Description:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION

(See Section 10 and Rule 13)

1. TITLE OF INVENTION:
AN IMPROVED PROCESS FOR PURIFYING CRUDE WAX

2. APPLICANT:
PRAJ INDUSTRIES LIMITED,
Praj Tower" 274 & 275/2, Bhumkar Chowk,
Hinjewadi Road, Hinjewadi,
Pune 411057, India.

3. PREAMBLE TO THE DESCRIPTION

The following specification describes the invention and the manner in which it is to be performed

4. DESCRIPTION
CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
The present application does not claim priority from any other patent application.
TECHNICAL FIELD
The present subject matter, in general, relates to the field of process chemistry. More particularly, the present subject matter relates to an improved process for purifying crude wax.
BACKGROUND
Over the last decade, there has been a remarkable surge in innovations from natural, bio-based renewable chemicals and materials (RCM) stemming from an outlook of sustainable decarbonization through circular economy, a cyclic system focused on material efficiency by eliminating waste by turning goods that are at the end of their life cycle into resources for new ones, and by maximizing the utilization capacity of goods. RCM produced from bio-based feedstocks are sustainable alternatives to products made from fossil resources, especially in the cosmetic, personal care, and food industries. Moreover, bio-based ingredients and products also offer a far safer alternative to chemical-based products from a health standpoint. Many bio-active ingredients such as emollients, emulsifiers, waxes, surfactants, antimicrobial cosmetics are derived from natural sources and are being extensively studied for their applications in cosmetic, personal care, and food industries.
There are several FDA-approved plant-based waxes that have currently gained GRAS status, allowing for extensive food and cosmetic applications. Some examples of plant-based waxes are candelilla wax, carnauba wax, rice bran wax, sunflower wax, etc. Crude wax comprising about 30 % to 50 % of crude oils worldwide is generated as a byproduct during the oil refining/winterization process. While this byproduct has certain low value applications, purifying renders it into a commercial product with substantial applicability in various industries such as paper, food, cosmetics, personal care, and pharmaceuticals.
Sunflower wax finds applications in cosmetics, personal care, and pharmaceuticals, as a replacement to petroleum, and synthetic waxes, and thus largely contributes to the natural cosmetic industry. It is known to improve oil binding in sticks. It can also provide emollience, film formation and lubricity and is most commonly used in lipsticks and other anhydrous color cosmetics, foundations, mascaras, skin and hair care. Crude sunflower wax comprises of long chain, saturated C-42 to C-60 esters, that imparts hardness, crystalline structure, and a high melting point to the wax. In addition to this, it also comprises more than 40% oil, due to which, the saponification value, and the iodine value of the crude sunflower wax is about 150 mg KOH/g, and 65-70 mgI2/100g respectively. A high saponification value of 150 mg KOH/g is not suitable for cosmetic applications and is required to be lowered by removing impurities causing the high saponification value. Furthermore, a low iodine value is necessary for cosmetic-grade sunflower wax to demonstrate better stability, emulsion property, color, and hardness, which is achieved by separating unsaturated oil from the crude wax. Both the saponification value, as well as the iodine value play a crucial role in determining the applicability of wax in cosmetics, and pharmaceuticals. So, purifying the crude sunflower wax by removing oil to get more than 98% pure wax is extremely pivotal.
Conventionally, during wax purification, de-oiling is carried out by using known mechanical processes, such as, hydraulic pressure filtration, vacuum filtration, and centrifugal separation or by using solvents which demonstrate high oil solubility and exhibit poor or nil wax solubility. Moreover, only solvents that are safe for humans can be employed. Thus, cosmetic, personal care, and pharmaceutical applications of wax mandate solvents of high purity that are safe for consumption or topical applications. Further, solvents are required to be optimized basis properties such as dielectric constant, dipole moment, and polarity index that play a crucial role in determining their oil solubility. In addition to this, the solvents are also required to be characterized basis the solvent ratios and process parameters that aid in improving residual oil removal from crude wax.
It is conventionally known that crude wax, which is dark in color due to the presence of colored bodies, post the de-oiling process, lightens to grades of pale to light yellow. Thus, in most cases further refining of the de-oiled wax to remove undesirable colors is carried out to enhance its applicability.
Another variable that determines the applicability of the de-oiled wax is its peroxide value (PV). This value is a useful indicator of the extent of oxidation of lipids, fats, and oils. A lower number of peroxide value (PV) indicates a good quality of wax and a good preservation status.
In pursuance of this, the inventors of the present disclosure have arrived at a standardized process for purifying crude wax, and particularly purifying crude sunflower wax, for cosmetic applications. In addition to this, the inventors of the instant disclosure have also disclosed a process for purifying other natural waxes such as crude carnauba wax, crude rice bran wax, and crude bees’ wax.

