Description:FORM 2

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

COMPLETE SPECIFICATION

(See Section 10 and Rule 13)

Title of invention:
PROCESS FOR BLEACHING WAXES

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

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

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 a process for bleaching waxes.
BACKGROUND
Waxes are essentially esters made of long-chain alcohol and fatty acids, that find application in cosmetics, food, pharmaceutical, and coating industries. The composition of the waxes depends on the geographical origin and location of their source. Based on which, waxes are typically divided into natural waxes and synthetic waxes.
Plants secrete natural waxes into and on the surface of their cuticles to control evaporation, wettability, and hydration. Vegetable waxes such as jojoba oil, rice bran wax, candelilla wax and ouricury wax are types of specialized plant waxes. Rice bran wax, extracted from the bran oil of rice (Oryza sativa), is an edible wax that demonstrates relatively high melting point. Rice bran wax is the byproduct of edible oil refineries which contains nearly 35% oil, 10-15% resinous matter and 50% wax. While this byproduct has certain low value applications, bleaching and further refining renders it into a commercial product with substantial applicability in various industries.
Due to a current surge in innovations from natural, bio-based renewable chemicals and materials (RCM), stemming from an outlook of sustainable decarbonization, there are several FDA-approved plant-based waxes that have currently gained GRAS status, allowing for their extensive food and cosmetic applications. At present, bleached and further refined rice bran wax finds application in various industries such as coatings, food, paints, textiles, pharmaceuticals, and cosmetics.
Montan wax, also known as lignite wax or OP wax, is a naturally occurring mineral wax extracted from coal and lignite. This hard fossilized wax is conventionally obtained through solvent extraction. Its color ranges from dark brown to light brown when crude. Its composition is non-glyceride long-chain (C24–C30) carboxylic acid esters (62–68 weight %), free long-chain organic acids (22–26%), long-chain alcohols, ketones, and hydrocarbons (7–15%), and optionally resins; which is in effect fossilized plant wax. Although the crude Montan wax directly obtained through solvent extraction is dark brown and odorous, it can be bleached and further refined to synthesize commercially useful products that show applicability in industries such as paints, polishes, paper, and cosmetics.
Vegetable as well as fossilized waxes comprise extensive amounts of oil, due to which the saponification, and the iodine values are higher, subsequently affecting their stability, emulsion property, and hardness.
Waxes also comprise coloring bodies that are responsible for their dark coloration. Conventionally known adsorbents are regularly implemented for removing these components to obtain lightened waxes. However, some waxes, such as fossil extracted Montan wax additionally comprise around 1%-40% of resinous matter, which further discolors them, rendering them unsuitable, especially in pharmaceutical, and cosmetic industries. The concentration of these resinous matter is required to be lowered to reduce the color value of the waxes.
Bleaching agents are routinely applied for reducing the color value of these waxes, however, there is still inadequacy/room for improvement in achieving the same.
Traditionally known bleaching agents such as chromic acid and sulfuric acid are conventionally implemented to bleach vegetable and mineral waxes. However, these agents are hazardous and polluting. The effluents generated through these agents are difficult to treat, and/or recycle. In addition to this, the application of sodium borohydride as a reducing agent is also not feasible due to its unsafe nature. Therefore, there is desperate need in the market to develop environmentally friendly processes for bleaching naturally occurring vegetable and mineral waxes.
In pursuance of this, the inventors of the present disclosure have standardized an ecologically sustainable process for bleaching waxes; and particularly bleaching vegetable and mineral waxes, such that said bleached waxes show reduced color value, and oil content.

