as calcium naphthenate, in a crude desalter; (b)permitting chemical reaction between the above mentioned additive and hydrocarbon feedstock; (c)permitting formation of two phases, that is, aqueous phase and the hydrocarbon phase; (d)separating the two phases of step (c) or permitting them separate.
Full Text FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
The Patent Rules, 2003
Provisional Specification
(See section 10 and rule 13)
Method of Removing metals from hydrocarbon feedstock using esters of
carboxylic acids
Dorf Ketal Chemicals (I) Pvt. Ltd
Dorf Ketal Tower, D'monte Street, Orlem, Malad (W), Mumbai, 400064 Maharashtra
State, India
An Indian company registered under the Companies Act, 1956
The following specification describes the invention:

METHOD OF REMOVING METALS FROM HYDROCARBON FEEDSTOCK USING ESTERS OF CARBOXYLIC ACIDS
FIELD OF INVENTION
The present invention is generally related to the field of hydrocarbon industry and particularly related to removal of metals from hydrocarbon feedstock and more particularly to removal of calcium from the same.
BACKGROUND OF INVENTION
Considering the rising prices of crude oil, the refiners are forced to process opportunity crude such as DOBA, to be competitive. However these opportunity crudes pose many problems such as fouling of heat exchangers, difficulties in effluent treatment, poisoning of catalyst by certain metallic salts and such other problems.
Among the metals, calcium poses very serious problems which cannot be tackled using the current refinery processes. Calcium exists in crude oil as calcium complex of naphthenic acid, which hereinafter is referred to as calcium naphthenate. The calcium naphthenate is not removed from the crude oil during the normal desalting process. The examples of the type of crude oil which contains large amounts of calcium naphthenate are crudes from China such as Shengli No. 2; DOBA from West Africa; Gryphon and Harding crude oil from the North Sea; and SJV from the West Coast of USA.
In an oil refinery, the desalting of crude oil has been practiced for many years. The crude is usually contaminated from several sources, including, metals including calcium, zinc, silicon, nickel, sodium, potassium, and such other metals.


Desalting is necessary prior to further processing to remove these compounds and other inorganic materials that would otherwise cause fouling and deposits in downstream heat exchanger equipment and/or form corrosive salts detrimental to crude oil processing equipment. Further, these metals can act as poisons for the catalysts used in downstream refinery units. Effective crude oil desalting can help minimize the effects of these contaminants on the crude unit and downstream operations. Proper desalter operations provide the following benefits to the refiner:
(a) Reduced crude unit corrosion.
(b) Reduced crude preheat system fouling.
(c) Reduced potential for distillation column damage.
(d) Reduced energy costs.
(e) Reduced downstream process and product contamination.
Desalting is the resolution of the natural emulsion of water that accompanies the crude oil by creating another emulsion in which about 5 percent relative wash water is dispersed into the oil using a mix valve. The emulsion mix is directed into a desalter vessel containing a parallel series of electrically charged plates. Under this arrangement, the oil and water emulsion is exposed to the applied electrical field. An induced dipole is formed on each water droplet within the emulsion that causes electrostatic attraction and coalescence of the water droplets into larger and larger droplets. Eventually, the emulsion resolves into two separate phases—the oil phase (top layer) and the water phase (bottom layer). The streams of desalted crude oil and effluent water are separately discharged from the desalter.
The entire desalting process is a continuous flow procedure as opposed to a batch process. Normally, chemical additives are injected before the mix valve to help resolve the oil/water emulsion in addition to the use of electrostatic coalescence.


