An ethoxylated cardanol sulphonic acid and a method of preparing it

Abstract

An ethoxylated cardanol sulphonic acid represented by Formula I is disclosed. (I) wherein: n = 7-20; R = H or SO3H. Also are disclosed, formulations comprising and a process for preparing said ethoxylated cardanol sulphonic acid.

Description

[0001] AN ETHOXYLATED CARD ANOL SULPHONIC ACID AND A METHOD

[0002] OF PREPARING IT

[0003] FIELD OF INVENTION

[0004] The present disclosure relates to novel cardanol based surfactants. More particularly, it relates to an ethoxylated cardanol sulphonic acid, method of preparing it, compositions or formulations comprising it and its applications.

[0005] BACKGROUND

[0006] Surfactants are versatile chemical compounds, which are widely used as detergents, wetting agents, emulsifiers, foaming agents, solubilizers, and dispersants in pharmaceutical, personal care, cosmetic, food, and cleaning compositions.

[0007] In 2023, the global surfactants market size was estimated to be USD 45.18 billion and was projected to grow from USD 47.36 billion in 2024 to USD 70.13 billion by 2032 at a CAGR of 4.9% (Fortune Business Insights, Report ID: FBI102385).

[0008] The global crisis of petroleum resources has contributed to an increase in the cost of raw materials and fine chemicals. Further, the extensive use of traditional surfactants has raised health and ecological concerns due to their toxic effect and degradability issues. The consumers have also become sensitive to the origin of the products they buy and their impact on the health and environment. Therefore, there is an increasing demand for sustainable and eco-friendly products. Accordingly, considerable efforts are being made to obtain fine chemicals from natural and renewable materials. SUMMARY

[0009] The present disclosure relates to an ethoxylated cardanol sulphonic acid, which is represented by Formula I:

[0010] Formula I wherein: n = 7-20

[0011] R = H or SO3H

[0012] The present disclosure also relates to a process for preparing said ethoxylated cardanol sulphonic acid. The process comprises reacting 1 mol of an ethoxylated cardanol oil with about 0.8-2.0 mol of a sulfonating agent at a temperature in the range of 10-130°C to obtain the ethoxylated cardanol sulphonic acid.

[0013] BRIEF DESCRIPTION OF DRAWINGS

[0014] FIG. 1 is a graphical representation of variation in surface tension with concentration of the Ethoxylated Cardanol Sulphonic Acid (‘ECSA’) in accordance with an embodiment of the present disclosure.

[0015] FIG. 2 is a Fourier Transform Infrared (‘FTIR’) spectrum of the ECSA in accordance with an embodiment of the present disclosure.

[0016] FIG. 3 is a High-Performance Liquid Chromatography (‘HPLC’) data of the ECSA in accordance with an embodiment of the present disclosure. FIG. 4 is a graphical representation of biodegradability test ‘OECD 301B’ on the ECSA in accordance with an embodiment of the present disclosure.

[0017] FIG. 5 is a combined mean A+O scores of skin irritation test ‘IS 13424 : 2001’ on the ECSA in accordance with an embodiment of the present disclosure.

[0018] DETAILED DESCRIPTION

[0019] Reference will now be made in detail to embodiments of the present disclosure. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive manner, simply because it is being utilized in conjunction with a detailed description of certain specific embodiments of the invention. Furthermore, embodiments of the invention may include several features, no single one of which is solely responsible for its desirable attributes, or which is essential to practicing the inventions herein described.

[0020] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are explanatory of the invention and are not intended to be restrictive thereof.

[0021] The terms “a,” “an,”, and “the” are used to refer to “one or more” (i.e., to at least one) of the grammatical object of the article.

[0022] Reference throughout this specification to “an aspect”, “another aspect” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention.

[0023] The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion and are not intended to be construed as “consists of only”, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such process or method.

[0024] Likewise, the terms “having” and “including”, and their grammatical variants are intended to be non-limiting, such that recitations of said items in a list are not to the exclusion of other items that can be substituted or added to the listed items.