SUMMARY
An embodiment of the present invention relates to a process for purifying crude wax; said process comprising, de-oiling the crude wax using a solvent to obtain wax cake; drying the wax cake to obtain refined wax; and treating the refined wax with an adsorbent to obtain purified wax; such that, said purified wax has reduced peroxide value (PV) and oil content.
An exemplary embodiment of the present invention relates to a process for purifying crude sunflower wax; said process comprising, de-oiling the crude sunflower wax using a solvent to obtain sunflower wax cake; drying the sunflower wax cake to obtain refined sunflower wax; and treating the refined sunflower wax with an adsorbent to obtain purified sunflower wax; such that, said purified sunflower wax has reduced peroxide value (PV) and oil content.
This summary is not intended to identify all the essential features of the claimed subject matter, nor is it intended to be used in determining or limiting the scope of the claimed subject matter.
BRIEF DESCRIPTION OF DRAWINGS
The detailed description of drawings is outlined with reference to the accompanying figures. In the figures, the left-most digit (s) of a reference number identifies the Figure in which the reference number first appears. The same numbers are used throughout the drawings to refer to features and components.
Fig. 1 demonstrates a process flow diagram (PFD) of the instant invention, wherein a stepwise purification of crude wax to obtain purified wax is presented.
Fig. 2 demonstrates the variation in oil content during stepwise extraction/de-oiling process (1st oil extraction, 2nd oil extraction, and 3rd oil extraction).
Fig. 3 demonstrates images of crude (A) and purified (B) samples of sunflower wax.
Fig. 4 demonstrates Gardner and APHA color measurement for ATSM D1544, and ATSM D1209 standards wherein the colors of crude (A) and purified (B) sunflower waxes (10% w/v in toluene) (Tubes 2 of 4(A) and4(B)) were compared/correlated with in-house samples of aqueous lactic acid (Tubes 1 of 4(A) and 4(B)).
DETAILED DESCRIPTION
Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” “alternate embodiment”, or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” or “in an embodiment”, “in an alternate embodiment”, or “in a related embodiment” in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.
Reference throughout the specification to “components”, “component”, “features”, or “feature” means a constituent or group of constituents embodying the process.
Before the present process is described, it is to be understood that this disclosure is not limited to the particular process as described, as there can be multiple possible embodiments which are not expressly illustrated in the present disclosure but may still be practicable within the scope of the present disclosure.
Also, the technical solutions offered by the present disclosure are clearly and completely described below. Examples in which specific conditions may not have been specified, have been conducted under conventional conditions or in a manner recommended by the manufacturer.
The present disclosure relates to a process for purifying crude wax.
An exemplary embodiment of the present disclosure relates to a process for purifying crude wax; said process comprising, de-oiling the crude wax using a solvent to obtain wax cake; drying the wax cake to obtain refined wax; and treating the refined wax with an adsorbent to obtain purified wax; such that, said purified wax has reduced peroxide value (PV) and oil content.
For the purpose of the instant disclosure and as is conventionally perceivable to a skilled person in the art, the terms “reduced”, “reduce”, “reduction”, or “reduces”, relate to a decrease in the value of a feature of wax cake, refined wax, or purified wax, as compared to the value of the said feature of at least one of crude wax, wax cake, or refined wax; wherein the said feature is at least one of peroxide value (PV), oil content, iodine value, and saponification value. Further, for the purpose of instant disclosure, purification is defined as the separation of a chemical substance of interest from foreign or contaminating substances.
In an embodiment of the instant disclosure, the crude wax is a natural crude wax; and preferably, at least one of crude sunflower wax, crude bees’ wax, crude carnauba wax, or crude rice bran wax.
In a related embodiment, the crude wax is a plant-based crude wax; and particularly, at least one of crude sunflower wax, crude carnauba wax, or crude rice bran wax.
It is known that due to the high percentage of oil in the wax, the saponification, and the iodine values of the crude wax are high - about 150 mg KOH/g, and 65-70 mgI2/100g, respectively in crude sunflower wax. These values are required to be lowered through purification to effectuate applicability of crude waxes in cosmetic, and pharmaceutical industries.
The present disclosure relates to a process for purifying crude wax; said process comprising de-oiling the crude wax.
For the purpose of this disclosure, de-oiling is defined as an extraction process in which oil is removed/separated from crude wax.
In an embodiment, de-oiling is carried out using at least one of hydraulic press, filter press, specifically designed filters, or reflux system; and preferably, reflux system.
The instant disclosure relates to de-oiling the crude wax using conventionally known organic solvents, and mixtures thereof; and preferably, using solvents which have highest solubility of oil and minimum or no solubility of wax.
In a related embodiment, the ratio of crude wax to solvent to be used for de-oiling is ranging from 1:1 to 1:10.
It is fundamentally known that cosmetic, personal care, and pharmaceutical applications of wax require solvents that are safe to be used in tropical applications. Thus, high purity solvents that are safe for consumption or contact with the human body, such as food grade solvents; and preferably, class 3 food grade solvents are recommended.
In a preferred embodiment, the solvent for de-oiling is at least one of acetone, hexane, ethyl acetate, ethanol, n-propanol, isopropanol or mixtures thereof; and particularly, acetone.
In a related embodiment, crude wax mixed with a solvent is refluxed at a temperature ranging from 20°C to 80°C, and preferably, from 40°C to 60°C.
In a further embodiment, crude wax mixed with a solvent is refluxed for about 3 hours; and preferably, for about 1 hour.
In the instant disclosure, de-oiling provides edible oil as a by-product; wherein, the edible oil is at least one of sunflower oil, or rice bran oil, that can be further processed for edible applications.
The instant disclosure relates to stepwise de-oiling process; and preferably a three-step de-oiling process to obtain de-oiled wax which is further cooled.
In one embodiment, the de-oiled wax is cooled to a temperature ranging from 10°C to 20°C; and preferably ranging from 12°C to 17°C to obtain cooled wax.
The cooled wax is separated from the solvent, preferably using filtration systems selected from pressure filtration, depth filtration, or others known to a skilled person; and particularly, closed vacuum filtration.
In an embodiment, the filtration system comprises filters having pore size ranging from 1 µm to 15µm; and particularly, 2-10µm.
Filtration of cooled wax provides wax cake; preferably having reduced oil content; and more preferably having reduced iodine value; and particularly having reduced saponification value.
In one embodiment, the reduced oil content of the wax cake is =1%.
In another embodiment, the reduced iodine value of the wax cake ranges from 5 to 17 mgI2/100g.
In a further embodiment, the reduced saponification value of the wax cake is 75-95 mg KOH/g. In yet another further embodiment, the reduced peroxide value (PV) of the wax cake is < 10 Meq/kg; and preferably, is < 5 Meq/kg.

In an embodiment, the wax cake is dried to obtain refined wax by applying at least one of un/solar drying, hot air, osmotic dehydration, oven, microwave assisted drying, infra-red, freeze, vacuum, or combinations thereof known to a skilled person; and preferably, by applying oven connected with condenser, agitated Nustch filter and drier.
In a related embodiment, wax cake is dried under vacuum; and preferably using a rotary vacuum drier.
In an embodiment, drying of the wax cake is carried out at a temperature ranging from 40°C to 70°C; and preferably, ranging from 45°C to 65°C.
In a related embodiment, drying of the wax cake is carried out for up to 6 to 15 hours; and preferably, for up to 6 to 10 hours.
The instant disclosure further relates to treating the refined wax with an adsorbent to obtain purified wax. It is known that an adsorbent is conventionally used for removing/separating undesirable components from a solution.
In one embodiment, the adsorbent for treating refined wax is selected from activated carbon, activated charcoal, aluminium silicate, silica gel, magnesium silicate or combinations thereof known to a skilled person; preferably, from aluminium silicate, silica gel, magnesium silicate or combinations thereof; and preferably, the adsorbent is magnesium silicate.
In a related embodiment, the refined wax is treated with the adsorbent at a temperature ranging from 80°C to 100°C; and preferably, at a temperature ranging from 85°C to 95°C.
In yet another related embodiment, the refined wax is treated with the adsorbent for up to 5 hours; and preferably, for up to 2 hours.
In a further embodiment, the refined wax is treated with the adsorbent at a ratio ranging from 1% to 10%; preferably, at a ratio ranging from 3% to 7%; and particularly, at 5%.
It is also known that an adsorbent helps in reducing peroxide value by absorbing polar compounds, hydroperoxides, and color bodies from the refined wax by physical adsorption. The color of the purified wax obtained as a result can be determined by applying known standardized color determining methods such as ASTM procedural standards.
In a preferred embodiment, the color of the purified wax is lightened to =1 according to ASTM D1544 standards.
In yet another preferred embodiment, the color of the purified wax is lightened to =15 Hazen according to ASTM D1209 standards.

The adsorbent further reduces the peroxide value (PV) of the refined wax.
In an embodiment, the reduced peroxide value (PV) is = 10 Meq/kg; and preferably is 0 to 5 Meq/kg.

In the instant disclosure, the wax obtained as a result of the adsorbent treatment is filtered by implementing at least one of the filtration systems described above to obtain molten purified wax, which is further dried to obtain purified wax.
In an embodiment, drying of the molten purified wax is carried out at a temperature ranging from 30°C to 80°C; and preferably, ranging from 45°C to 65°C.
In another embodiment, drying of the molten purified wax is carried out for up to 15 hours; preferably, for up to 6 to 10 hours.
The purified wax obtained as a result has reduced peroxide value (PV); preferably has reduced oil content; more preferably has reduced saponification value; and particularly has reduced iodine content.
In an embodiment, the reduced peroxide value (PV) of the purified wax is <5 Meq/kg.
In another embodiment, the reduced oil content of the purified wax is =1%.
In a further embodiment, the reduced saponification value of the purified wax is 75-95 mg KOH/g.
In yet another further embodiment, the reduced iodine value of the purified wax ranges from 5 to 17 mgI2/100g.
The purified wax finds application in cosmetics, personal care, and pharmaceuticals; and preferably, in cosmetic applications.

An exemplary embodiment of the instant disclosure further relates to a process, as described above, for purifying crude sunflower wax, said process comprising, de-oiling the crude sunflower wax using solvent to obtain sunflower wax cake; drying the sunflower wax cake to obtain refined sunflower wax; treating the refined sunflower wax with adsorbent to obtain purified sunflower wax; such that, said purified sunflower wax has reduced peroxide value (PV) and oil content.
In one embodiment, the reduced iodine value of the purified sunflower wax ranges from 5-15 mgI2/100g.
In another embodiment, treating the refined sunflower wax with adsorbent lightens the color of the purified sunflower wax. In a related embodiment, the color of the purified sunflower wax is lightened to =1 according to ASTM D1544 standards.
In yet another related embodiment, the color of the purified sunflower wax is lightened to =15 Hazen according to ASTM D1209 standards.
In a further embodiment, the saponification value of said purified sunflower wax ranges from 75-95 mg KOH/g.
Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated but is to be accorded the widest scope consistent with the principles and features described herein.
The foregoing description shall be interpreted as illustrative and not in any limiting sense. A person of ordinary skill in the art would understand that certain modifications could come within the scope of this disclosure. The features and properties of the present disclosure are described in further detail below with reference to examples.
Example 1
Comparative study of solvents as extraction/de-oiling agents
It is known that solvents with lower dipole moment, dielectric constant, and polarity can be applied for solubilizing non-polar compounds like oil. Thus, hexane, ethyl acetate, and acetone were screened for wax dissolvability / efficiency by performing de-oiling in a single step. For this, crude sunflower wax was independently mixed with each of the solvents. The mixture was refluxed at a temperature of about 45°C to 55°C for up to 2 hours to effect de-oiling in a single-step and obtain de-oiled sunflower wax. The de-oiled sunflower wax was cooled and then filtered by means of a solid-liquid separation unit comprising filters having pore size ranging from 2 to 10 µm. The process was carried out in a closed system to avoid solvent loss. The obtained sunflower wax cakes were analysed for acid value, saponification value, iodine value, oil content, and yield (see Table 1).

Table 1: Solvent analysis/screening by one-step de-oiling
Parameters/Solvent Crude sunflower wax Acetone Hexane Ethyl Acetate
Acid Value (mg KOH/g) 4.38 3.11 4.31 2.45
Saponification Value (mg KOH/g) 131.08 87.76 123.93 101.33
Iodine Value (mgI2/100g) 53.85 12.68 56.22 37.38
Oil Content (wt%) 42.08 7.62 33.72 23.48
As observed from Table 1, acetone showed the highest reduction of oil content in the first de-oiling step/single step de-oiling.
Example 2
Stepwise extraction of crude sunflower wax using various solvents
Sunflower wax cakes obtained as a result of one-step de-oiling process in Example 1 were analyzed for oil extraction efficiency. The de-oiling method described in Example 1 was repeated twice to constitute a three-step de-oiling process. The sunflower wax cakes obtained as a result of this three-step de-oiling was also analysed for oil extraction efficiency, the results of which are displayed in Table 2.

Table 2: Step wise extraction of crude sunflower wax using various solvents.
Stage 1 2 3 1 2 3 1 2 3
Solvent Crude sunflower wax Acetone Hexane Ethyl Acetate
Oil content (wt%) 42.08 7.62 1.8 0.8 15.77 2.14 2.53 26.75 13.84 7.09
Iodine Value (mgI2/100g)
53.85 12.68 3.56 2.37 15.61 5.23 6.75 28.25 17.7 16.11
Mass transfer % (oil)
80.95 60.57 33.12
As seen from Table 2, acetone showed highest % of mass transfer and gave the highest reduction of oil content in the three-step de-oiling.
The (one-step, two-step, and three-step de-oiled) sunflower wax cakes extracted using acetone were further analysed for studying other parameters such as, acid value, saponification value, peroxide value, and wax purity % (see Table 3).
Table 3: Stepwise extraction of crude sunflower wax using acetone
Parameters One-step de-oiling Two-step de-oiling Three-step de-oiling
Acid Value (mg KOH/g) 3.11 3.01 0.67
Saponification Value (mg KOH/g) 87.76 80.67 80.01
Iodine Value (mgI2/100g) 12.68 3.56 2.37
Oil Content (wt %) 7.62 1.8 0.8
Peroxide Value (PV) (Meq/kg) 93.62 42.20 4.84
Wax (Purity) wt% 92.38 98.2 99.2

As seen from Table 2 & 3, three-step de-oiling of crude sunflower wax using acetone provided lower acid value, iodine value, oil content, and peroxide value. Further, =99% wax purity was also achieved.
Example 3
Oil extraction using combination of solvent.
Solvent mixture was prepared by mixing acetone and hexane in 1:1 ratio. Then, another solvent mixture was prepared by mixing acetone and ethyl acetate in 1:1 ratio. One-step de-oiling of crude sunflower wax was carried out using the said solvent mixtures (acetone + hexane (1:1), and acetone + ethyl acetate (1:1)), acetone, hexane, and ethyl acetate, as described in Example 1. The sunflower wax cakes obtained were analyzed for oil extraction efficiency (see Table 4).
Table 4: Comparative study of oil extraction efficiencies of different solvent systems
Solvent System Oil content after first stage oil extraction Oil extraction efficiency (%)
Acetone 7% 85%
Hexane 33% 34%
Ethyl acetate 23% 54%
Acetone + Hexane (1:1) 27.32% 45%
Acetone + Ethyl acetate (1:1) 19.76% 60%

As seen from Table 4, maximum oil content reduction was achieved using acetone as an independent solvent. Further, it was observed that the above-described solvent mixtures achieved comparable oil content reduction, inferring that de-oiling/extraction can be carried out using solvent mixtures as well.
Example 4
Optimization of solvent ratio
Crude sunflower wax was mixed with acetone in varying ratios of about - 1:1, 1:2, 1:3, 1:4, and 1:5, one at a time, to form mixtures. Then, a one-step de-oiling process was carried out as described in Example 1. The sunflower wax cakes obtained were analysed for oil extraction efficiency (see Table 5).
Table 5: Screening solvent ratio for maximum oil extraction
Solvent ratio (w/v) Oil content (%) (approx.)
1:1 Slurry not filterable
1:2 28.23
1:3 26.41
1:4 13.89
1:5 7.62

As seen from Table 5, maximum oil reduction was achieved with acetone in a ratio of about 1:5 (w/v). Thus, for the purpose of the instant disclosure, the ratio of the solvent was optimized to a ratio above 1:5 (w/v).
Example 5
Purification of crude wax to obtain refined wax
The sunflower wax cake obtained as a result of three-step de-oiling, as described in Example 2 using acetone, was further dried in an oven at a temperature of about 55°C for up to 8 hours under vacuum to obtain refined sunflower wax. The refined sunflower wax was either stored or processed for further purification.

Example 6
Screening of adsorbents
About 100g of refined sunflower wax obtained in Example 5 was treated with up to 5% concentration (depending on the feed of refined sunflower wax) of the adsorbents - aluminium silicate, silicon dioxide (silica gel), and magnesium silicate, one at a time, at a temperature of about 90°C for about 2 hours. Then, the adsorbent treated sunflower wax were filtered using a hot filtration system to obtain molten purified sunflower waxes, that were dried to obtain purified sunflower waxes, which were analysed for final PV (Meq/kg).
The characteristics of the purified sunflower waxes with respect to their peroxide values (PV) are presented in Table 6.
Table 6: Comparison of adsorbents for reduction of peroxide value (PV)
Adsorbent Initial PV (Meq/kg) Final PV (Meq/kg) in purified sunflower wax
Aluminium Silicate 213.95 7.54
Silicon Dioxide 213.95 5.84
Magnesium Silicate 213.95 3.86

As seen from Table 6, the refined sunflower wax treated with magnesium silicate achieved better final peroxide values (PV) (Meq/kg).
Example 7
Optimization of the concentration of adsorbent
About 100g of refined sunflower wax obtained in Example 5 was treated with varying concentrations of magnesium silicate (based on the feed of refined sunflower wax) –1%, 2%, 3%, 4%, and 5%, one at a time, and processed as described in Example 6 to obtain purified sunflower waxes, which were analyzed for final PV (Meq/kg) (see Table 7).

Table 7: Study of Peroxide value (PV) with sequential dosage of magnesium silicate
Adsorbent Percentage (% w/w) Initial PV (Meq/kg) Final PV (Meq/kg) in the purified sunflower wax
1% 112.78 15.54
2% 112.78 12.70
3% 112.78 5.84
4% 112.78 2.1
5% 112.78 0

As depicted in Table 7, the final peroxide value (PV) (Meq/kg) of about 0 was achieved with the use of about 5% wt magnesium silicate.
Then, the difference in the color of the crude (A) and purified (B) samples of sunflower wax as seen in Fig. 3 (obtained using about 5% wt magnesium silicate) was analysed by applying known color determining methods, such as ASTM D1544 (Gardner color scale), and ASTM D1209 (APHA color measurement) standards. As seen in Fig. 4, the colors of crude (A) and purified (B) samples of sunflower wax (10% w/v in toluene) (Tubes 2A and 2B) were compared/correlated with in-house samples of aqueous lactic acid (Tubes 1A and 1B) and reported in Table 8.
Table 8: Decolorization of purified sunflower wax
Color measurement method Crude sunflower wax Purified sunflower wax
ASTM D1544 (Gardner method) =2 =1
ASTM D1209 (APHA color measurement) =250 Hazen =15 Hazen

As seen from Figs. 3, and 4, and Table 8, the adsorbent lightened the color of the purified sunflower to =1 according to ASTM D1544 standards, and to =15 Hazen according to ASTM D1209 standards.
Example 8
Process for purifying crude sunflower wax using acetone.
500g of crude sunflower wax as specified in Table 9, having an oil content of about 50.59%, and a peroxide value (PV) of about 300.43 Meq/kg, was extracted step-wise (three step de-oiling), as described in Example 2, using about 5 litres of acetone (ratio of about 1:5 wt/vol) in the first step (one-step de-oiling), and about 2.5 litres of acetone (ratio of about 1:5 wt/vol) in the subsequent steps (two, and three-step de-oiling).
Table 9: Crude sunflower wax specifications
Parameters Crude Sunflower wax
Appearance & Color Visually off-white soft wax
(= 2 according to ASTM D1544 standards, and =250 according to ASTM D1209 standards)
Acid Value (mg KOH/g oil) <10
Saponification Value
(mg KOH/g oil) 130-180
Iodine Value (mgI2/100 gm) 40-90
Oil Content % (w/w) 40-60
Peroxide Value (Meq/Kg) Up to100

The sunflower wax cake obtained in the one, two, and three steps were analyzed separately (see Table 10). As seen from Table 10, one-step de-oiling/extraction reduced 74% oil, and 2.26% peroxide value. Further, two-step de-oiling/extraction reduced 97.4% oil, and 85.95% peroxide value. In addition to this, the three-step de-oiling/extraction reduced 98.8% oil, and 98.38% peroxide value.
Table 10: Characteristics of the sunflower wax cake
One-step Weight of sunflower wax cake (grams) (approx.) Oil content (approx.) Peroxide value (PV) (Meq/kg) (approx.)
243.21 13.15% 293.62
Total Reduction after one-step de-oiling 74% 2.26%

Two-step Weight of sunflower wax cake (grams) (approx.) Oil content (approx.) Peroxide value (PV) (Meq/kg) (approx.)
214.38 1.32% 42.20
Total Reduction after two-step de-oiling 97.4% 85.95%

Three-step Weight of sunflower wax cake (grams) (approx.) Oil content (approx.) Peroxide value (PV) (Meq/kg) (approx.)
211.6 0.24% 4.84
Total Reduction after three-step de-oiling 98.8% 98.38%

The sunflower wax cake was then processed as described in Example 5 to obtain refined sunflower wax. For further lowering peroxide value (PV), and de-colorizing the refined sunflower wax to make it commercially applicable, adsorbent in the form of about 21.16 g of magnesium silicate or activated carbon (about 5% concentration) was added to about 423.2 g of the previously obtained refined sunflower wax, and the mixture was processed as described in Example 6 to obtain purified sunflower wax that was further analysed for peroxide value and de-colorization (see Figs. 3, and 4, and Tables 6, 7, and 9).
Additionally, crude sunflower oil was obtained as a by-product.
Due to the implementation of a food grade solvent in the present case, the sunflower oil may be further processed for edible applications.
As is known to a skilled person in the art, saponification value, as well as the iodine value play a crucial role in determining the applicability of wax in cosmetics, and pharmaceuticals. Crude sunflower wax comprises more than 40% oil, due to which its saponification value, and iodine value is about 150 mg KOH/g, and 65-70 mgI2/100g respectively. A high saponification value (such as 150 mg KOH/g) and iodine value is unsuitable for cosmetic applications and thus is required to be lowered. Furthermore, for cosmetic use, a lower iodine value is necessary use to demonstrate better stability, emulsion property, color, and hardness, which is attained by removing unsaturated oil from crude wax. So, the de-oiling/extraction step/process plays a pivotal role in its purification in determining cosmetic, and pharmaceutical applicability of waxes.
Comparison of purified sunflower wax obtained in the present case, with cosmetic grade sunflower wax for determining/analyzing its cosmetic applicability is shown in Table 11.
Table 11: Comparison of inhouse refined sunflower wax with commercial cosmetic grade sunflower wax
Parameters
Acetone/1:5 (Example 4) Cosmetic-grade Sunflower wax Unit
Melting Point 78 74-80 °C
Saponification value 87.18 75-95 mg KOH/g
Iodine Value 7.66 5-15 mgI2/100 g
Acid Value 1.42 8 mg KOH/g

As seen from Table 11, the purified sunflower wax obtained in the instant case falls within the purview of the requisite cosmetic grade specifications.
The purified sunflower wax in the instant disclosure may be used as a replacement to petroleum and synthetic waxes for numerous applications. Due to lower saponification and iodine values, the said product may display better stability, emulsion property, color, and hardness, making it accessible for cosmetic applications.
The process of the instant disclosure may be applied to a wide range of crude sunflower waxes having oil content ranging from about 35-55% and peroxide values (PV) of about 300 Meq/kg.
Purification of crude bees’ wax, crude carnauba wax, and crude rice bran wax were also carried out similarly, as described in any of the preceding Examples 1-8.
Table 12: Oil extraction of various crude waxes
Parameters Crude Bees’ wax Purification process Carnauba wax 1-step rice bran wax 1-step
1-step 2-step 3-step
Oil & Grease (wt%) 6.51 5.46 3.47 2.23 1.3 0.66 5.24 1.32
Melting Point (°C) 74.6 - - - 82.6 - 78.6 -
Acid Value (mg KOH/g) 17.27 - - - 13.91 - 9.23 -
Moisture Content (%) 0.14 - - - 0.21 - - -
Sap Value (mg KOH/g) 106.52 - - - 102.73 - - -
Iodine Value (mgI2/100g) 9.14 8.19 10.09 7.14 11.98 11.84 22.57 16.03
Peroxide Value (Meq/kg) 1.9 ND ND ND 7.62 3.92 9.42 12.78

As seen from Table 12, the oil content of the purified bees’ wax after three-step de-oiling/extraction is about 2.23%. Further, the oil content of the purified carnauba wax after one-step de-oiling/extraction is about 0.66 %. In addition to this, the oil content of the purified rice bran wax after one-step de-oiling/extraction is about 1.32 %.
For the purpose of the instant disclosure, the crude sunflower wax, the crude bees’ wax, crude carnauba wax, and crude rice bran wax were obtained/sourced as commercially available by-products from oil refineries.
The embodiments, examples and alternatives of the preceding paragraphs or the description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.
The preferred embodiments of the present invention are described in detail above. It should be understood that ordinary technologies in the field can make many modifications and changes according to the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by those skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should fall within the protection scope determined by the claims.
, Claims:5. CLAIMS:
We claim:
1. A process for purifying crude wax; said process comprising:
de-oiling the crude wax using solvent to obtain wax cake;
drying the wax cake to obtain refined wax; and
treating the refined wax with adsorbent to obtain purified wax;
such that, said purified wax has reduced peroxide value (PV) and oil content.

2. The process as claimed in claim 1, wherein the crude wax is plant-based crude wax including at least one of crude sunflower wax, crude bees’ wax, crude carnauba wax, or crude rice bran wax.

3. The process as claimed in claim 1, wherein the ratio of crude wax to solvent used for de-oiling is ranging from 1:1 to 1:10.

4. The process as claimed in claim 1, wherein the solvent for de-oiling is at least one of acetone, hexane, ethyl acetate, ethanol, n-propanol, isopropanol or mixtures thereof.

5. The process as claimed in claim 1, wherein drying of the wax cake is carried out at a temperature ranging from 45°C to 65°C for up to 6 to 10 hours.

6. The process as claimed in claim 1, wherein the refined wax is treated with the adsorbent at a temperature ranging from 80°C to 100°C.

7. The process as claimed in claim 1, wherein the refined wax is treated with the adsorbent at a ratio ranging from 1% to 10%.

8. The process as claimed in claim 1, wherein the adsorbent for treating refined wax is selected from activated carbon, activated charcoal, aluminium silicate, silicon dioxide (silica gel), or magnesium silicate, or combinations thereof.

9. The process as claimed in claim 1, wherein the reduced oil content of the purified wax is =1%.

10. The process as claimed in claim 1, wherein the reduced peroxide value (PV) of the purified wax is <5 Meq/kg.

11. The process as claimed in claim 1, wherein the reduced iodine value of the purified wax ranges from 5 to 17 mgI2/100g.

12. A process as claimed in claim 1 for purifying crude sunflower wax, said process comprising:
de-oiling the crude sunflower wax using solvent to obtain sunflower wax cake;
drying the sunflower wax cake to obtain refined sunflower wax;
treating the refined sunflower wax with adsorbent to obtain purified sunflower wax;
such that, said purified sunflower wax has reduced peroxide value (PV) and oil content.

13. The process as claimed in claim 12, wherein the reduced iodine value of the purified sunflower wax ranges from 5-15 mgI2/100g.

14. The process as claimed in claim 12, wherein treating the refined sunflower wax with adsorbent lightens the color of the purified sunflower wax.

15. The process as claimed in claim 14, wherein the color of the purified sunflower wax is lightened to =1 according to ASTM D1544 standards.

16. The process as claimed in claim 14, wherein the color of the purified sunflower wax is lightened to =15 Hazen according to ASTM D1209 standards.

17. The process as claimed in claim 12, wherein saponification value of said purified sunflower wax ranges from 75-95 mg KOH/g.

6. DATE AND SIGNATURE

VAISHALI SAJJAN (IN/PA-1980)
FOR PRAJ INDUSTRIES LIMITED