These additives effectively allow small water droplets to more easily coalesce by lowering the oil/water interfacial tension.
Crude oil that contains a high percent of particulate solids can complicate the desalting process. The particulate solids, by nature, would prefer to transfer to the water phase. However, much of the solids in a crude oil from a field exists in tight water-in-oil emulsions. That is, oil-wetted solids in high concentration in the crude may help form tight oil and water emulsions that are difficult to resolve. These tight emulsions are often referred to as "rag" and may exist as a layer between the separated oil and water phases. The rag layer inside the desalter vessel may grow to such an extent that some of it will be inadvertently discharged with the water phase. This is a problem for the waste water treatment plant since the rag layer still contains a high percentage of unresolved emulsified oil.
Much of the solids encountered during crude oil desalting consists commonly as particulates such as iron oxide, iron sulfide, sand, clay and even phosphorus-containing compounds, etc. Other metals that are desirably removed include, but are not necessarily limited to, calcium, zinc, silicon, nickel, sodium, potassium, and the like, and typically a number of these metals are present. Some of the materials may be present in a soluble form, and some may require modification through reaction such as reaction or neutralization to become soluble. The metals may be present in inorganic or organic forms. In addition to complicating the desalter operation, phosphorus and other contaminants are of particular concern to further downstream processing. This includes the coking operation since iron and other metals remaining in the processed hydrocarbon yields a lower grade of coke. Removing the metals from the crude oil early in the hydrocarbon processing stages is desired to eventually yield high quality coke as well as to limit corrosion and fouling processing problems.
Several treatment approaches have been made to reduce total contaminant levels


and these all center on the removal of contaminants at the desalter unit. Normally, the desalter only removes water soluble inorganic salts such as sodium or potassium chlorides.
Basic metals such as calcium, when present in crude oil can lead to fouling of heaters and heat exchangers and poison catalysts used in crude processing. When present as inorganic salts, such as, chlorides, usually in an oil - encapsulated water phase, the salts can hydrolyze to release corrosive mineral acids. Refinery desalters customarily remove such salts. However, oil - soluble metal salts such as naphthenates and phenolates are not removed by conventional desalting. Therefore, oil - soluble, basic metal - rich crudes are less valuable than crudes with low levels of such metals. A process for metal ion removal enables the increase of the value of such crudes.
A few, but increasingly important, petroleum crude feedstocks, residua, and deasphalted oil derived from them, contain levels of calcium or iron which render them difficult, if not impossible, to process using conventional refining techniques. The metals contaminants causing particular problems are in the form of nonporphyrin, organometallically bound compounds. These species have been attributed to either naturally occurring calcium complexes or solubilized calcium from recovery waters that comes in contact with crude oils. One possible class of calcium compounds identified in particular is the respective naphthenates and their homologous series. These organometallic compounds are not separated from the feedstock by normal desalting processes, and in a conventional refining technique they can cause the very rapid deactivation of hydroprocessing catalysts. Examples of feedstocks demonstrating objectionably high levels of calcium compounds are crudes from China such as Shengli No. 2; DOB A from West Africa; Gryphon and Harding crude oil from the North Sea; and SJV from the West Coast of USA.


US Patent Application 0050241996 describes the use of only poly(acrylic acid) derivatives, (that is, polymers) for removing metal irons from hydrocarbon feedstocks. Even though this patent has listed 16 representative non - ionic water soluble monomers, 27 representative anionic monomers and 30 cationic monomers, wherein list of anionic monomers include maleic acid and fumaric acid, there is absolutely no suggestion or teaching in this patent, that any of these monomers can be used independently or in combination for removing metal ions from the hydrocarbon feedstocks. There is insistence in this patent on use of aqueous solution of only one or more water - soluble poly (acrylic acid) derivatives, that is use of polymers for the purpose of this US Patent Application.
It is known to a person skilled in the art that, it is necessary that a catalyst is used to react with a monomer of an acid to form its derivatives in a polymeric from. This adds to the cost of the process due to time involved and equipments and chemicals used in the process and such other factors.
In addition, it is observed by the inventor of present invention that when poly (acrylic acid) derivative of US Patent Application 0050241996 is used, (that is, ACUMER-1000 is used), heavy precipitation takes place, which can lead to fouling of the processing equipments. This is clear from the data provided in Table 6, Experiment No. 1 of the present specification. Also to prevent this precipitation higher dosages of the additive are required. The higher dosage will lead to higher cost. Other disadvantage of using additives having a tendency to precipitate is that it will be difficult to control the dosage at the desired level in the equipments in the field, such as crude desalter, and hence additive will have to be used always in excess.
US Patent Application 2005/0241997 Al describes different additives useful for enhancing phosphorous compound removal in refinery desalting process. Reactive phosphorus species can be removed or transferred from a hydrocarbon phase to a