[0025] Also, any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of " 1 to 10" is intended to include any and all subranges between and including the recited minimum value of 1 and the recited maximum value of 10, that is, all subranges beginning with a minimum value equal to or greater than 1 and ending with a maximum value equal to or less than 10, and all subranges in between.

[0026] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described.

[0027] The term “cardanol” refers to the phenolic lipid synthesized from anacardic acid, and represented by the following Formula: wherein n = 0, 2, 4, or 6.

[0028] The present disclosure relates to cardanol based surfactants. Specifically, the disclosure relates to an Ethoxylated Cardanol Sulphonic Acid (‘ECSA’). The ECSA according to the present disclosure is represented by Formula I:

[0029] Formula I wherein: n = 7-20

[0030] R = H or SO3H

[0031] In accordance with some embodiments, n is 9-15. In an embodiment, n is 12.

[0032] The ECSA has a pH in the range of 1-4 in 1% aqueous solution. In accordance with some embodiments, the pH is in the range of 2.0-3.0 in 1% aqueous solution.

[0033] The ECSA has a surface tension in the range of 35-50 N / m in 1% aqueous solution. In some embodiments, the surface tension is in the range of 40-50 N / m. The ECSA has a viscosity in the range of 2500-15000 cps at room temperature. In some embodiments, the viscosity is in the range of 2600-8000 cps.

[0034] The ECSA has a Hydrophilic-Lipophilic Balance (‘HLB’) value in the range of 12-15, when calculated theoretically.

[0035] The ECSA may be almost or completely soluble in water. In accordance with an embodiment, when incorporated in a formulation such as a detergent formulation or a cleaning formulation, it may not interfere with color of the formulation.

[0036] The present disclosure also relates to compositions or formulations comprising the ECSA.

[0037] In accordance with various embodiments, the formulation comprises the ECSA in the range of 0.5-50 wt%.

[0038] The formulation may be any suitable form such as a granule, a powder, a gel, or a liquid. It may also be in formulated as a unit doses, for example, as tablets or capsules. The formulation may be used for cleaning or washing textile or nontextile surfaces such as stone, metal or wood.

[0039] The formulation includes one or more additional components. The choice of the additional components would depend on various factors such as the form of formulation, for example, whether the formulation is in the form of liquid or powder and performance required. Examples of such additional components include but are not limited to an anionic surfactant, a non-ionic surfactant, a secondary surfactant, a builder, an alkali agent, a salt, an anti-redeposition additive, a chelating agent, an optical brightener, an enzyme, a free flow agent, a buffering agent, a colour, a preservative, a fragrance, a filler, a dispersion agent, a stabilizer, water, and combinations thereof. In some embodiments, the formulation comprises 0.5-20 wt% of the anionic surfactant. In some embodiments, the anionic surfactant includes a combination of two or more anionic surfactants. The anionic surfactant can be any suitable anionic surfactant. Examples of the suitable anionic surfactant include but are not limited to sodium lauryl sulphate, alpha olefin sulphonate, methyl ester sulfonate, and combinations thereof.

[0040] In some embodiments, the formulation comprises 20-30 wt% of the builder. In some embodiments, the builder includes a combination of two or more builders. The builder can be any suitable builder. Examples of the suitable builder include but are not limited to sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium tripolyphosphates, zeolite, and combinations thereof.

[0041] In some embodiments, the formulation comprises 30-40 wt% of the salt. In some embodiments, the salt includes a combination of two or more salts. The salt can be any suitable salt. Examples of the suitable salt include but are not limited to sodium chloride, sodium sulphate, potassium chloride, potassium sulphate, and combinations thereof.

[0042] In various embodiments, the formulation comprises 0.5-5 wt% of the alkali agent. In some embodiments, the alkali agent includes a combination of two or more alkali agents. The alkali agent can be any suitable alkali agent. Examples of the suitable alkali agent include but are not limited sodium orthosilicate, sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, and combinations thereof.