SUMMARY
An embodiment of the present disclosure relates to a process for bleaching wax; and particularly relates to a process for bleaching vegetable or mineral wax.
Another embodiment of the present disclosure relates to a process for bleaching wax, such as vegetable wax or mineral wax; comprising, mixing the wax with a solvent to form a mixture; treating the mixture using a bleaching composition to obtain treated wax; and washing and drying the treated wax to obtain bleached wax; such that, color value of said bleached wax is reduced by at least 80%.
Further embodiment of the present disclosure relates to a process for bleaching mineral wax; and particularly Montan wax; comprising, mixing the Montan wax with a solvent to form a mixture; treating the mixture using a bleaching composition to obtain treated Montan wax; and washing, and subjecting the treated Montan wax to an adsorbent treatment to obtain bleached Montan wax; such that, color value of said bleached Montan wax is reduced by at least 80 %.
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) for single step bleaching of mineral wax (Montan wax).
Fig. 2 demonstrates a process flow diagram (PFD) for two step bleaching of mineral wax (Montan wax).
Fig. 3 demonstrates a process flow diagram (PFD) for bleaching vegetable wax (Rice bran wax)
Figs. 4-11 demonstrate the effect of bleaching composition comprising a combination of hydrogen peroxide and sodium chlorite as bleaching agents on crude Montan wax through Exp. 1-10 in Example 4; wherein, color value is obtained using Lovibond daylight 2000 color lab instrument. The results are analysed by comparing the change in color from dark brown (4-11 B) to light yellow (4-11 A).
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.
Waxes directly obtained as a byproduct from oil refineries or extracted from conventionally known fossil fuels have certain low value applications. However, bleaching, and further refining renders them into a commercial product with substantial applicability.
The present disclosure essentially discloses a process for bleaching wax.
The present disclosure relates to a process for bleaching wax; comprising, mixing the wax with a solvent to form a mixture; treating the mixture using a bleaching composition to obtain treated wax; and washing and drying the treated wax to obtain bleached wax; such that, color value of said bleached wax is reduced by at least 80%.
For the purpose of the instant disclosure and as is conventionally perceivable to a person skilled in the art, the terms “reduced”, “reduce”, “reduction”, or “reduces”, relate to a decrease in the value of a feature of treated wax, or bleached wax, as compared to the value of the said feature of at least one of crude wax, or treated wax; wherein the said feature is at least one of oil content, iodine value, color value, acid value, and saponification value.
In an embodiment of the instant disclosure, the wax is at least one of vegetable wax or mineral wax; and preferably, is at least one of sunflower wax, rice bran wax, or Montan wax.
In a related embodiment, the wax is crude wax. Amongst the various steps involved in bleaching waxes, of utmost importance is to maximize removal of resinous colored impurities that affect their applicability and use.
For the purpose of this disclosure, crude wax is commercially sourced. The term “crude wax” pertains to an untreated wax, i. e., wax with resinous matter, oil, and coloring compounds. Further, the term “bleached wax” pertains to crude wax which is free of resinous matter, oil, and some color compounds, and which requires further refining for complete purification.

An embodiment of the instant disclosure relates to a process for bleaching wax comprising mixing the wax with a solvent.
It is known that solvents such as, ethyl acetate, chloroform, methyl isobutyl ketone, butyl acetate, iso butyl acetate, tetra hydro furan, and methyl ethyl ketone, with lower polarity index can be applied for solubilizing non-polar compounds like oil.
However, it is also 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 one embodiment, the solvent is at least one of ethyl acetate, or butyl acetate; and particularly, the solvent is ethyl acetate.
In a related embodiment, the ratio of the solvent to the wax ranges from 1:1 to 1:20; and preferably ranges from 1:5 to 1:15.
Yet another related embodiment relates to mixing the wax with a solvent to form a mixture at a temperature ranging from 55°C to 95°C and preferably, ranging from 65°C to 75°C.
A further embodiment relates to a process for bleaching wax comprising mixing the wax with a solvent to form a mixture.
Removal of resinous colored impurities is essential for commercially implementing wax.
An embodiment of instant disclosure relates to treating the mixture using a bleaching composition.
In one embodiment, the bleaching composition comprises a combination of sodium chlorite, and hydrogen peroxide.
For the present purpose, the bleaching agents are implemented to “bleach” the wax by reducing its color value.
It is known that hydrogen peroxide is a completely natural, green product that occurs naturally and is ecologically friendly. Further, sodium chlorite is approved by FDA approved chemical that is widely used in food, cosmetic, and pharmaceutical industries. Thus, the bleaching composition implemented in the instant case is environmentally friendly in nature.
A related embodiment relates to treating the mixture using a bleaching composition to obtain treated wax.
For the purpose of this disclosure, to obtain treated wax, reaction is allowed to reach a temperature ranging from 50°C to 100°C; and preferably, 80°C to 100°C.
Further, reaction pressure is allowed to reach a range of 4 bar to 10 bar; and preferably, around 5 bar to 8 bar.
In an embodiment, the treated wax is allowed to cool; preferably to a temperature ranging from 30°C to 70°C; and preferably, from 45°C to 65°C.

Another embodiment of the instant disclosure relates to washing the treated wax.
For the purpose of this disclosure, the treated wax is washed using water; preferably, twice; particularly, to remove chloride and unreacted hydrogen peroxide.
In an embodiment, the treated wax is allowed to cool; preferably to a temperature ranging from 5°C to 25°C; and preferably, from 10°C to 20°C.
In a related embodiment, the treated wax is allowed to cool for 2h to 15h; preferably for 6h to 10h.