water phase in an emulsion breaking process by using a composition that contains water-soluble hydroxy acids. Suitable water-soluble hydroxy acids include, but are not necessarily limited to glycolic acid, gluconic acid, C.sub.2-C.sub.4 alpha-hydroxy acids, poly hydroxy carboxylic acids, thioglycolic acid, chloro acetic acid, polymeric forms of the above hydroxyacids, poly-glycolic esters, glycolate ethers, and ammonium salt and alkali metal salts of these hydroxyacids, and mixtures thereof. The composition may optionally include a mineral acid to reduce the pH of the desalter wash water. A solvent may be optionally included in the composition. This US Patent Application permits transfer of reactive phosphorus species into the aqueous phase with little or no hydrocarbon phase undercarry into the aqueous phase. The composition is particularly useful in treating crude oil emulsions, and in removing calcium and other metals therefrom.
This US Patent Application 2005/0241997 Al, teaches the use of only hydroxyl mono - carboxylic acids such as, glycolic acid and polyhydroxy derivative thereof, like gluconic acid as an additive compound for removal of reactive phosphorous species, and calcium and other metals, from the hydrocarbon feedstock. However, the disadvantage of the use of these acids and derivatives as additives compound, as seen from the experiments conducted by the present inventor to remove calcium from calcium napthenate from hydrocarbon feedstock, is that these acids require higher dosages as additive compound since they are to be used in 2:1 molar ration with respect to calcium. When gluconic acid was used as additive compound by the present inventor, in the same molar ratio, that is, 2:1, very high dosage of gluconic acid is required.
The inventor of the present invention, after extensive experimentation, has surprisingly found that the use of any of the esters of various dicarboxylic acids such as monomethyl maleate, monomethyl oxylate, dimethyl maleate and ester of tricarboxylic acids such as citric acid and also esters of polycarboxylic acids is very effective in removal of metals like calcium and iron from hydrocarbon


feedstock. The prior art has never mentioned use of above mentioned esters for this purpose. It is surprisingly found by the present inventor that among all the esters of carboxylic acids, only a few do not lead to precipitation of calcium salt. For example, ester of maleic acid does not lead to any precipitation.
Thus it will be seen that the prior art mentions that the use of carboxylic acids is effective in removal of calcium from the hydrocarbon feedstock. However, the inventor of the present invention has surprisingly found that the use of esters of carboxylic acids is very effective in removal of calcium from the hydrocarbon feed stock.
In view of above, there is a need for developing a new method for the effective removal of metal contaminants, particularly calcium, from hydrocarbon feedstocks, including crude oil.
OBJECTS AND ADVANTAGES OF INVENTION
Accordingly, different objects and advantages of the present invention are described below.
An object of the present invention is to provide an economical method with increased efficiency due to lesser dosage of the chemical compounds used.
Another object of the present invention is to provide an efficient method to prevent precipitation of calcium salt in hydrocarbon phase or water phase, in use of some esters of carboxylic acids.
Still further objects and advantages of the present invention will become apparent from the ensuing detailed description of the invention.


DESCRIPTION OF DRAWINGS
A brief description of the accompanying drawings is given below:
Figure 1 shows, FTIR spectrum of naphthenic acid.
Figure 2 shows, FTIR spectrum of organic layer (oven dried) after reaction.
Figure 3 shows, FTIR spectrum of organic layer [Ca-naphthenate in toluene (oven
dried)] before reaction.
Figure 4 shows, FTIR spectrum of dried maleic anhydride in methanol and water
Figure 5 shows, FTIR spectrum of maleic acid
Figure 6 shows, FTIR spectrum of dried maleic anhydride in methanol
DETAILED DESCRIPTION OF INVENTION
In the method of the present invention, for removal of calcium from the hydrocarbon feedback, the additives comprising the following chemical compounds are used, which are esters of various dicarboxylic acids such as monomethyl maleate, monomethyl oxylate, dimethyl maleate and ester of tricarboxylic acids such as citric acid and also esters of polycarboxylic acids. According to the present invention, these esters are used to effectively remove calcium from the hydrocarbon phase, particularly from the calcium napthenate present in the hydrocarbon.
According to the most preferred embodiment of the present invention, the method of removal of calcium from the hydrocarbon feedstock, comprises the steps of:
(a) mixing the additive of the present invention, which is any one of the chemical compounds such as esters of various dicarboxylic acids such as monomethyl maleate, monomethyl oxalate, dimethyl maleate and ester of tricarboxylic acids such as citric acid and also esters of polycarboxylic acids or appropriate combination thereof in neat form or aqueous form or in solution with hydrocarbon, with any hydrocarbon feedstock stream such