[0043] In some embodiments, the formulation comprises 0.5-2.0 wt% of the antiredeposition additive. In some embodiments, the anti-redeposition additive includes a combination of two or more anti-redeposition additives. The antiredeposition additive can be any suitable anti-redeposition additive. Examples of the suitable anti -redeposition additive include but are not limited to sodium carboxymethyl cellulose, hydroxypropyl methylcellulose, polyacrylate, acrylic / maleic co-polymer, sodium polyacrylate, and combinations thereof.

[0044] In some embodiments, the formulation comprises 0.01-0.5 wt% of the chelating agent. In some embodiments, the chelating agent include a combination of two or more chelating agents. The chelating agent can be any suitable chelating agent. Example of the suitable chelating agent include but are not limited to disodium ethylenediamine tetraacetic acid, tetrasodium ethylenediamine tetraacetic acid, sodium gluconate, sodium phosphate, and combinations thereof.

[0045] In some embodiments, the formulation comprises 0.005-0.2 wt% of the optical brightener. In some embodiments, the optical brightener includes a combination of two or more optical brighteners. The optical brightener can be any suitable optical brightener. Examples of the suitable optical brightener include but are not limited to Tinopal®, disodium distearyl biphenyl disulfonate compound, and combinations thereof.

[0046] In some embodiments, the formulation comprises 1-3 wt% of the free flow agent. In some embodiments, the free flow agent includes a combination of two or more free flow agents. The free flow agent can by any suitable free flow agent. Examples of the suitable free flow agent include but are not limited to silica, sodium aluminosilicate, and combinations thereof

[0047] In some embodiments, the formulation comprises 1-5 wt% of the buffering agent. In some embodiments, the buffering agents includes a combination of two or more buffering agents. The buffering agent can be any suitable buffering agent. Examples of the suitable buffering agent include but are not limited to sodium bicarbonate, potassium bicarbonate, sodium hydroxide, and combinations thereof. In some embodiments, the formulation comprises 10-28 wt% of the filler. In some embodiments, the filler includes a combination of two or more fillers. The filler can be any suitable filler. Examples of the suitable filler include but are not limited to dolomite, calcium carbonate, sodium sulphate, and combinations thereof.

[0048] In some embodiments, the formulation comprises 0.01-0.3 wt% of the colour. In some embodiments, the colour include a combination of two or more colors.

[0049] In some embodiments, the formulation comprises 0.1-3 wt% of the preservative. In some embodiments, the preservative includes a combination of two or more preservatives.

[0050] In some embodiments, the formulation comprises 0.1-5 wt% of the enzyme. In some embodiments, the enzyme includes a combination of two or more enzymes. The enzyme can be any suitable enzyme. Examples of the suitable enzymes include but are not limited to protease, amylase, cellulose, lipase, and combinations thereof.

[0051] In some embodiments, the formulation comprises 0.1-1 wt% of the fragrance. In some embodiments, the fragrance includes a combination of two or more fragrances.

[0052] In some embodiments, the formulation comprises 60-90 wt% of water.

[0053] The present disclosure also relates to a hydrogenated EC SA and compositions or formulation comprising said hydrogenated ECSA.

[0054] The present disclosure also relates to a process for preparing the disclosed ECSA. The reaction scheme of the process comprises:

[0055] The process comprises reacting about 1 mol of an ethoxylated cardanol oil with about 0.8-2.0 mol of a sulfonating agent at a temperature in the range of 10-130°C to obtain the ECSA.

[0056] In some embodiments, about 1 mol of the ethoxylated cardanol oil is reacted with about 0.9-1.25 mol of the sulfonating agent.

[0057] In some embodiments, the ethoxylated cardanol oil is reacted with the sulfonating agent at a temperature in the range of 25-120°C.