In a further embodiment, after cooling, the treated wax is filtered; preferably, through a filtration (solid-liquid separation) unit or lab scale Buckner funnel with Whatman paper; and particularly, to separate wet cake and filtrate.
In a related embodiment, a solvent is added to the wet cake to form a mixture; and preferably, stirred.
In yet another related embodiment, the mixture is filtered; preferably, through a filtration (solid-liquid separation) unit or lab scale Buckner funnel with Whatman paper.

Further embodiment relates to drying the treated wax; preferably, in an oven; and particularly at a temperature ranging from 45°C to 65°C.
In yet another further embodiment, the drying is carried out for 5h to 12h; and preferably, for 6h to 10h to obtain bleached wax.

In an embodiment, color value of the bleached wax is reduced.
In another embodiment, color value of the bleached wax is reduced by at least 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99%.
In yet another embodiment, color value of the bleached wax is reduced by at least 80%.
In a further embodiment, the color value of the bleached wax is = 7 the color value of the bleached wax ranges from 1 to 7.
The color of the bleached wax obtained as a result can be determined by applying known standardized color determining methods such as ASTM procedural standards. For the purpose of this disclosure, color value is obtained using Lovibond daylight 2000 color lab instrument. The results are analysed by comparing the change in color from dark brown to light yellow.

In an embodiment of instant disclosure, the process for bleaching wax is either a one-step process or a two-step process.
An embodiment relates to washing and drying the treated wax and mixing the obtained bleached wax with a solvent to form a mixture and repeating the processes for bleaching wax, as is described above.
In a preferred embodiment, bleached wax is obtained as a result of one-step process or a two-step process.

In an embodiment, oil content of the bleached wax is reduced; preferably to = 2%.
In a related embodiment, the bleached wax has reduced acid value, preferably, reduced saponification value; and particularly, reduced iodine value.

The present disclosure further relates to a process for bleaching Montan wax; comprising, mixing the Montan wax with a solvent to form a mixture; treating the mixture using a bleaching composition to obtain treated Montan wax; and washing, and subjecting the treated Montan wax to an adsorbent treatment to obtain bleached Montan wax; such that, color value of said bleached Montan wax is reduced by at least 80 %.
In a related embodiment, the Montan wax is with resin or without resin.

One embodiment relates to a process for bleaching Montan wax comprising mixing the Montan wax with a solvent to form a mixture.
In a related embodiment, the solvent is ethyl acetate.
In yet another related embodiment, the mixture is heated to a temperature ranging from 60°C to 90°C; and preferably from 65°C to 85°C; and particularly, stirred.
In a further embodiment, the solvent is recovered for repeated use.

Another embodiment relates to treating the mixture using a bleaching composition to obtain treated Montan wax.
In a related embodiment, the bleaching composition comprises a combination of sodium chlorite, and hydrogen peroxide.
In yet another related embodiment, the bleaching composition is added to the mixture in a step wise manner; preferably, such that, the bleaching composition is added to the mixture again after an interval of 0.5h to 3h; and particularly, after an interval of 0.5h to 2h.

In an embodiment, the mixture is allowed to cool at a temperature ranging from 20°C to 50°C; and preferably from 10°C to 20°C.
In a related embodiment, the mixture is crystallized; and preferably filtered for removing the solvent using vacuum filtration; and particularly dried to obtain treated Montan wax.

Another embodiment relates to washing the treated Montan wax; preferably using hot process water in a reactor equipped with heating mixing arrangement.
In a related embodiment, the treated Montan wax is washed at 85°C to 100°C; and preferably, at 90°C to 95°C.
In yet another related embodiment, the water layer is separated; preferably, using drain valve.
Further related embodiment relates to drying the treated Montan wax using conventionally known drying methods.

It is also known that adsorbents absorb polar compounds, hydroperoxides, oxirane oxygen, color bodies, as well as traces of water from the crude wax by physical adsorption.
In an embodiment, the adsorbent 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 particularly, the adsorbent is magnesium silicate.
Another embodiment relates to subjecting the treated Montan wax to an adsorbent treatment; preferably, under complete reflux.
In a related embodiment, the ratio of adsorbent to treated Montan wax ranges from 1:1 to 1:10; and particularly, ranges from 1:3 to 1:7.
Another related embodiment relates to subjecting the treated Montan wax to an adsorbent treatment at a temperature ranging from 60°C to 90°C; and preferably ranging from 65°C to 85°C.