as crude oil, containing metal and its salts, such as calcium naphthenate, in a crude desalter;
(b) permitting chemical reaction between the above mentioned additive and hydrocarbon feedstock;
(c) permitting formation of two phases, that is, aqueous phase and the hydrocarbon phase;
(d) separating the two phases of step (c) or permitting them separate.
According to another embodiment of the present invention, the method of removal of calcium from hydrocarbon feedstock, comprises the steps of:
(a) mixing the additive of the present invention, which is any one of the chemical compounds such as esters of various dicarboxylic acids such as monomethyl maleate, monomethyl oxalate, dimethyl maleate and ester of tricarboxylic acids such as citric acid and also esters of polycarboxylic acids or appropriate combination thereof in neat form or aqueous form or in solution with hydrocarbon, with any hydrocarbon feedstock stream such as crude oil, containing metal and its salts, such as calcium naphthenate, in a crude desalter;
(b) permitting chemical reaction between the above mentioned additive and hydrocarbon feedstock;
( c) feeding the reacted mixture to the crude desalter;
(d) permitting formation of two phases, that is, aqueous phase and the hydrocarboneous phase, in the crude desalter;
(e) separating the two phases of step (d) or permitting them to separate.
When the mixture is formed as per the step (a) in each of the above mentioned two methods, the metal ions are readily bound or chelated to carboxylic acid groups formed after hydrolysis of esters of the present invention in crude desalter


to form a complex. This metal- acid complex is ionic and water soluble, in few cases such as ester of maleic acid.
These two, phases, that is, the aqueous phase and the crude or hydrocarboneous phase, are separated or permitted to separate. As a result, the aqueous solution containing the metal contaminant is removed, thereby resulting in a hydrocarbon feed with metals already removed from it, which then can be handled in the same manner as any other carboneous feed and processed by conventional hydroprocessing techniques.
It is contemplated in the most preferred embodiment that the physical separation process is ordinarily to be done in a conventional crude desalter, which is usually used for desalting pretroleum crudes before they are hydroprocessed. This separation is to be done by any separation process, however, and also includes countercurrent extraction.
The contact time between the aqueous extraction solution and the hydrocarboneous feed during mixing action is important and varies from between less than few seconds to about six hours. The preferred contact time is from about 5 seconds to about 2 hours.
Preferably, the chemical compounds mentioned in step (a) above, are injected into the desalter wash water prior to blending of this wash water with the incoming crude oil. This mixture is then passed through a high shear valve to obtain through contact of the water with the crude oil. This process is called "desalting" and is literally removing water soluble chloride salts from the oil. The chloride salts are present due to the water found in the incoming crude oil. Essentially, the salt concentration is diluted by the addition of the wash water. The wash water is treated with dimulsifiers to help the oil/water separation. Any water remaining


with oil effluent from the desalter will have low salt values. Temperatures in the desalter typically range from about 93 °C to about 163 °C.
To remove metals such as calcium in the desalter, the chemical compounds mentioned in step (a) above are added continuously to the wash water. With the vigorous mixing of the oil and water, the acids formed after hydrolysis of the chemical compound, chelate the calcium. This complex formed with the calcium is water soluble, hence the calcium is removed via the water phase.
The dosage of each of the above mentioned chemical compounds and the combinations thereof, generally ranges from about 0.001 to 5 weight percent in the desalter wash water. The present invention can be used in molar, submolar or excess molar concentrations with respect to metals in the hydrocarbon stream such as calcium or its salts such as calcium napthenate.
The advantages of the use of the additives of the present invention in calcium removal are explained below in details.
The additive of the present invention in its original form as ester, is in liquid form, whereas the respective acids from which corresponding esters are made are in solid form. Generally, the acids do not have high solubility in water. Whenever a solution of an acid in water is made, it has high pour point as it freezes in cold conditions. In its frozen form, pumping is not feasible, which poses serious handling difficulties. Many times, heating facilities are not available in storage area. In addition, heating is not a preferable option for maleic acid, as it is known that when maleic acid aqueous solution is exposed to temperature above 45°C, it will get converted into fumaric acid, which has extremely low solubility in water. It is also difficult to maintain temperature at 45°C or below in storage area, because generally steam is used as a heating source, which will have temperature above 100°C. Due to its low solubility, the fumaric acid gets precipitated and clogs the pipe lines.