[0058] The ethoxylated cardanol oil may be obtained from commercial sources. In some embodiments, the ethoxylated cardanol oil may be obtained by reacting about 1 mol of cardanol oil with about 7-20 mol of ethylene oxide at a temperature in the range of 140-170°C. In some embodiments, about 1 mol of the cardanol oil is reacted with about 9-15 mol of ethylene oxide to obtain the ethoxylated cardanol oil. In some embodiments, the cardanol oil is reacted with ethylene oxide at a temperature in the range of 150-160°C.

[0059] The moles recited herein are not intended to limit the scope and meaning of the disclosure. For example, a person skilled in the art will understand that changing the moles of the ethoxylated cardanol oil from 1 mole to any other moles will accordingly vary the moles of the sulfonating agent in the same ratio as given above. Any suitable sulfonating agent may be used in the disclosed process. Examples of the suitable sulfonating agent include but are not limited to sulphuric acid, oleum, SO3 gas, chlorosulphonic acid, and combinations thereof. In an embodiment, the sulfonating agent is sulphuric acid.

[0060] The invention will now be described with respect to the following examples, which do not limit the disclosed method in any way and only exemplify the claimed method. It will be apparent to those skilled in the art that various modifications and variations can be made to the method / process of the present disclosure without departing from the scope of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the method / process disclosed herein.

[0061] EXAMPLES

[0062] Example 1: Preparation of the ECSA in accordance with an embodiment of the present disclosure

[0063] 1 kg of ethoxylated cardanol oil was taken into a reaction vessel having a heater with a temperature controller, a water condenser and stirring arrangements. 0.100-0.300 kg of concentrated sulphuric acid was taken in another vessel. Addition of sulphuric acid to the ethoxylated cardanol oil was started at 25°C, and the addition was completed within 30-40 minutes while controlling exotherm below 65°C under a constant stirring. Thereafter, the reaction was continued for next up to 4 hours with a constant stirring at 25°C-120°C. The reaction was monitored using HPLC. After completion of the reaction, the reaction mass was cooled to room temperature. The ECSA was obtained with 100% yield.

[0064] Example 2: Effect of degree of ethoxylation on solubility of the ECSA prepared in accordance with various embodiments of the present disclosure The effect of the degree of ethoxylation i.e. number of Ethylene Oxide (EO) units present on the ECSA, on solubility of the ECSA in water, was studied. 50 gm of each of the ethoxylated cardanol oil with varying degree of ethoxylation was mixed with 6.67 - 10.04 gm of concentrated sulphuric acid. The mixture was allowed to react for 3 hours at 55°C. The resultant ECSA so obtained was mixed with 5000 ml of water for 1 hour at 55°C. The results are provided in Table 1.

[0065] Table 1: Effect of Degree of Ethoxylation on Solubility of the ECSA in Water Example 3: Effect of concentrated sulphuric acid ratio on the conversion of the ethoxylated cardanol oil to the ECSA in accordance with various embodiments of the present disclosure

[0066] Sulfonation reaction was carried out using concentrated sulphuric acid as a sulfonating agent at a reaction temperature of 55°C. The ratio of sulphuric acid was varied. The details of the process and the results are provided in Table 2.

[0067] Table 2: Effect of the concentrated Sulphuric Acid ratio on the conversion of the Ethoxylated Cardanol Oil to the ECSA

[0068] Example 4: Preparation of the ECSA with 12 EO units (‘12 EO ECSA’) at 30°C in accordance with an embodiment of the present disclosure

[0069] 50 gm of the ethoxylated cardanol oil with an average of 12 EO units was taken into a reaction vessel having a heater with a temperature controller, a water condenser and stirring arrangements. 9 gm of concentrated sulphuric acid was taken in another vessel. Addition of sulphuric acid to the ethoxylated cardanol oil was started at 25°C. The addition was completed within 30-40 minutes while controlling exotherm below 40°C under a constant stirring. Thereafter, the reaction was continued for next 3 hours with a constant stirring at 30°C temperature. The reaction was monitored using HPLC. After 3 hours the reaction mass was cooled to room temperature and the 12 EO ECSA was obtained.