In yet another related embodiment, the reaction mixture is allowed to cool at a temperature ranging from 20°C to 50°C; and preferably ranging from 25°C to 45°C to obtain top wax layer.
In yet another further embodiment, the adsorbent is separated by conventionally known methods of separation; and preferably, by decantation.

In a related embodiment, the top wax layer is filtered for removing the solvent as described above; and preferably dried under vacuum to obtain bleached Montan wax.

Alternatively, for the two-step process, the bleaching composition is added again in a step wise manner, and the entire process is repeated as described above to obtain bleached Montan wax.

In a preferred embodiment, the color value of the bleached Montan wax is reduced by at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95% or 99%; and preferably, by at least 80%.
In yet another preferred embodiment, the resin value of said bleached Montan wax is reduced by at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95% or 99%; and preferably, by at least 60%.

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
Solvent Screening
Single step bleaching of Montan wax (with resin) was carried out under reflux as described below to compare the performance of hexane and ethyl acetate as a solvent (see Table 1 wherein, solvent ratio – about 1:10, temperature – about 75°C, initial color of crude Montan wax -10 (Gardner)).
About 100g of crude Montan wax (with resin) was taken in round bottom flasks (connected to a reflux condenser) and mixed with ethyl acetate and hexane, independently to form mixtures. The mixtures were heated at about 75°C. An overhead stirrer was applied to carry out uniform mixing at about 800 rpm. After about 1h. of heating, a bleaching composition was added to the mixtures in a step wise manner to obtain treated Montan wax, that were crystallized, and water washed. The treated waxes were then charged in the vacuum for drying at about 45°C, and treated with one or more adsorbents and filtered to obtain bleached Montan waxes, which were analysed for reduction in the Final Color value (see Table 1).

[Table 1]
Wax type Solvent used Bleaching Agent % Time (h.) Final Color value
(Gardner Color (ASTM 1544))
H2O2 NaClO2
With Resin Ethyl Acetate 15 15 4 5
With Resin Hexane 15 15 4 9
With Resin Ethyl Acetate 15 15 5 4
As per Table 1, ethyl acetate gave better Final Color value reduction compared to hexane. So, for the instant disclosure, ethyl acetate was preferably implemented as the solvent.

Example 2
Screening and optimization of bleaching agents and absorbent for bleaching waxes
It is known that for bleaching fatty matter, a variety of bleaching agents or processes, including hydrogen peroxide, activated carbon, and ozonation, are typically used in the industry.
About 100 g of crude rice bran wax was treated with different concentrations of sodium chlorite (NaClO2), hydrogen peroxide (H2O2), ozonation, and activated carbon, independently, at around 80°C using ethyl acetate as the solvent (about 1:10 ratio) and screened for the reduction in the Final color value (see Table 2).

[Table 2]
Parameter/ Feed (crude rice bran) 6% NaClO2 (1:5 Ethanol) 5% H2O2 (on 100%) 5% H2O2 + 5% NaClO2 Ozonation Activated carbon
Melting Point (°C) 79.9 79.9 79.2 78.5 79.2 79.7
Acid Value (mg KOH/g) 10.4 28.61 11.99 14.14 23.17 12.76
Iodine Value (mgI2/100g) 12 16.31 11.54 8.81 6.32 17.55
Saponification value (mg KOH/g) 80.6 80.45 61.61 71.62 91.99 76.83
Peroxide Value (PV) (Meq/kg) 17.82 8.61 25.55 21 69.29 4.53
Final color value (Gardner Color (ASTM 1544)) 6 6 5 2+ 4 6

As per Table 2, Gardner colour obtained by ASTM 1544 was 5 Gardner, 6 Gardner, and 4 Gardner when crude rice bran wax was treated with H2O2, NaClO2, and ozonation process, respectively. Further, Gardner colour obtained by ASTM 1544 was between 2 and 3 when crude rice bran wax was treated with a combination of NaClO2, and H2O2.
So, for the instant disclosure, a combination of NaClO2, and H2O2 was preferably implemented in the bleaching composition to obtain bleached wax.

Example 3
Optimisation of dosage of bleaching agents for bleaching of crude vegetable wax
About 100 g of crude rice bran wax was treated with different concentrations of NaClO2, and H2O2, independently and in combination at a temperature of around 80°C using ethyl acetate as the solvent and screened for the reduction in the Final color value/ analysed (see Table 3).

[Table 3]
Parameter/ Feed (crude rice bran) 6% NaClO2 5% H2O2 5% H2O2 (on 100%) with 150 ppm NaOH 5% H2O2 + 5% NaClO2 4% H2O2+ 4% NaClO2 6%H2O2+4%NaClO2 4%H2O2+6%NaClO2 8%H2O2+2%NaClO2 2%H2O2+8%NaClO2
Melting Point (°C) 79.9 79.9 79.2 79.6 78.5 78.7 79.8 79.6 77.6 79.7
Acid Value (mg KOH/g) 10.4 28.61 11.99 11.62 14.14 12.66 10.6 11.39 12.19 10.47
Iodine Value (mgI2/100g) 12 16.31 11.54 11.91 8.81 12.13 11.52 16.16 9.51 14.68
Saponification value (mg KOH/g) 80.6 40.45 61.61 234.41 71.62 100.36 84.02 80.86 86.36 89.34
Peroxide Value (PV) (Meq/kg) 17.82 8.61 25.55 19.36 21 18.79 11.52 17.11 40 14.68
Final color value (Gardner Color (ASTM 1544)) 6 6 5 4 2+ 3 5 5+ 6 6+

As per Table 3, Gardner colour obtained by ASTM 1544 was 2+, and 3 when crude rice bran wax was treated with a combination of about 5% of NaClO2, and about 5% of H2O2, and a combination of 4% of NaClO2, and about 4% of H2O2, respectively.
So, in the instant disclosure, a combination comprising about 5% dose of each NaClO2, and H2O2 was preferably implemented in the bleaching composition to obtain bleached vegetable wax.

Example 4
Optimisation of process parameters and bleaching agent(s) for bleaching crude mineral wax
Effect of solvent ratio, temperature and time on bleaching was systematically studied using design of experiments (DOE) approach.
DOE approach enables to study the relationship between multiple input variables and key output variables in structured way. Box-Behnken design was used to generate higher order response surfaces using fewer required runs than a normal factorial technique.
Experiments in Table 4, 5 and 6 were carried out as suggested by Box-Behnken Design.
For this, about 100 g of crude Montan wax (without resin) was treated with different concentrations of NaClO2, and H2O2, independently and in combination, at a temperature of around 75°C using ethyl acetate as a solvent and screened for reduction in final color value (see Tables 4-6).

Table 4: Solvent ratio optimization
Solvent Ratio Step I Solvent Ratio Step II Solvent Ratio for Magnesol PV Final Color Value (Gardner)
(ASTM 1544)
1: 04 1: 04 1: 07 85.29 4
1: 05 1: 05 1: 05 46 4
1: 05 1: 05 1: 05 71 4
1: 05 1: 05 1: 05 57.68 4
1:06 1:06 1: 05 57.88 4
1: 07 1: 07 1: 05 62.4 4
1: 10 1: 10 1: 05 52.6 3
1: 10 1: 10 1: 05 51.34 3

Table 5: Temperature optimization
Sr No Solvent (1:10) (w/v) Temp (°C) Time (h.) Bleaching Agent % Final Color Value (Gardner)
(ASTM 1544)
H2O2 NaClO2
Original Montan wax 10
1.1 Ethyl Acetate 65 4 11 11 6
1.2 Ethyl Acetate 65 6 11 11 4
1.3 Ethyl Acetate 75 5 11 11 4
1.4 Ethyl Acetate 85 4 11 11 5
1.5 Ethyl Acetate 85 6 11 11 5
2.1 Ethyl Acetate 65 5 15 15 4
2.2 Ethyl Acetate 75 4 15 15 4
2.3 Ethyl Acetate 75 6 15 15 4
2.4 Ethyl Acetate 85 5 15 15 3
3.1 Ethyl Acetate 75 4 7 7 7
3.2 Ethyl Acetate 65 5 7 7 5
3.3 Ethyl Acetate 85 5 7 7 6
3.4 Ethyl Acetate 75 6 7 7 7

Table 6: Reaction time optimization
Sr No Solvent (1:10) (w/v) Temp (°C) Time (h.) Bleaching Agent % Final Color Value (Gardner)
(ASTM 1544)
H2O2 NaClO2
Original Montan wax 10
1 Ethyl Acetate 75 4 7 7 7
2 Ethyl Acetate 75 4 15 15 4
3 Ethyl Acetate 75 6 7 7 7
4 Ethyl Acetate 75 6 15 15 4
5 Ethyl Acetate 75 5 11 11 4

As per Tables 4-6, ethyl acetate as a solvent and =10% each of NaClO2, and H2O2 and = 4h. of reaction time achieved better bleaching i. e., highest reduction in color value of crude Montan wax (without resin) - Gardner color of 4.

Example 5
Process for bleaching crude mineral wax
Single step bleaching of crude mineral wax without resin (see Fig. 1)
Set up: About 100g of crude Montan wax (see Table 7) was taken in a round bottom flask (connected to a reflux condenser) and mixed with ethyl acetate in about 1:10 w/w proportion to form a mixture. The mixture was heated at about 75°C. An overhead stirrer was applied to carry out uniform mixing at about 800 rpm.

Table 7: Characteristics of crude Montan wax
Characteristics Crude Wax - With Resin Crude Wax – Without
Resin
Drop melt point [°C] 85-95 -
Acid value [mg KOH/g] 22-36 15 - 30
Saponification value (mg KOH/g) 75-100 75-100
Resin content (AL) [%] 8 - 16 max 2.5
Final Color Value (Gardner (ASTM 1544)) dark brown dark brown

Bleaching 1: After about 1h. of heating, a bleaching composition comprising about 8% of NaClO2, and H2O2 each was added to the mixture in a step wise manner with an interval of 1h to obtain treated Montan wax; such that, about 16% of NaClO2, and H2O2 each was added to the mixture. The reaction was continued for the next 3h.
Solvent Removal: After about 5h., the mixture was allowed to cool to a temperature of about 15°C and then crystallized for about 1 h to carry out solvent removal. The treated Montan obtained as a result was then separated from mother liquor using vacuum filtration and dried.
Water wash: The treated Montan wax was then washed with hot process water in a reactor equipped with heating mixing arrangement. For this, the treated Montan wax was heated to a temperature of about 95°C. Hot water (around 90°C) was added in about 1:10 proportion and mixed for about 2 to 3 mins by carrying out slow rotation at about 120-140 rpm. The mixture was then held for about 30 mins.
Wax drying: The water layer obtained as a result was separated using drain valve, and dried using vacuum at about 45°C.
Adsorbent treatment: The treated Montan wax was further subjected to about 2 % adsorbent treatment, preferably, magnesium silicate in a solvent medium (such as, ethyl acetate) in about 1:5 w/w ratio (w.r.t wax weight). The reaction was carried out at about 75°C for about 1h under complete reflux.
Solvent removal: Reaction mixture was then allowed to cool to about 37°C and separated. The top wax layer was separated by filtration. The filtered Montan wax was then dried under vacuum to remove trace of ethyl acetate and obtain bleached Montan wax, which was further sealed in an air sealed bag to avoid moisture contact.
The ethyl acetate filtrate (mother liquor) obtained during solvent removal and adsorbent treatment as a by-product, was recovered using distillation.

Two step bleaching of crude mineral wax (with resin (see Fig. 2)
Set up: About 100g of crude Montan wax was taken in a round bottom flask (connected to a reflux condenser) and mixed with ethyl acetate in about 1:10 w/w proportion to form a mixture. The further set up was carried out as described above.
Bleaching 1, and solvent removal: After about 1h. of heating, a bleaching composition comprising about 8% of NaClO2, and 8% of H2O2 was added to the mixture in a step wise manner to obtain treated Montan wax; such that, about 16% of NaClO2, and H2O2 each was added to the mixture again after an interval of 1h. The reaction was continued for the next 3h following which, the solvent removal step was carried out as described above.
Bleaching 2 and Solvent removal: For second bleaching, about 1:10 w/w proportion of ethyl acetate was mixed with the treated Montan wax to form a mixture again. The further processes of set up, bleaching 1, solvent removal, water wash, wax drying, adsorbent treatment, and solvent removal were carried out as described above. The ethyl acetate filtrate (mother liquor) obtained during solvent removal and adsorbent treatment as a by-product, was recovered using distillation.
Optimization of process parameters
Single as well as two-step bleaching of crude Montan wax (with/without resin) was carried out under different conditions as per procedure described above, at around 75°C for parameter optimization, wherein it was inferred that when crude Montan wax (with/without resin) is mixed with ethyl acetate (used as a solvent in about 1:10 ratio), and reacted with a bleaching composition comprising about 8% each of hydrogen peroxide, and sodium chlorite, and about 2% of adsorbent, the color value of said bleached Montan wax is reduced by at least 80%.
Table 8 shows the effect of the bleaching composition comprising a combination of hydrogen peroxide and sodium chlorite as bleaching agents on crude Montan wax (with/without resin).
[Table 8]
Exp Ethyl acetate solvent ratio Step 1 Bleaching Agents Ethyl acetate solvent ratio Step 2 Bleaching Agents Final Color value (Gardner (ASTM 1544)) Reference Fig.
H2O2 NaClO2 H2O2 NaClO2
Exp 1 01:10 8 8 01:10 8 8 4 G 4
Exp 2 01:07 8 8 01:07 8 8 5 G 5
Exp 3 01:07 8 0 01:07 8 0 = 9 G 6
Exp 4 01:07 0 8 01:07 0 8 5 G 7
Exp 5 01:07 8 0 01:07 0 8 7 G 8
Exp 6 01:07 0 8 01:07 8 0 7G 9
Exp 7 01:07 16 0 01:07 16 0 7 G 10
Exp 8 01:07 0 16 01:07 0 16 5 G 11

Color: The color of the crude Montan wax and the Bleached Montan wax was obtained using Lovibond daylight 2000 color lab instrument. The results were analysed by comparing the change in color from dark brown to light yellow. The procedure included measuring the color of crude Montan wax by taking about 0.1g of sample in about 10 ml of toluene and measuring the color in Lovibond daylight 2000 Color lab instrument, by considering 10ml of toluene as a reference.
Melting point: In this study the melting point of Montan wax was found by using capillary tube method (Veego melting point apparatus) (ASC.QC293).
Acid value: Acid value was analyzed by titrating the samples against 0.1N KOH with phenolphthalein as an indicator (ASC.QC128).
Iodine value: Iodine value was analyzed by referring to (ASC.QC129) norms.
Saponification value: Saponification value was analyzed using (ASC.QC130) method.

Batch analysis of Montan wax bleaching
For process optimization of two step crude Montan wax bleaching, four (4) batches of crude Montan wax (with/without resin) (see Table 9) were analysed.
[Table 9]
Solvent Ratio of solvent (w/w basis) Concentration of First Step Bleaching agent Concentration of Second Step Bleaching agent Acid Value (mg KOH/g) Iodine Value (g of I2/100g) Peroxide Value (PV) (meq/Kg) Final colour Value (Gardner

Batch 1 Ethyl acetate 1:7 H2O2 (50% solution) (8 % of feed w/w) NaClO2 (80% Extra Pure) (8 % of feed w/w) 22.97 3.07 14.85 7
Batch 2 Ethyl acetate 1:7 H2O2 (50% solution) (8 % of feed w/w) and NaClO2 80% Extra Pure (8 % of feed w/w) H2O2 50% solution (8 % of feed w/w) and NaClO2 80% Extra Pure (8 % of feed w/w) 30.25 4.5 38.92 5
Batch 3 Recovered Ethyl acetate 1:7 H2O2 (50% solution) (8 % of feed w/w) and NaClO2 80% Extra Pure (8 % of feed w/w) H2O2 (50% solution) (8 % of feed w/w) and NaClO2 80% Extra Pure (8 % of feed w/w) 26.62 3.59 6
Batch 4 Recovered Ethyl acetate 1:7 H2O2 (50% solution) (16 % of feed w/w) H2O2(50% solution) (16 % of feed w/w) 28.46 2.56 4.74 7

Ethyl acetate obtained as a by-product during solvent recovery and adsorbent treatment was recovered using distillation.
Acid value: Acid value was analyzed by titrating the samples against 0.1N KOH with phenolphthalein as an indicator (ASC.QC128).
Iodine value: Iodine value was analyzed by referring to (ASC.QC129) norms.
Peroxide value: Peroxide value was analysed by referring to (DFT.QC051) norms.
Colour: The colour of the crude Montan wax and the Bleached Montan wax was obtained using Lovibond daylight 2000 colour lab instrument. The results were analysed by comparing the change in colour from dark brown to light yellow.
As per Table 9, Batch 2 demonstrated better reduction in color value.

Example 6
Process for bleaching crude vegetable wax using single step bleaching of crude vegetable wax (see Fig. 3)
About 1 kg of crude rice bran wax as per Table 10 specifications was mixed with about 5 L. of ethyl acetate (w/v) to form a mixture. Then a bleaching composition comprising about 5% feed each of (about 0.05 kg of) NaClO2, and (about 0.05 kg of) H2O2 was added to the mixture to obtain treated rice bran wax. Reaction was allowed to reach a temperature of about 90°C under about 5 bar pressure for about 1h. Internal pressure increase observed was around 1.5 bar; whereby total reaction pressure reached was around 6.5 bar.
Table 10: Crude rice bran wax specifications
Parameters Crude rice bran wax
Acid value 10.81 mg KOH/g
Saponification value 122.65 mg KOH/g
Iodine value 23.59 g I2/100g
Peroxide value 57.57 mg KOH/g
Oil Content 6.12% (wt)
Melting Point 79.8°C
Gardner color (ASTM 1544) 6

The treated rice bran wax was cooled to a temperature of about 55°C. Then around 1 kg water (1% solution of sodium chlorite) was added to remove chloride and unreacted hydrogen peroxide. Two successive water washes were reported to be required to remove maximum chloride.
After washing, the treated rice bran wax was cooled to a temperature of about 15°C for about 8 h and then filtered through about 10µ filtration unit to separate the wet cake and filtrate which contained dissolved oil. About 2 L of ethyl acetate was added to the wet cake to form a mixture and stirred for about 30 mins at about 40°C. The mixture was then filtered through the filtration unit again. The filtered rice bran wax obtained as a result was allowed to dry in the oven at temperature of about 55°C for about 8h. under vacuum to obtain bleached rice bran wax that was further analysed.
The bleached rice bran wax showed about 0.78% oil content and Gardner Color – 1.

Example 7
Process for bleaching crude sunflower wax
About 1 kg of crude sunflower wax was mixed with about 5 L. of ethyl acetate (w/v) to form a mixture and the process was repeated as described in Example 6 to obtain bleached sunflower wax, that was further analysed.
The bleached wax had melting point of about 78°C, Acid value of about 1.37 mg KOH/g, Iodine value of about 7.05 g I2/100g, Saponification value of about 91.3 mg KOH/g, Peroxide value of about 4.03 meq/Kg, and Gardner color of about = 1.

Results and interpretation
- Colour value of rice bran wax is reduced to about 2-3 Gardner from about 8 Gardner using hydrogen peroxide and sodium chlorite as bleaching agents in the bleaching composition.
- Color value of crude Montan wax is reduced to about 5 Gardner from about 9 Gardner using hydrogen peroxide and sodium chlorite as bleaching agents in the bleaching composition.
- Ethyl acetate demonstrates better solvent properties to bleach wax in the present case.
- Present bleaching process is suitable for all type of vegetable and mineral waxes.
For the purpose of the instant disclosure, the natural vegetable waxes (crude, and bleached rice bran and sunflower wax), and fossil mineral waxes (crude and bleached Montan wax) were sourced as commercially available products.
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:We Claim:
1. A process for bleaching wax; comprising:
mixing the wax with a solvent to form a mixture;
treating the mixture using a bleaching composition to obtain treated wax; and
washing and drying the treated wax to obtain bleached wax;
such that, color value of said bleached wax is reduced by at least 80%.

2. The process as claimed in claim 1, wherein the wax is at least one of vegetable wax or mineral wax.

3. The process as claimed in claim 1, wherein the solvent is at least one of ethyl acetate, or butyl acetate.

4. The process as claimed in claim 1, wherein the ratio of the solvent to the wax ranges from 1:1 to 1:20.

5. The process as claimed in claim 1, wherein the bleaching composition comprises a combination of sodium chlorite, and hydrogen peroxide.

6. The process as claimed in claim 1, wherein the color value of the bleached wax is = 7.

7. The process as claimed in claim 1, wherein oil content of the bleached wax is reduced to = 2%.

8. The process as claimed in claim 1, wherein the process for bleaching wax is either a one-step process or a two-step process.

9. A process for bleaching Montan wax; comprising:
mixing the Montan wax with a solvent to form a mixture;
treating the mixture using a bleaching composition to obtain treated Montan wax; and
washing, and subjecting the treated Montan wax to an adsorbent treatment to obtain bleached Montan wax;
such that, color value of said bleached Montan wax is reduced by at least 80 %.

10. The process as claimed in claim 9, wherein resin value of the bleached Montan wax is reduced by at least 60%.

11. The process as claimed in claim 9, wherein the solvent is recovered for repeated use.

12. The process as claimed in claim 9, wherein the solvent is ethyl acetate.

13. The process as claimed in claim 9, wherein the bleaching composition comprises a combination of sodium chlorite, and hydrogen peroxide.

Dated this 20th Day of July 2023

Vaishali Sajjan [IN/PA-1980]
FOR PRAJ INDUSTRIES LIMITED