The ester additives of present invention do not freeze upto -27°C temperature. Hence it can then be used in cold conditions without resorting to heating.
The Calcium - removal - effects of the ester additives of present invention are comparable to results obtained by using corresponding acids for removal of calcium.
The ester additives of present invention are soluble in hydrocarbon feedstock stream, whereas corresponding acids are insoluble in hydrocarbon feedstock streams. Hence the additives of present invention can be used in solution with hydrocarbon instead of using them in aqueous solution. This solution with hydrocarbon can be fed to the hydrocarbon feedstock stream in the crude desalter.
As the ester additives of the present invention are soluble in hydrocarbon, the additives can be added to hydrocarbon feedstock in storage area, giving the advantage of more contact time of additive with the hydrocarbon.
If the ester additive of the present invention is added to hydrocarbon feedstock invention is added to hydrocarbon feedstock which is in stored condition, which is then supplied to crude desalter, the pH of the system in crude desalter will not dip, thereby preventing acidic condition and hence preventing corrosion of equipments.
The ester additive of the present invention, being in liquid form, can be used without any solvent, that is, it can be used neat, therby effecting savings in cost of transportation.
The foregoing may be better understood by reference to the following examples, which are presented for the purposes of illustration and are not intented to limit the scope of the invention.


GENERAL POINTS ABOUT THE EXAMPLES
1. The details of the quantities of Calcium-naphthenate in toluene having an amount of calcium of 1957 ppm in the hydrocarbon layer and demineralised water, used in each of the experiments given below, are given in Table - 2.
2. The Calcium naphthenate was prepared by reaction of sodium salt of naphthenic acid (2 moles ) and calcium chloride (l mole). The product was washed to remove sodium chloride. The napthenic acid used had an acid value of approximately 226mg KOH/ gm. The resulting calcium naphthenate had approximately 7.5% of calcium. This was dissolved in toluene to get an approximately 1957 ppm of calcium. The FTIR spectras of Naphthenic Acid, and Calcium Naphthenate are shown in the figure 1 and 3 respectively .
3. FTIR spectrum figures are given only for Example 1. For other examples, only the observational results are specified in Table 2.
4. The mole ratio of calcium to additive compound is also given in Table 2. Actual weight of additive compound is also mentioned in Table 2. If the additive is in solution form, the weight of active ingredient is given in Table 2.
5. Generally, results given in Table 2 , for each additive compound represents average of three experiments.
6. Results presented in Table 2 are obtained after 15 minutes for reaction at 115 degree centigrade.
Generally the Calcium content in aqueous phase was measured using Ion Chromatographic technique (IC) and by Inductive coupled plasma for the hydrocarbon phase.


EXAMPLE -1
TEST METHOD AND RESULTS FOR USE OF ADDITIVES
Procedure: Additive of the present invention, demineralized water and Ca-naphthenate in toluene were charged into a stainless steel autoclave and was reacted at 115°C for 15 minutes. After 15 minutes it was cooled to room temperature and the contents of the round bottom flask were poured into a separating funnel. Two separated layers that is top hydrocarboneous layer and bottom aqueous were collected and analyzed as mentioned below. The aqueous layer was analysed for pH, and Calcium content was analysed by using Ion Chromotography. The hydrocarboneous layer was dried to remove toluene and the dried sample was analysed by Fourier Transform Infrared Spectrometer (FTIR) as discussed below, and for Calcium content by using ICP technique (INDUCTIVE COUPLED PLASMA) and also for acid value. The results are given in details below and in Table 2.
In all of the examples, the mole ratio of Ca-naphthenate to additive is 1:1, and the Calcium content of Ca-naphthenate solution in toluene used for these examples is 1957 ppm
Analysis: FTIR data:
FTIR spectrum of naturally occurring free naphthenic acid shown in fig. 1 shows a characteristic peak at about 1700 cm-1 due to the presence of carboxylic acid (COOH) group. The acid value of the free acid is about 227 mg / KOH.
The FTIR spectrum of calcium napthenate shows a characteristic peak at about 1541 cm-1 as shown in fig.3.
After completion of 15 minutes of reaction of Ca-naphthenate solution in toluene with additives of present invention, it was observed, as shown in figure 2, that the toluene free hydrocarboneous layer showed the characteristic peak at about 1698 cm-1 indicating the presence of free carboxylic acid group (similar to fig 1) such