[0070] Example 5: Preparation of 12 EO ECSA at 50°C in accordance with an embodiment of the present disclosure

[0071] 50 gm of the ethoxylated cardanol oil with an average of 12 EO units was taken into a reaction vessel having a heater with a temperature controller, a water condenser and stirring arrangements. 9 gm of concentrated sulphuric acid was taken in another vessel. Addition of sulphuric acid to the ethoxylated cardanol oil started at 25°C. The addition was completed within 30-40 minutes while controlling exotherm below 50°C under a constant stirring. Thereafter, the reaction was continued for next 3 hours with a constant stirring at 50°C. The reaction was monitored using HPLC. After 3 hours the reaction mass was cooled to room temperature and the 12 EO ECSA was obtained. Example 6: Preparation of 12 EO ECSA at 120°C in accordance with an embodiment of the present disclosure

[0072] 50 gm of the ethoxylated cardanol oil with an average of 12 EO units was taken into a reaction vessel having a heater with a temperature controller, a water condenser and stirring arrangements. 9 gm of concentrated sulphuric acid was taken in another vessel. Addition of sulphuric acid to the ethoxylated cardanol oil started at 25°C. The addition was completed within 30-40 minutes while controlling exotherm below 50°C under a constant stirring. Thereafter, the reaction was continued for next 3 hours with a constant stirring at 120°C. The reaction was monitored using HPLC. After 3 hours the reaction mass was cooled to room temperature and the 12 EO ECSA was obtained.

[0073] Example 7: Effect of reaction temperature on conversion of the ethoxylated cardanol oil, surface tension and viscosity of 12 EO ECSA

[0074] The effect of reaction temperature on the conversion of ethoxylated cardanol oil to the 12 EO ECSA, the surface tension and the viscosity (at 30°C, Spindle No 6) of the 12 EO ECSA prepared above was studied. The results are provided in Table 3.

[0075] Table 3: Effect of Reaction Temperature Example 8: Preparation of 12 EO ECSA at 60°C in accordance with an embodiment of the present disclosure

[0076] 1.0 kg of the ethoxylated cardanol oil with average 12 EO units was taken into a reaction vessel having a heater with a temperature controller, a water condenser and stirring arrangements. 0.150 kg of concentrated sulphuric acid was taken in another vessel. Addition of the sulphuric acid to ethoxylated cardanol oil started at 25°C. The addition was completed within 30-40 minutes while controlling exotherm below 60°C under a constant stirring. Thereafter, the reaction was continued for next 1-3 hours with a constant stirring at 60°C. The reaction was monitored using HPLC. After 3 hour the reaction mass was cooled to room temperature and the 12 EO ECSA was obtained.

[0077] Example 9: Preparation of 12 EO ECSA at 60°C in accordance with an embodiment of the present disclosure

[0078] 1.0 kg of the ethoxylated cardanol oil with an average of 12 EO units was taken into a reaction vessel having a heater with a temperature controller, a water condenser and stirring arrangements. 0.107 kg of concentrated sulphuric acid was taken in another vessel. Addition of sulphuric acid to the ethoxylated cardanol oil was started at 25°C. The addition was completed within 30-40 minutes while controlling exotherm below 50°C under a constant stirring. Thereafter, the reaction was continued for next 10 hours with a constant stirring at 60°C. The reaction was monitored using HPLC. After achieving conversion more than 90%, reaction mass was cooled to room temperature and the 12 EO ECSA was obtained. The viscosity of product was observed 2600 cps at 30°C.

[0079] Example 10: Effect of sulphuric acid ratio at > ~ 90% conversion of ethoxylated cardanol oil on the viscosity in accordance with various embodiments of the present disclosure Sulfonation reaction was carried out using concentrated sulphuric acid as the sulfonating agent at a reaction temperature of 55°C. The concentration of sulphuric acid was varied. The details of the process and the results are provided in Table 4.

[0080] Table 4: Viscosity effect

[0081] Example 11: Characterization of the 12 EO ECSA obtained in Example 9 Surface tension at different concentrations: Surface tension of the 12 EO ECSA obtained in Example 9 was measured at different concentrations in water using Biolin Scientific™ Instrument (Attention Theta Flex model). The results are provided in Table 5.

[0082] Table 5: Surface Tension at Different Concentrations of the 12 EO ECSA of

[0083] Example 9

[0084] Critical Micelle Concentration (‘CMC’): CMC of the 12 EO ECSA was calculated on the basis surface tension measured at different concentrations as shown in FIG. 1. The CMC value of product was ~80 gm / 1.

[0085] Foaming characteristics: The foam height and foam retention were evaluated using 0.25% aq. solution of the 12 EO ECSA in water at different time interval. 50 ml solution was taken in a measuring cylinder of 250 ml capacity. The cylinder was tilted up and down 10 times. The foam height was observed to be about 50 mm.

[0086] Hydrophilic lipophilic balance (HLB) value: The HLB value was theoretically calculated as per the following formula:

[0087] HLB value = 20 x (Mh / M) where,

[0088] Mh = molecular weight of hydrophilic group

[0089] M = Molecular weight of whole molecule

[0090] The HLB value was found to be 12-15.

[0091] FTIR data: FIG. 2 depicts the FTIR spectra of the 12 EO ECSA. Peak at 1050 and 590 cm'1confirmed the sulfonation on aromatic ring (C-SO3H). Peak at 526- 545 cm'1confirmed the aliphatic C-S bond formed by sulfonation on hydroxy group. Certificate of Analysis (‘COA’).: The COA details are provided in Table 6.

[0092] Table 6: COA Details HPLC data: HPLC analysis was performed on Shimadzu UFLC HPLC System with C18 ZORBAX Eclipse XDB HPLC column. Acetonitrile:water (80:20) was used as a mobile phase. Key raw material retention time was ~9.8 minutes. The conversion was calculated based on 9.8 minutes retention time peak area reduction. At reaction temperature 55-65°C conversion was -90%. Reverse phase HPLC analysis was conducted on Cl 8 Zorbax eclipse XDB column with C18 ZORBAX Eclipse XDB HPLC column. Detector was diode array detector at 270 nm. The flow rate was 1.8 ml / minute. Acetonitrile: water (80:20) was used as a mobile phase. The column temperature was 40°C and the run time was 40 minutes. It was observed that -94% conversion of the ethoxylated cardanol oil was attained at 60°C as depicted in Table 7 and FIG. 3. Table 7: Conversion of the Ethoxylated Cardanol Oil

[0093] Example 12: Preparation of the hydrogenated 12 EO ECSA in accordance with an embodiment of the present disclosure

[0094] Reaction Scheme

[0095] 50 gm of the hydrogenated ethoxylated cardanol oil was taken into a reaction vessel having a heater with a temperature controller, a water condenser and stirring arrangements. 9 gm of concentrated sulphuric acid was taken in another vessel. Addition of sulphuric acid to the hydrogenated ethoxylated cardanol oil was started at 25°C. The addition was completed within 30-40 minutes while controlling exotherm below 50°C under a constant stirring. Thereafter, the reaction was continued for next 3 hours with a constant stirring at 120°C. The reaction was monitored using HPLC. After 3 hours, the reaction mass was cooled to room temperature and the hydrogenated 12 EO ECSA was obtained. Example 13: Preparation of the detergent formulation in accordance with and embodiment of the present disclosure

[0096] Sodium carbonate and sodium chloride were charged in a ribbon blender to obtain a mixture. The 12 EO EC SA obtained in Example 9 was added slowly to the mixture and mixed until neutralization was completed. The remaining ingredients as shown in Table 8 were added and mixed thoroughly. It was ensured that no lumps were formed. The formulations were packed in suitable packaging. Table 8: Different Detergent Formulations

[0097] Example 14: Performance evaluation of the detergent formulations obtained in Example 13. Method: IS 4955:2001 method was used to evaluate the performance of the detergent formulation of Example 13. Cloth samples were artificially soiled with various substances as shown in Table 9. The soil or stains were removed by washing the cloth samples with a solution of the detergent formulation to be evaluated under standard conditions. The reflectance of the unsoiled, soiled and washed cloth samples was measured instrumentally using a standard spectrophotometer. The detergency was expressed as a percentage of the soil removed.

[0098] Instruments and Materials: Hunterlab’s LabScan® XE spectrophotometer, Tergotometer (Spear Exim Pvt. Ltd.), calcium chloride, magnesium sulphate, hardness testing meter, standard soiled cloth samples (5 cm x 5 cm)- from Center for Testmaterials (‘CFT’) Netherland, and deionised water.

[0099] Preparation of hard water: Desired quantity of demineralized (‘DM’) water was taken in a bucket. 300 ppm hardness water was prepared by adding calcium chloride and magnesium sulphate powder to the DM water in 2: 1 ratio. The hardness of water was measured using water hardness tester.

[0100] Washing procedure using Tergotometer: 5 gm / 1 solution of the detergent formulations was prepared using 300 ppm hardness water. The soiled cloth samples were introduced into steel containers and agitated for 10 minutes where the soiled cloth sample to water ratio was 1 : 100. The samples were washed for 10 minutes at 27 ± 2°C at 120 rpm speed. The samples were washed 3 times with 300 ppm hardness water for a duration of 10 minutes for each wash. The washed samples were dried in a dryer for 45-60 minutes in warm condition avoiding heat to reduce degradation of soil.

[0101] Calculation of soil removal: Hunterlab’s LabScan® XE spectrophotometer was used for measuring reflectance. A small aperture port plate was used, and the spectrophotometer was calibrated using black and white tiles as per the standard procedure provided with the machine. The measurement parameters were selected as - CIELAB system, 457 nm brightness, D 65 light source, 10° observer, L*, a*, b*. The reflectance of each of the washed sample is then taken at 5 different locations and finally average of 5 readings was taken as the reflectance of the washed sample (Rw). Table 9 shows result containing % soil removal calculated using the formula:

[0102] Percentage where where Rc, Rw, and Rs are reflectances of clean, washed and soiled cloth samples respectively.

[0103] Table 9: Stain Removal Data Example 15: Biodegradation test for the ECSA obtained in Example 9

[0104] Method: OECD 301B biodegradation test was used to test biodegradation of the ECSA obtained in Example 9. A measured volume of a mineral medium inoculated with an inoculum derived from sewage effluent source, with a known concentration of the test substance (10-20 mg DOC or TOC / 1) as the nominal sole source of organic carbon was aerated by the passage of carbon dioxide-free air at a controlled rate in the dark or in diffuse light. Degradation was followed over 28 days by determining the carbon dioxide produced. Carbon dioxide produced was trapped in barium or sodium hydroxide and was measured by titration of the residual hydroxide or as inorganic carbon. The amount of carbon dioxide produced from the test substance (corrected for that derived from the blank inoculum) was expressed as a percentage of theoretical CO2.

[0105] Result: FIG. 4 is a graphical representation of the results of biodegradability tests OECD 301B. It was concluded that more than 61% biodegradation happened in 14 days. Hence, the tested ECSA is readily biodegradable.

[0106] Example 16: Skin irritation test for the sodium salt of ECSA obtained in Example 9

[0107] Method: IS 13424 (2001) test was used to test skin irritation of sodium salt of the ECSA of Example 9. 8% w / w dilution of the ECSA of Example 9 was prepared in distilled water and used as a test product. Filter papers dipped in the test product (containing approximately 0.04 ml of the test product) were filled in wells of patch chambers and applied on back of participant and occluded. Patches were applied for a contact period of 24 hours and skin reaction was assessed under a constant artificial daylight source. The marked sites were scored post 24 hours after removal of the patches. Reactions such as erythema, dryness and wrinkling were scored on a 0-4 point scale and oedema on another 0-4 point scale (Draize test).

[0108] Results: The results of the test are presented in FIG. 5. The test products were dermatologically tested and found to be “Non-Irritant” based on IS 13424:2001 (Reaffirmed 2019) guidelines, Safety Evaluation of Bathing Bars and Toilet Soaps. INDUSTRIAL APPLICABILITY

[0109] The disclosed ECSA is an environment friendly surfactant. It can be incorporated in a wide range of compositions or formulations such as household and industrial liquid cleaning formulations. The surfactant can be used for cleaning textile and non-textile surfaces such as metal, stone, and plastic. The process for preparing the ECSA is economical and ecofriendly. The process avoids the use of hazardous solvents during sulfonation step. The process also does not generate harmful effluents.

Claims

We Claim:

1. An ethoxylated cardanol sulphonic acid represented by Formula I:Formula I wherein: n = 7-20R = H or SO3H2. The ethoxylated cardanol sulphonic acid as claimed in claim 1, wherein Ris H or SO3H.

3. The ethoxylated cardanol sulphonic acid as claimed in any of the preceding claims, wherein n is 9-15.

4. The ethoxylated cardanol sulphonic acid as claimed in any of the preceding claims, having a pH in the range of 1-4 in 1% aqueous solution.

5. The ethoxylated cardanol sulphonic acid as claimed in any of the preceding claims, having a surface tension in the range of 35-50 N / m in 1% aqueous solution.

6. The ethoxylated cardanol sulphonic acid as claimed in any of the preceding claims, having a viscosity in the range of 2500-15000 cps at room temperature.

7. The ethoxylated cardanol sulphonic acid as claimed in any of the preceding claims, having a Hydrophilic-Lipophilic Balance (‘HLB’) value in the range of 12-15, when calculated theoretically.

8. A formulation comprising the ethoxylated cardanol sulphonic acid as claimed in any of the preceding claims and a component selected from the group consisting of an anionic surfactant, a non-ionic surfactant, an secondary surfactant, a builder, an alkali agent, a salt, an anti-redeposition additive, a chelating agent, an optical brightener, an enzyme, a free flow agent, a buffering agent, a colour, a preservative, a fragrance, a filler, a dispersion agent, a stabilizer, water, and combinations thereof.

9. A process for preparing an ethoxylated cardanol sulphonic acid, represented by Formula IFormula I wherein: n = 7-20R = H or SO3H; the process comprising reacting 1 mol of an ethoxylated cardanol oil with about 0.8-2.0 mol of a sulfonating agent at a temperature in the range of 10- 130°C to obtain the ethoxylated cardanol sulphonic acid.

10. The process as claimed in claim 9, wherein 1 mol of the ethoxylated cardanol oil is reacted with 0.9-1.25 mol of the sulfonating agent.

11. The process as claimed in any of claim 9 or 10, wherein the ethoxylated cardanol oil is reacted with the sulfonating agent at a temperature in the range of 25-120°C.

12. The process as claimed in any of the preceding claims, wherein the sulfonating agent is selected from the group consisting of sulphuric acid, oleum, SO3 gas, chlorosulphonic acid, and combinations thereof.

13. The process as claimed in any of the preceding claims, wherein the sulfonating agent is sulphuric acid.

14. The process as claimed in any of the preceding claims, wherein the ethoxylated cardanol oil is obtained by reacting 1 mol of cardanol oil with 7-20 mol of ethylene oxide at a temperature in the range of 140-170°C.

15. The process as claimed in claim 14, wherein 1 mol of the cardanol oil is reacted with 9-15 mol of ethylene oxide.

16. The process as claimed in any of claim 14 or 15, wherein the cardanol oil is reacted with ethylene oxide at a temperature in the range of 150-160°C.

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