as free napthenic acid in the hydrocarboneous phase. The complete absence of 1541 cm -1 peak of calcium napthenate in figure 2 indicates that the additives are very effective in extracting into the water phase, the Calcium from calcium napthenate which was present in the hydrocarbon feed. The acid value of the dried hydrocarbon layer was also estimated and shown in Table 2. It should be noted that the additive which do not remove calcium from calcium naphthenate, does not show any peck at 1698 cm-1.
Ca content data:
The effectiveness of the present invention is further proved by measuring the Calcium content in aqueous layer after reaction. The magnitude of calcium removed in the aqueous phase is shown in Table 2. It can be seen that the efficiency of calcium removal is greater than 90%. This is another evidence of high effectiveness of additives of the present invention in causing complete removal of bound calcium in calcium napthenate which was present in the hydrocarbon feed, and extraction of this calcium into the water pahse.
pH values data:
Before reaction, pH of the aqueous layer was about 2 to 3 due to presence of additive in the aqueous phase and after reaction pH of the aqueous phase was found to be 6 to 9, thereby indicating that conversion of additive into its calcium salt thereby indicating effective extraction into the water phase of calcium from calcium napthenate. At this pH value the aqueous phase is non corrosive and this aqueous phase is clear and free of any precipitate at the bottom for few additives, for example, maleic esters. Details are mentioned in Table 2. This is the additional advantage of the present invention.


EXMAPLE 2
Preparation of Methanolic solution of additive of present invention
In the preparation of methanolic solution of the additive of the present invention, the following steps were used:
(a) To a clean four - necked round bottom flask, equipped with thermometer, stirrer, and inlet for nitrogen, 30 gm of methanol was charged.
(b) Total of 33 gm of maleic anhydride was added into the above mentioned flask, in six lots;
(c) The mixture was stirred well till a clear solution was obtained, indicating formation of maleic ester;
(d) 37 gms of water was dded to the clear solution;
(e) The exotherm of approximately 5°C to 10°C was noted;
(f) The mixture was mixed well;
(g) The mixture was analyzed for acid value which was found to be 225 mg / KOH; it was observed that the acid value drops on storage of the mixture. For example, the acid value was 196 mg / KOH after storing for 17 days and was 145 mg / KOH after storing for one year.
(h) The final product obtained after drying, is found to be in liquid form.
(i) The formation of ester is confirmed by FTIR due to presence of a peck at 1725 cm-1 in Figure 4. It can be seen that Figure 5 which is FTIR spectrum of pure maleic acid is different from the Figure 4.
The advantage of the present invention can be seen from the fact that the pour point of the solution was below - 30°C and the material did not freeze at - 27°C even after keeping for 20 days.


The above mentioned procedure was followed in experiments conducted for use of oxalic acid and also for citric acid in corresponding step (b). The results showing efficiency of calcium-removal for above mentioned three chemicals are shown in Table 2. The results of these experiments, showing details of effect of storage of methanolic solution of additive of present invention showing drop in acid value and absence of solidification due to storage at extremely low temperature are given in Table 3. The experiments were repeated for above -mentioned steps, except addition of methanol in step (a), just for obtaining comparative results, which are shown in Table 3.
EXMAPLE 2
Preparation of Maleic Ester used in present invention
In this preparation of maleic ester which is one of the additives of the present invention, the following steps were used:
(a) To a clean four - necked round bottom flask, equipped with thermometer, stirrer, and inlet for nitrogen, 30 gm of methanol was charged.
(b) Total of 33 gm of malic anhydride was added in to the above mentioned flask, in six lots;
(c) The mixture was stirred well till a clear solution was obtained, indicating formation of maleic ester;
(d) The acid value of the solution was 159 mg / KOH.
The formation of ester is confirmed by FTIR due to presence of a peck at 1725 cm-1 in Figure 6.


Details of calcium naphthenate solution in toluene and aqueous solution with additive used in the experiments.
The details of calcium napthenate solution in toluene and aqueous solution with additive used in the experiments carried out by the inventor are given in Table 1.
Table-1:

Sr. No. Name of the raw materials used Wt.%
1. Calcium-naphthenate in toluene having an amount of calcium of 2247 ppm in the hydrocarbon layer 50%
2. Aqueous solution having additive of present inventions 50%


Table-2:

Documents:

166-MUM-2008-ABSTRACT(23-1-2009).pdf

166-MUM-2008-ABSTRACT(4-1-2013).pdf

166-MUM-2008-AUSTRALIAN DOCUMENT(13-7-2012).pdf

166-MUM-2008-AUSTRALIAN DOCUMENT(4-1-2012).pdf

166-MUM-2008-CANADA DOCUMENT(13-7-2012).pdf

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166-MUM-2008-CLAIMS(23-1-2009).pdf

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166-MUM-2008-CORRESPONDENCE(22-10-2009).pdf

166-MUM-2008-CORRESPONDENCE(23-1-2009).pdf

166-MUM-2008-CORRESPONDENCE(4-1-2013).pdf

166-MUM-2008-CORRESPONDENCE(7-1-2010).pdf

166-MUM-2008-CORRESPONDENCE(7-1-2013).pdf

166-mum-2008-correspondence-received.pdf

166-mum-2008-description (provisional).pdf

166-MUM-2008-DESCRIPTION(COMPLETE)-(23-1-2009).pdf

166-MUM-2008-DRAWING(23-1-2009).pdf

166-mum-2008-drawings.pdf

166-MUM-2008-EP DOCUMENT(13-7-2012).pdf

166-MUM-2008-FORM 1(4-1-2013).pdf

166-MUM-2008-FORM 13(4-1-2013).pdf

166-MUM-2008-FORM 18(22-10-2009).pdf

166-mum-2008-form 2(23-1-2009).pdf

166-MUM-2008-FORM 2(TITLE PAGE)-(23-1-2009).pdf

166-MUM-2008-FORM 2(TITLE PAGE)-(4-1-2013).pdf

166-MUM-2008-FORM 2(TITLE PAGE)-(PROVISIONAL)-(24-1-2008).pdf

166-MUM-2008-FORM 26(7-1-2013).pdf

166-MUM-2008-FORM 3(13-7-2012).pdf

166-MUM-2008-FORM 3(23-1-2009).pdf

166-MUM-2008-FORM 3(7-1-2010).pdf

166-MUM-2008-FORM 5(23-1-2009).pdf

166-mum-2008-form-1.pdf

166-mum-2008-form-2.doc

166-mum-2008-form-2.pdf

166-mum-2008-form-26.pdf

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166-MUM-2008-PETITION UNDER RULE 137(13-7-2012).pdf

166-MUM-2008-REPLY TO EXAMINATION REPORT(13-7-2012).pdf

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166-MUM-2008-SINGAPORE DOCUMENT(13-7-2012).pdf

166-MUM-2008-SINGAPORE DOCUMENT(4-1-2012).pdf

166-MUM-2008-SPECIFICATION(AMENDED)-(4-1-2013).pdf

166-MUM-2008-US DOCUMENT(13-7-2012).pdf

166-MUM-2008-US DOCUMENT(4-1-2012).pdf


Patent Number 256905
Indian Patent Application Number 166/MUM/2008
PG Journal Number 33/2013
Publication Date 16-Aug-2013
Grant Date 08-Aug-2013
Date of Filing 24-Jan-2008
Name of Patentee DORF KETAL CHEMICALS (I) PVT. LTD
Applicant Address DORF KETAL TOWERS, D'MONTE STREET, ORLEM, MALAD (W), MUMBAI
Inventors:
# Inventor's Name Inventor's Address
1 SUBRAMANIYAM MAHESH DORF KETAL TOWERS, D'MONTE STREET, ORLEM, MALAD (W), MUMBAI-400064
PCT International Classification Number C10G17/02;C10G17/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA