Corn wax oxides and esterification products

Abstract

The present invention relates to light-colored corn wax oxides, to a process for their preparation, and to their use for agricultural or forestry purposes, as additives in plastic processing, in care products, in printing inks and / or in paints, and to saponified or esterified corn wax oxides prepared by saponification or esterification of the said corn wax oxides.

Description

Technical Field

[0001] This invention relates to light-colored corn wax oxides, methods for preparing such corn wax oxide products, and their use for agricultural or forestry purposes as additives in plastics processing, in care products, in printing inks, and / or in paints. Saponified and esterified corn wax oxides, respectively prepared by saponification or esterification of the corn wax oxides of this invention, are also provided. Background Technology

[0002] The oxidation of fossil and non-fossil natural waxes with chromic acid has been known since the early 20th century and has been carried out industrially since 1927 using fossil lignite wax in the "Gersthofen process," which is still in operation today. These chromic acid-based processes can be used not only to oxidize fossil lignite wax but also to oxidize renewable natural waxes such as carnauba wax and candelilla wax. The chromic acid oxidation method for carnauba wax is described in DE-A 10231886. In their natural state, carnauba wax (fatty gray, type 4; medium yellow, primagelb, and "flor," types 3 to 1) and coarse lignite wax (black) are distinctly dark. Oxidation with chromic acid results in a lighter-colored wax product.

[0003] However, chromic acid oxidation of natural waxes leads to the cracking of wax esters and the in-situ oxidation of the resulting wax alcohols into wax acids. The acid value is a measure of the free wax acid content. Based on the ester group, the typical conversion rate of this oxidation is in the range of 50-90%.

[0004] DE-A1 10 2013 007638 discloses a method for preparing acid waxes with a defined acid value, in which a mixture formed from a natural wax ester and an α-olefin is oxidized with chromium sulfuric acid. The natural wax ester is selected from rice husk wax, carnauba wax, sunflower wax, and sugarcane wax.

[0005] DE-A1 10 2018 116113 discloses a method for preparing natural wax oxides using rice bran wax or sunflower wax as starting materials through a two-stage oxidation process.

[0006] EP-A1 3 102 292 discloses a process for preparing oxides from rice bran wax and lignite wax by treating them with chromium sulfuric acid.

[0007] US-A 4 083 731 discloses the preparation of lignite wax oxide and bark wax oxide, wherein lignite wax and bark wax are oxidized at 110°C using a mixture of chromium trioxide and concentrated sulfuric acid.

[0008] Natural waxes bleached in this way, in addition to the desired lightening of color, also have a higher saponification value and a higher acid value than unbleached waxes.

[0009] High acid values ​​often have the following advantages: after oxidation, natural wax oxides can be more easily separated from byproducts because the separation of the organic phase containing the wax oxides from the aqueous phase containing chromium salts and other water-soluble reaction products is favorable. However, at low acid values, phase separation has been observed to occur very slowly or sometimes not at all. If phase separation does not occur or occurs very slowly, it is often impossible to reliably separate and purify the natural wax oxides without considerable effort.

[0010] To achieve a high acid value that allows for effective phase separation, a much larger amount of chromium sulfate is required than is necessary to achieve a low acid value, thus generating a much larger amount of chromium salt waste. From both an economic and environmental perspective, avoiding this large amount of waste is desirable.

[0011] Typically, if the natural wax used has a high oil content, phase separation at low acid values ​​becomes more difficult, often necessitating pretreatment such as deoiling before oxidation. This can sometimes require large amounts of solvent, which is both economically and ecologically unfavorable.

[0012] To obtain a product with a low acid value from a natural wax oxide with a high acid value, the acid value of the wax oxide can be reduced after the separation and removal of byproducts, for example by esterification with an alcohol. This results in an additional synthetic step after the oxidation to obtain the natural wax oxide with a low acid value, which also presents economic and environmental disadvantages. In particular, if a specific application requires a natural wax oxide with a low acid value, it is advantageous to forgo the use of large amounts of chromium sulfide and subsequent acid value reduction via esterification, as well as the use of large amounts of solvent prior to the oxidation. Summary of the Invention

[0013] One object of the present invention is to provide a method for preparing natural wax oxides by chromium sulfide oxidation of natural waxes, wherein, after the oxidation, the natural wax oxides can be separated over a wide acid value range.

[0014] It has been surprisingly discovered that when corn wax is used as a natural wax, even when the corn wax has a relatively high oil content, the natural wax oxide can still be separated and purified after oxidation with chromium sulfuric acid, despite the low acid value.

[0015] This invention provides a method for preparing corn wax oxide (O), the method comprising the following steps:

[0016] i) Provide corn wax (MW);

[0017] ii) Provide a mixture (M) formed from chromium trioxide and sulfuric acid;

[0018] iii) Oxidation of corn wax (MW) by reacting it with the mixture (M) to obtain corn wax oxide (O);

[0019] iv) Terminate the reaction and allow the reaction mixture obtained in step iii) to stand until the organic phase separates from the aqueous phase;

[0020] v) Separate the organic phase;

[0021] vi) Optionally, remove the residue containing chromium compounds from the organic phase to obtain a purified form of corn wax oxide (O);

[0022] vii) Optionally, repeat the sequence of steps ii) to vi) using corn wax oxide (O) in the optional purified form instead of corn wax (MW).

[0023] This method allows for the direct acquisition of light-colored natural wax oxides based on corn wax—corn wax oxide (O)—with an acid value in the range of about 10 to about 170 mg KOH / g, without the need for additional steps after separation to adjust the acid value.

[0024] It has been found that when corn wax (MW) is used as a starting material, even at an acid value of about 10 mg KOH / g, a clear phase boundary can be regularly observed in step iv) of the method of the present invention to form between the organic phase and the aqueous phase. At acid values ​​ranging from 20 to 50 mg KOH / g, a clear phase boundary is typically identifiable in less than 1 minute in step iv) of the method of the present invention. At acid values ​​above 50 mg KOH / g, a clear phase boundary is often identifiable in less than 10 seconds in step iv) of the method of the present invention. The times given here were observed under the conditions given in the examples. These times may vary with significantly larger reaction batches, but even so, they are significantly shorter than those for oxides of other natural waxes (which are prepared under otherwise identical conditions).

[0025] At low to medium acid values, phase boundaries are clearly identifiable even when the oil content in the corn wax used is relatively high. Conversely, in the case of rice bran wax oxides, under otherwise identical conditions, phase separation often occurs only at acid values ​​above approximately 20 mg KOH / g, and only at low oil contents of <5% by weight, typically only at <2% by weight. In the case of lignite wax, phase separation often occurs even at acid values ​​of approximately 50 mg KOH / g.

[0026] The present invention further provides a corn wax oxide (O), which can be prepared by reacting corn wax (MW) with a mixture formed of chromium trioxide and sulfuric acid.

[0027] The corn wax oxides (O) of the present invention can be further modified, for example by esterification or saponification, so as to further adjust their acid value and / or change other properties, for example after the preparation of the corn wax oxides (O).

[0028] Esterification processes are typically carried out with alcohols, often polyols such as ethylene glycol, butanediol, glycerol, diglycerol, trimethylolpropane, ethylene glycol, pentaerythritol, or sorbitol.

[0029] The present invention further provides an esterified corn wax oxide (E), which can be prepared by reacting the corn wax oxide (O) of the present invention with an alcohol, preferably a polyol, more preferably ethylene glycol, butanediol, glycerol or pentaerythritol.

[0030] Saponification is typically carried out with basic metal salts, often alkali metal hydroxides and / or alkaline earth metal hydroxides. The present invention therefore further provides a saponified corn wax oxide (V), which can be prepared by reacting the corn wax oxide (O) of the present invention or the esterified corn wax oxide (E) of the present invention with a basic metal salt, preferably an alkali metal hydroxide and / or an alkaline earth metal hydroxide, more preferably with Ca(OH)₂.

[0031] The present invention further provides the use of the corn wax oxide (O), the esterified corn wax oxide (E), or the saponified corn wax oxide (V) of the present invention for agricultural or forestry purposes, as an additive in plastics processing, in care products, in printing inks, and / or in paints.

[0032] The present invention also relates to the use of corn wax (MW) in preparing natural wax oxides by oxidation with a mixture of chromium trioxide and sulfuric acid.

[0033] Corn wax is typically obtained from crude corn oil through multiple processing steps, which in particular include the basic decomposition of corn oil and various purification steps by chemical, thermal and / or mechanical separation processes. US 4272447 discloses a method in which wax is separated and removed from crude vegetable oil (e.g., corn oil) as an unwanted byproduct (about 60-90% by weight).

[0034] According to information from the Food and Agriculture Organization of the United Nations (FAO), maize is one of the most widely produced cereals. In 2018, the global maize harvest was approximately 1.147 billion tons.

[0035] During the processing of raw corn, and especially in the processing of corn oil obtained from it, corn wax is produced in large quantities as a byproduct. Its high yield and wide geographical distribution make corn wax an economically attractive natural wax.

[0036] Despite numerous analytical studies (with inconsistent findings), the chemical composition of corn wax remains unclear. However, it is certain that the waxy substance consists of wax esters. In "The Composition of Cornwax," R.L. Hinner (Journal of the American Chemical Society, 1927, 49, 1290-1294) claims that corn wax is at least partially composed of C 22 and C 24 The composition of fatty acids in beeswax alcohol esters. In "Wax Analysis of Vegetable Oils Using Liquid Chromatography on a Double-Adsorbent Layer of Silica Gel and Silver Nitrate-Impregnated Silica Gel" (Journal of the American Oil Chemists' Society 2001, 78, 401-410), G. Hénon described that the corn wax of autogenous corn oil can have a carbon chain length of 44 to 58 carbon atoms.

[0037] Corn wax esters are primarily composed of monoesters (hereinafter also referred to as "genuine esters") formed from long-chain, saturated, unbranched monocarboxylic acids and long-chain, unbranched, aliphatic monools. The acid components of the corn wax esters are mainly arachidic acid, betaine acid, and creosotenic acid with chain lengths of C20, C22, and C24, while the alcohol components mainly have chain lengths of C24, C26, C28, C30, and C32. In addition, the waxes may also contain free fatty acids and other components, such as squalene, phospholipids, and sterol esters.

[0038] The wax ester content in refined and deoiled corn wax is typically greater than 97% by weight. In undeoiled corn wax, the wax ester content, depending on the corn oil content, can be as low as 50% by weight. Other variable components in corn wax that can be considered "trace components" include undefined "dark matter," squalene, and substances referred to as "colloidal fractions." These components often result in product quality that is inconsistent in color and usability and is not easily reproducible.

[0039] The conventional technique for lightening the color of brown corn wax is considered to be classic bleaching using hydrogen peroxide. Hydrogen-bleached corn waxes are pale yellow, and their ester content and acid value largely correspond to the starting wax. These types are mainly supplied in the market as deoiled and refined corn waxes, but they also exhibit fluctuating product quality due to the presence of trace amounts of the aforementioned components.

[0040] Corn wax oxides with reduced acid values ​​compared to the starting wax can be prepared by means of the oxidation method described in DE 25 46 791B, which involves passing air through them at elevated temperatures. They therefore have acid values ​​below 10 mg KOH / g, since the acid value of crude corn wax is already below that level.

[0041] The method of the present invention can prepare light-colored corn wax oxide (O) with consistent product quality compared to bleaching with hydrogen peroxide.

[0042] The corn wax oxide (O) prepared by the method of the present invention typically has an iodine color value of less than 8 as measured according to DIN 6162 (2014) and a yellowness index of less than 50 as measured according to ASTM E 313-20. However, it has been found that by appropriately selecting the method parameters for oxidizing corn wax, an iodine color value of less than 6, typically less than 5, e.g., less than 2 as measured according to DIN 6162 (2014), and a yellowness index of less than 40, typically less than 30, e.g., less than 15 as measured according to ASTM E 313-20 can be selectively achieved.

[0043] At the same time, it also achieved a measurement of less than 10mm according to DIN 51579 (2010). -1 Typically less than 6mm -1 For example, less than 4mm -1 The penetration index is particularly advantageous for applications requiring hard wax.

[0044] The method of the present invention and the corn wax-based products of the present invention are described in more detail below.

[0045] The method of the present invention for preparing corn wax oxide (O) comprises the following steps (or consists of the following steps):

[0046] i) Provide corn wax (MW);

[0047] ii) Provide a mixture (M) formed from chromium trioxide and sulfuric acid;

[0048] iii) Oxidation of corn wax (MW) by reacting it with the mixture (M) to obtain corn wax oxide (O);

[0049] iv) Terminate the reaction and allow the reaction mixture obtained in step iii) to stand until the organic phase separates from the aqueous phase;

[0050] v) Separate the organic phase;

[0051] vi) Optionally, remove the residue containing chromium compounds from the organic phase to obtain a purified form of corn wax oxide (O);

[0052] vii) Optionally, repeat the sequence of steps ii) to vi) once or more using the corn wax oxide (O) in its optional purified form instead of the corn wax (MW).

[0053] The corn wax (MW) provided in step i) can be any corn wax.

[0054] If it is desired that the corn wax oxide (O) has a low to moderate acid value, such as 50 mg KOH / g or lower, the corn wax (MW) may contain up to 25% by weight, preferably up to 15% by weight, more preferably up to 10% by weight, and particularly preferably up to 5% by weight, based on the total weight of the corn wax (MW), of a polyester formed from a polyol and an aliphatic carboxylic acid having 8 to 20 carbon atoms. Typically, the corn wax (MW) contains more than 0.1% by weight of a polyester formed from a polyol and an aliphatic carboxylic acid having 8 to 20 carbon atoms.

[0055] In this case, the desired proportion of polyesters formed from polyols and aliphatic carboxylic acids having 8 to 20 carbon atoms may already be present in the unprocessed corn wax, but it can also be adjusted by pretreatment of the corn wax. Preferably, the proportion is already present in the unprocessed corn wax (MW). In this case, it is preferable not to pretreat the corn wax (MW).

[0056] On the other hand, if the proportion of the polyester formed from the polyol and the aliphatic carboxylic acid having 8 to 20 carbon atoms is significantly greater than 25% by weight, it may be advantageous to pretreat the corn wax (MW) before providing it in step i). In this case, it is advantageous that the pretreatment does not include the saponification of the esters present in the corn wax (MW).

[0057] Instead, the polyester formed from a polyol and an aliphatic carboxylic acid having 8 to 20 carbon atoms is preferably extracted with one or more organic solvents, wherein the extraction is carried out until the desired ratio of the polyol and the aliphatic carboxylic acid having 8 to 20 carbon atoms is achieved. Any organic solvent capable of dissolving oils and fats, such as ethyl acetate or acetone, preferably ethyl acetate, is suitable for this purpose.

[0058] Polyesters formed from polyols and aliphatic carboxylic acids having 8 to 20 carbon atoms are preferably diglycerides and triglycerides of aliphatic carboxylic acids having 8 to 20 carbon atoms, especially oils naturally found in corn, particularly corn oil.

[0059] Therefore, extraction with organic solvents can be a deoiling process. In this case, the ratio of polyols and aliphatic carboxylic acids having 8 to 20 carbon atoms can also be referred to as the oil content of the corn wax.

[0060] Preferably, the corn wax (MW), regardless of the ratio of polyols and aliphatic carboxylic acids having 8 to 20 carbon atoms in its unprocessed state, is not pretreated by saponification at any time before oxidation.

[0061] Preferred corn wax (MW) comprises a mixture of linear esters having a number-average total carbon chain length of 45 to 55 atoms, preferably 47 to 53 carbon atoms. More preferably, corn wax (MW) comprises a mixture of linear esters wherein at least 30% by mass, preferably at least 40% by mass, and more preferably at least 50% by mass of the linear ester mixture has a total carbon chain length of no more than 52 carbon atoms, preferably 40 to 52 carbon atoms.

[0062] Furthermore, the corn wax (MW) preferably has an acid value of less than 20 mg KOH / g, more preferably less than 15 mg KOH / g, more preferably less than 10 mg KOH / g, and particularly preferably 1 to 8 mg KOH / g. The corn wax (MW) also preferably has a saponification value of less than 150 mg KOH / g, more preferably less than 120 mg KOH / g, more preferably 30 to 100 mg KOH / g, and particularly preferably 60 to 95 mg KOH / g.

[0063] The mixture (M) formed from chromium trioxide and sulfuric acid provided in step ii) can be any mixture, provided that it is capable of oxidizing the oxidizable components of corn wax. Such mixtures formed from chromium trioxide and sulfuric acid are often also referred to as chromium sulfuric acid. The sulfuric acid is preferably concentrated sulfuric acid having a sulfuric acid content of at least 90% by weight, preferably at least 96% by weight, and more preferably at least 99% by weight. This may optionally be fuming sulfuric acid, i.e., it additionally contains sulfur trioxide. The concentration of chromium trioxide in the mixture (M) is preferably 50 to 200 g / L, more preferably 70 to 150 g / L, and most preferably 80 to 120 g / L.

[0064] In step iii) of the method of the present invention, the corn wax (MW) is oxidized by reacting it with the mixture (M) to obtain corn wax oxide (O). The reaction is preferably carried out with stirring and at a temperature of 70 to 200°C, more preferably 80 to 150°C, more preferably 90 to 140°C, and particularly preferably 105 to 130°C.

[0065] The total weight ratio of chromium trioxide to corn wax (MW) used is preferably 1:6 to 3:1, especially 1:5 to 2:1, and more preferably 2:5 to 6:5. If the ratio is less than 1:6, the degree of oxidation is too small to significantly lighten the color of the corn wax. If the ratio is greater than 3:1, the ester bond breaking occurs to a particularly high degree, making it difficult to maintain the desired acid value in the product, depending on other conditions. If step vii) of the method of the invention is carried out, the weight ratio of chromium trioxide to corn wax (MW) used is preferably less than 6:5 in each implementation of step iii).

[0066] This step iii) may optionally be divided into two or more steps. For example, step iii) may include initially adding the mixture (M) and subsequently adding the corn wax (MW). Alternatively, step iii) may include initially adding the corn wax (MW) and subsequently adding the mixture (M). In these cases, the addition of the respective second component (MW) or (M) may be carried out, for example, in portions, continuously or all at once, preferably in portions or continuously, more preferably in portions.

[0067] In an embodiment in which the reaction in step iii) is carried out at a temperature of 70 to 200°C, the temperature of the corn wax (MW) and / or the mixture (M) during the addition process may optionally be different from the reaction temperature, and is adjusted to a desired value of preferably 70 to 200°C, more preferably 80 to 150°C, more preferably 90 to 140°C, and particularly preferably 105 to 130°C only after the second component has been added.

[0068] For example, the temperature during the addition process can be between 60 and 150°C, preferably between 70 and 130°C, and more preferably between 80 and 110°C. Preferably, the corn wax (MW) is in molten form during the addition process.

[0069] In one embodiment, the provided mixture (M) of chromium trioxide and sulfuric acid is initially added and heated to a temperature of 60 to 150°C, preferably 70 to 130°C, more preferably 80 to 110°C, and the corn wax (MW) is added in portions in a solid state. After the addition is complete, the temperature is adjusted to 70 to 200°C, preferably 80 to 150°C, preferably 90 to 140°C, more preferably 105 to 130°C, and the oxidation is carried out.

[0070] In another embodiment, the provided mixture (M) of chromium trioxide and sulfuric acid is initially added and heated to a temperature of 60 to 130°C, and the corn wax (MW) is added in portions in a molten state, preferably at a temperature of 60 to 150°C, more preferably 70 to 130°C, and even more preferably 80 to 110°C. After the addition is complete, the temperature is adjusted to 70 to 200°C, preferably 80 to 150°C, more preferably 90 to 140°C, and even more preferably 105 to 130°C, and the oxidation is carried out.

[0071] In another embodiment, the corn wax (MW) is initially added and melted at a temperature of 60 to 150°C, preferably 70 to 130°C, more preferably 80 to 110°C, and the mixture (M) formed from chromium trioxide and sulfuric acid is added in portions in an untemperatured state. After the addition is complete, the temperature is adjusted to 70 to 200°C, preferably 80 to 150°C, preferably 90 to 140°C, more preferably 105 to 130°C, and the oxidation is carried out.

[0072] In another embodiment, the corn wax (MW) is initially added and melted at a temperature of 60 to 150°C, preferably 70 to 130°C, more preferably 80 to 110°C, and the mixture (M) formed from chromium trioxide and sulfuric acid is added in portions in a hot state, preferably at a temperature of 60 to 150°C, preferably 70 to 130°C, more preferably 80 to 110°C. After the addition is complete, the temperature is adjusted to 70 to 200°C, preferably 80 to 150°C, preferably 90 to 140°C, more preferably 105 to 130°C, and the oxidation is carried out.

[0073] In another embodiment, corn wax (MW) and a mixture (M) formed from chromium trioxide and sulfuric acid are initially added together at room temperature and gradually heated to a temperature of 70 to 200°C, preferably 80 to 150°C, more preferably 90 to 140°C, and more preferably 105 to 130°C, and the oxidation is carried out at this temperature.

[0074] Oxidation at at least 70 to 200°C, 80 to 150°C, 90 to 140°C, or 105 to 130°C, preferably with the addition of the corn wax (MW) and / or the mixture (M) carried out under stirring. Here, the stirring can be carried out in any desired manner, such as using a mechanically driven stirrer or a magnetically driven stirrer. Preferably, the stirring is carried out with a mechanically driven stirrer, more preferably with a mechanically driven stirrer comprising a precision glass (KPG) stirrer.

[0075] The stirring speed in step iii) is preferably in the range of 100 to 500 rpm, more preferably 120 to 300 rpm, and most preferably 170 to 250 rpm, because at stirring speeds below 100 rpm, the mixing required for effective oxidation may not be provided, while at stirring speeds above 500 rpm, the risk of forming an emulsion that may not be able to be separated increases.

[0076] The oxidation of corn wax in step iii) is preferably carried out over a period of at least 30 minutes, more preferably 45 minutes to 12 hours, even more preferably 1 to 8 hours, preferably 2 to 5 hours, and particularly preferably 3 to 4.5 hours.

[0077] Furthermore, it is advantageous not to add oxidation accelerators to the reaction mixture consisting of corn wax (MW) and the mixture (M), as these accelerators often lead to the cleavage of ester bonds and may therefore increase the acid value in the corn wax oxide (O).

[0078] Therefore, it is preferable not to use oxidation promoters during the oxidation process, especially not to use oxidation promoters such as emulsifiers (e.g., alkyl sulfonates, fluorinated alkyl sulfonates), surfactants, polymeric surfactants, nitrogen-containing cationic surfactants, phase transfer catalysts, Fenton reagents, metal salts, hydrochloric acid or the like.

[0079] After the desired reaction time has been reached, the reaction is terminated in step iv), and the reaction mixture is allowed to stand until the organic phase separates from the aqueous phase. "Terminate the reaction" is understood to mean stopping the stirring and terminating the heating.

[0080] At this point, the floating organic phase containing the corn wax oxide (O) begins to separate from the settling aqueous phase containing sulfuric acid and chromium compounds. Before allowing it to stand, the reaction mixture may optionally be transferred to an apparatus in which the organic phase can be more easily separated from the aqueous phase after separation. An example of such an apparatus is a separatory funnel. Other apparatuses for this purpose are known to those skilled in the art and may be used herein.

[0081] The time required to obtain the phase boundary depends on the acid value. Surprisingly, with the method of the present invention, it was observed that the organic phase and the aqueous phase separated by a clear phase boundary shortly after "terminating the reaction" in step iv). At acid values ​​in the range of 20-50 mg KOH / g, a clear phase boundary was observed within a separation time of less than 1 minute. At acid values ​​>50 mg KOH / g, this occurred within a few seconds.

[0082] Even at very low acid values ​​of approximately 10 mg KOH / g, phase boundaries are observed after the "reaction is terminated," which is quite atypical for waxes oxidized by chromium sulfide. For example, using the described synthesis process, under otherwise identical conditions, phase boundaries are only observed for rice wax at acid values ​​above approximately 20 mg KOH / g, and for lignite wax only at acid values ​​above approximately 50 mg KOH / g. This is a clear advantage of corn wax oxide (O) compared to oxides of other natural waxes from both economic and environmental perspectives.

[0083] In step v), the organic phase containing the corn wax oxide is separated. This can be done, for example, by using a separatory funnel. Alternatively, the floating organic phase can be skimmed off using appropriate techniques.

[0084] The organic phase can also be poured out through the edge of the container. The method of separating the organic phase from the aqueous phase after phase separation is known in principle to those skilled in the art and can be used herein.

[0085] Alternatively, in step vi), the separated organic phase containing the corn wax oxide may be further post-treated to remove residues containing chromium compounds from the organic phase, thereby obtaining a purified form of the corn wax oxide.

[0086] The post-processing can be performed in any manner suitable for separating polar and / or water-soluble substances from organic matter. For example, the organic phase can be purified by chromatography or filtered through silica gel.

[0087] The residues containing chromium compounds are preferably removed by washing the organic phase with an aqueous solution of oxalic acid and / or sulfuric acid. Alternatively, the residues containing chromium compounds can be preferably removed by washing the organic phase with water. Alternatively, the residues containing chromium compounds can be preferably removed by centrifuging the organic phase.

[0088] Here, “washing” is understood in each case to mean mixing the organic phase with the corresponding washing medium, followed by phase separation according to steps iv) and v).

[0089] In a preferred embodiment, the residue containing chromium compounds is removed by washing the organic phase once or multiple times with an aqueous solution of oxalic acid and sulfuric acid, followed by washing the organic phase once or multiple times with water.

[0090] In another preferred embodiment, the residue containing chromium compounds is removed by washing the organic phase once or multiple times with an aqueous solution of oxalic acid and sulfuric acid, followed by centrifugation of the organic phase.

[0091] In another preferred embodiment, the residue containing chromium compounds is removed by washing the organic phase once or multiple times with water, followed by centrifugation of the organic phase.

[0092] In a particularly preferred embodiment, the residue containing chromium compounds is removed by washing the organic phase once or multiple times with an aqueous solution of oxalic acid and sulfuric acid, followed by washing the organic phase once or multiple times with water, and then centrifuging the organic phase.

[0093] Optionally, in step vii), the sequence of steps ii) to vi) may be repeated using the optionally purified form of corn wax oxide (O) instead of corn wax (MW). Preferably, the sequence of steps ii) to vi) is not repeated.

[0094] In a preferred embodiment, the method of the present invention is a method for preparing corn wax oxide (O), the method comprising the following steps:

[0095] (i) Provide corn wax (MW), preferably deoiled corn wax (MW);

[0096] (ii) Provide a mixture (M) formed of chromium trioxide and sulfuric acid;

[0097] (iii) Oxidation of corn wax (MW) is carried out by stirring the corn wax (MW) and the mixture (M) at a temperature of 70 to 200°C, preferably 80 to 150°C, preferably 90 to 140°C, and more preferably 105 to 130°C, to obtain corn wax oxide (O).

[0098] (iv) Terminate the reaction and allow the reaction mixture obtained in step iii) to stand until the organic phase separates from the aqueous phase;

[0099] (v) Separate the organic phase;

[0100] (vi) Optionally, residues containing chromium compounds are removed from the organic phase to obtain a purified form of corn wax oxide (O);

[0101] (vii) Optionally, the sequence of steps ii) to vi) is repeated using the corn wax oxide (O) optionally in a purified form instead of the corn wax (MW).

[0102] The oxidation in step iii) is carried out for at least 30 minutes, preferably 45 minutes to 12 hours, more preferably 1 to 8 hours, preferably 2 to 5 hours, and particularly preferably 3 to 4.5 hours.

[0103] In this implementation, iodine color values ​​less than 6, typically less than 5, such as less than 2, as measured according to DIN 6162 (2014), and / or yellowness indices less than 40, typically less than 30, such as less than 15, as measured according to ASTM E 313-20, can be achieved in a particularly selective manner.

[0104] The present invention further provides a corn wax oxide (O), which is obtained by reacting corn wax (MW) with a mixture (M) formed from chromium trioxide and sulfuric acid. The corn wax oxide (O) preferably has an acid value greater than that of the corn wax (MW) used.

[0105] Preferably, the corn wax oxide (O) of the present invention has an acid value of about 10 to about 170 mg KOH / g, more preferably 10 to 140 mg KOH / g, more preferably 11 to 130 mg KOH / g, and even more preferably 15 to 110 mg KOH / g, as measured according to ISO 2114 (2002). In one embodiment, the corn wax oxide (O) of the present invention has an acid value of about 10 to less than 20 mg KOH / g.

[0106] In one alternative embodiment, the corn wax oxide (O) of the present invention has an acid value of about 20 to about 50 mg KOH / g. In another alternative embodiment, the corn wax oxide (O) of the present invention has an acid value of from greater than 50 to about 170 mg KOH / g, as measured according to ISO 2114 (2002). In yet another embodiment, the corn wax oxide (O) of the present invention has an acid value of less than 140 mg KOH / g, preferably less than 110 mg KOH / g, more preferably less than 60 mg KOH / g, particularly preferably less than 40 mg KOH / g, and especially preferably less than 20 mg KOH / g.

[0107] Depending on the degree of reaction of the ester, the corn wax oxide of the present invention contains natural esters (C42-C60). Here, "natural esters" is understood to mean the residual fraction of wax esters initially contained in the crude wax that is not covered by the reaction.

[0108] The present invention further provides a corn wax oxide (O) having an acid value of about 10 to about 170 mg KOH / g as measured according to ISO 2114 (2002), wherein the weight ratio of a natural wax ester having 46 carbon atoms to the weight ratio of a natural wax ester having 52 carbon atoms is greater than 1. This corn wax oxide (O) can be prepared by the method claimed in claim 1.

[0109] Preferably, the corn wax oxide (O) of the present invention is characterized in that the acid value of the corn wax oxide (O) is greater than the acid value of the corn wax (MW).

[0110] Furthermore, the corn wax oxide (O) of the present invention, especially when prepared by the method claimed in claim 1, preferably has an iodine color value of less than 6, more preferably less than 5, even more preferably less than 3, preferably less than 2, and especially preferably less than 1.5 (measured according to DIN 6162 (2014)). Alternatively, the corn wax oxide (O) of the present invention preferably has a yellowness index of less than 50, more preferably less than 30, even more preferably less than 20, preferably less than 15, and especially preferably less than 10 (measured according to ASTM E313-20).

[0111] Furthermore, the corn wax oxide (O) of the present invention preferably has a proportion of less than 5% by weight, more preferably less than 3% by weight, and most preferably less than 1% by weight of a polyester formed from a polyol and an aliphatic carboxylic acid having 8 to 20 carbon atoms, based on the total weight of the corn wax oxide (O).

[0112] In one embodiment, the corn wax oxide (O) comprises:

[0113] a) 3% to 40% by weight of free aliphatic carboxylic acids having 8 to 36 carbon atoms, based on the total weight of the corn wax oxide (O);

[0114] b) 0% to 10% by weight of free aliphatic alcohols having 24 to 36 carbon atoms, based on the total weight of the corn wax oxide (O);

[0115] c) 0% to 5% by weight of free aliphatic dicarboxylic acids having 10 to 30 carbon atoms, based on the total weight of the corn wax oxide (O);

[0116] d) 30% to 97% by weight of natural esters having 40 to 66 carbon atoms, based on the total weight of the corn wax oxide (O); and

[0117] e) From 0% to 30% by weight of other natural components present in corn wax, based on the total weight of the corn wax oxide (O).

[0118] Wherein, based on the total weight of the corn wax oxide (O), the sum of a), b), c), d), and e) is 100% by weight.

[0119] In a preferred embodiment, the corn wax oxide (O) comprises:

[0120] a) 3% to 15% by weight of free aliphatic carboxylic acids having 8 to 36 carbon atoms, based on the total weight of the corn wax oxide (O);

[0121] b) 0% to 7% by weight of free aliphatic alcohols having 24 to 36 carbon atoms, based on the total weight of the corn wax oxide (O);

[0122] c) 0% to 4% by weight of free aliphatic dicarboxylic acids having 10 to 30 carbon atoms, based on the total weight of the corn wax oxide (O);

[0123] d) 65% to 97% by weight of a natural ester having 40 to 66 carbon atoms, based on the total weight of the corn wax oxide (O); and

[0124] e) 0% to 15% by weight of other natural components present in corn wax, based on the total weight of the corn wax oxide (O).

[0125] Wherein, based on the total weight of the corn wax oxide (O), the sum of a), b), c), d), and e) is 100% by weight.

[0126] In a preferred embodiment, the corn wax oxide (O) comprises:

[0127] a) 3% to 10% by weight of free aliphatic carboxylic acids having 8 to 36 carbon atoms, based on the total weight of the corn wax oxide (O);

[0128] b) 0% to 5% by weight of free aliphatic alcohols having 24 to 36 carbon atoms, based on the total weight of the corn wax oxide (O);

[0129] c) 0% to 3% by weight of free aliphatic dicarboxylic acids having 10 to 30 carbon atoms, based on the total weight of the corn wax oxide (O);

[0130] d) 75% to 97% by weight of natural esters having 40 to 66 carbon atoms, based on the total weight of the corn wax oxide (O); and

[0131] e) 0% to 15% by weight of other natural components present in corn wax, based on the total weight of the corn wax oxide (O).

[0132] Wherein, based on the total weight of the corn wax oxide (O), the sum of a), b), c), d), and e) is 100% by weight.

[0133] The present invention also provides a corn wax oxide (O) having an acid value of less than 50 mg KOH / g and a proportion of less than 5% by weight based on the total weight of the corn wax oxide (O) of a polyester formed from a polyol and an aliphatic carboxylic acid having 8 to 20 carbon atoms, comprising:

[0134] a) 3% to 25% by weight of free aliphatic carboxylic acids having 8 to 36 carbon atoms, based on the total weight of the corn wax oxide (O);

[0135] b) 0% to 10% by weight of free aliphatic alcohols having 24 to 36 carbon atoms, based on the total weight of the corn wax oxide (O);

[0136] c) 0% to 5% by weight of free aliphatic dicarboxylic acids having 10 to 30 carbon atoms, based on the total weight of the corn wax oxide (O);

[0137] d) 50% to 97% by weight of natural esters having 40 to 66 carbon atoms, based on the total weight of the corn wax oxide (O); and

[0138] e) 0% to 15% by weight of other natural components present in corn wax, based on the total weight of the corn wax oxide (O).

[0139] Wherein, based on the total weight of the corn wax oxide (O), the sum of a), b), c), d), and e) is 100% by weight.

[0140] Preferably, the content of lignin present in the corn wax oxide (O) is no more than 5% by weight based on the total weight of the corn wax oxide (O), more preferably no more than 3% by weight.

[0141] The weight ratio and chain length distribution can be measured, for example, by gas chromatography.

[0142] Furthermore, the corn wax oxide of the present invention typically has a dropping point between 70°C and 90°C, preferably between 75°C and 80°C, as measured according to DIN ISO 2176 (1997).

[0143] The corn wax oxide of the present invention preferably has a particle size of less than 10 mm as measured according to DIN 51579 (2010). -1 Preferably less than 6mm -1 More preferably less than 4mm -1 The optimal size is less than 3mm. -1 The penetration index (NPZ).

[0144] The oxidation of the corn wax preferably increases the saponification value, as measured according to DIN ISO 3681 (2019), by no more than 70%, preferably no more than 40%, and more preferably no more than 30%. The increase in saponification value can be explained mechanistically by the cleavage of the wax ester and the subsequent oxidation of the wax alcohol to acid. Furthermore, some unsaturated carbon-carbon bonds are cleaved by the oxidizing agent and are also oxidized to acid.

[0145] Therefore, the saponification value is also a measure of actual oxidation that has occurred, which differs from saponification where the saponification value is known to remain unchanged, and from other bleaching methods where only the product color is lightened. For example, bleaching corn wax with hydrogen peroxide is not a chemical modification of the wax in the sense of this invention, because it only removes discoloration impurities and minor components without altering the actual wax structure.

[0146] The corn wax oxide (O) of the present invention is characterized by particularly good thermal stability as measured according to DIN 51006 (2005), wherein the mass loss up to 300°C (heating rate: 5°C / min) is less than 50%, preferably less than 20%, more preferably less than 10%.

[0147] The present invention further provides an esterified corn wax oxide (E), which is prepared by esterifying the corn wax oxide (O) with an alcohol or by reacting the corn wax oxide (O) with an alcohol. Preferred alcohols are polyols, such as ethylene glycol, butanediol, glycerol, diglycerol, trimethylolpropane, pentaerythritol, or sorbitol. In the esterification process, the weight ratio of alcohol to corn wax oxide (O) is preferably selected to be from 1:100 to 1:5, more preferably from 1:50 to 1:10, and most preferably from 1:20 to 1:12.

[0148] In addition to a renewable raw material base, the esterified product is preferably characterized by particularly good thermal stability as measured according to DIN 51006 (2005), wherein the mass loss up to 300°C (heating rate: 5°C / min) is less than 15%, preferably less than 10%. Preferably, the esterified product has an acid value of less than 40 mg KOH / g, more preferably less than 30 mg KOH / g, and most preferably less than 20 mg KOH / g. The present invention also provides the use of the corn wax oxide (O) of the present invention, or the saponified corn wax oxide (V) of the present invention, or the esterified corn wax oxide (E) of the present invention for agricultural or forestry purposes, as an additive in plastics processing, in care products, in printing inks, and / or in paints.

[0149] The present invention further provides a saponified corn wax oxide (V), which is prepared by saponifying the above-mentioned corn wax oxide (O) or the above-mentioned esterified corn wax oxide (E) with an alkaline metal salt or an aqueous alkaline solution (e.g., NaOH, KOH, etc.). The alkaline metal salt is selected from metal hydroxides (e.g., NaOH, KOH, Ca(OH)2, Zn(OH)2, etc.), metal oxides (e.g., CaO, etc.), and metal carbonates (e.g., Na2CO3, CaCO3, etc.). Alkali metal hydroxides and / or alkaline earth metal hydroxides are preferred, especially NaOH, KOH, and / or Ca(OH)2. Ca(OH)2 is particularly preferred.

[0150] During the saponification process, the weight ratio of the alkaline metal salt to corn wax oxide (O) is preferably selected to be 1:100 to 1:5, more preferably 1:50 to 1:10.

[0151] The corresponding preparation procedure can be found, for example, in DE4019167 or EP1010728. In addition to the aforementioned renewable raw material base, the saponified product is preferably characterized by particularly good thermal stability as measured according to DIN 51006 (2005), wherein the mass loss up to 300°C (heating rate: 5°C / min) is less than 10%, preferably less than 5%. Preferably, the saponified product has an acid value of less than 40 mg KOH / g, more preferably less than 25 mg KOH / g, and most preferably less than 15 mg KOH / g.

[0152] The present invention also provides the use of corn wax (MW) for preparing natural wax oxides by oxidation with a mixture (M) formed of chromium trioxide and sulfuric acid. Detailed Implementation

[0153] Through the following examples, Figure 1-3 The invention is described in more detail in the claims.

[0154] Material characterization

[0155] The standard methods detailed in Table 1, which are also used to characterize lignite wax and lignite wax derivatives, are used to determine the characteristic values ​​of corn wax, corn wax oxides and other corn wax derivatives.

[0156] Table 1

[0157]

[0158] The chain length distribution of the components of the corn wax oxide was determined by gas chromatography. The comparative substances used were wax acids and wax alcohols with carbon chain lengths between C6 and C36.

[0159] C44 to C58 wax esters were prepared by combining model substances. To identify peaks in the gas chromatogram of the corn waxes, a defined amount of each individual component was added to the wax sample in each case, and a significant increase in the corresponding peak area was observed. Measurement conditions are shown in Table 2.

[0160] Table 2

[0161]

[0162] The raw materials used were two different corn waxes (MW 1-2) used as embodiments of the present invention, and two rice bran waxes (RBW 1-2), one sugarcane wax (ZRW), and one carnauba wax (CW) used as comparative examples, all in their unprocessed state (Rohzustand). The properties of the corn waxes and comparative waxes in their unprocessed state are shown in Table 3.

[0163] The selected rice bran waxes are those whose acid value, saponification value, and oil content fall between those of the corn waxes used. Sugarcane wax and carnauba wax naturally have higher acid values ​​than corn wax or rice bran wax.

[0164] Table 3 (Methods, abbreviations, and units from Table 1)

[0165]

[0166] *Comparative Example

[0167] Examples 1 to 8 and Comparative Examples 9 to 15

[0168] Initially, chromium trioxide (concentration: 100 g CrO3 / L) in 96% sulfuric acid was added to a 3 L reaction vessel equipped with a stirrer, temperature sensor, dropping funnel, and reflux condenser, and heated to 100 °C. Molten (90 °C) unprocessed natural wax was then added in portions. The temperature of the reaction mixture was adjusted to 110 °C, and the reaction mixture was stirred at approximately 200 rpm for 4 hours using a precision glass stirrer. Heating and stirring were then stopped. Once phase separation had occurred, the aqueous phase was separated. This operation was performed twice in Examples 3 and 7, and three times in Example 8. In Examples 9, 10, 12, 14, and 15 (Comparative Examples), no phase separation occurred. Therefore, the properties of the natural wax oxide could not be studied.

[0169] Chromium residues in the organic phase were removed by washing with an aqueous solution of oxalic acid and sulfuric acid, followed by washing with water, draining into warm centrifuge tubes, and centrifuging. The oxidation conditions and properties of corn wax oxides are reported in Table 4.

[0170] Figure 1 The diagram shows the chain length distribution measured for Example 2, and in Figure 2 The diagram shows the chain length distribution measured for Example 7, where free acids are illustrated by unfilled columns and esters by filled columns.

[0171] The chain length distribution of the esters in the corn wax used (unfilled column) is as follows: Figure 3 The data shows that the number-average chain length was determined to be 50 carbon atoms.

[0172] In comparison, Figure 3 The chain length distribution of rice bran wax, with a number-average chain length of 53 carbon atoms (filled bars), is also shown. In each case, the carbon chain length is plotted on the x-axis, and the proportion of each carbon chain length in the total chain length distribution (expressed as mass%) is plotted on the y-axis, which in each case is determined by the peak area in the gas chromatogram.

[0173] As can be seen from Examples 1 to 8, the corn wax oxide has a light inherent color, an iodine color value of less than 5, and a yellowness index of less than 30. Meanwhile, the achieved acid value is within a wide range, from a very low value of 11 mg KOH / g to a high value of 128 mg KOH / g.

[0174] Conversely, in comparative examples 9, 10, 12, 14, and 15, in which rice bran wax, sugarcane wax, and carnauba wax were used, no phase separation occurred, and therefore it was impossible to separate the products. This is surprising because the acid value, saponification value, oil content, and amount of the natural waxes used for comparison purposes are close to the corresponding values ​​of the corn wax used.

[0175] In Comparative Examples 11 and 13, although phase separation was observed, in the case of rice bran wax, despite a relatively low oil content (4.3 wt%) and a relatively high product acid value (35 mg KOH / g), phase separation lasted for 300 minutes (5 hours). At acid values ​​similar to those of rice bran wax oxide (27 or 36 mg KOH / g), phase separation occurred much faster in Examples 4 and 5, despite a significantly higher oil content (9.7 wt%) in corn wax. In the case of sugarcane wax, despite a relatively high product acid value (47 mg KOH / g), it took 10 minutes until phase separation. In the case of carnauba wax, no phase separation was observed at all.

[0176] Meanwhile, much better iodine color value and yellowness index were observed in corn wax oxide.

[0177] Table 4:

[0178]

[0179] *Comparative Example

[0180] Table 4 (continued):

[0181]

[0182] *Comparative Example

[0183] Table 4 (continued):

[0184]

[0185] Therefore, compared with the cases of rice bran wax, sugarcane wax or carnauba wax, the chromium sulfate oxidation of corn wax (MW) can produce a wider range of natural wax oxides with high quality.

[0186] Examples 16 to 19:

[0187] In a 1L reaction vessel equipped with a stirrer, temperature sensor, dropping funnel, and reflux condenser, corn wax oxides obtained from Examples 3, 5, 6, and 7 were melted under a nitrogen atmosphere and mixed with the amounts of Ca(OH)₂ given in Table 5. The reaction mixture was stirred until the given acid value was reached, and then the reaction mixture was pressure filtered while hot.

[0188] Table 5

[0189]

[0190] As can be seen from Examples 16 to 19, saponification of the corn wax oxide with Ca(OH)2 enables the preparation of saponified products with a low acid value of less than 15 mg KOH / g, which is particularly suitable for applications requiring high thermal stability.

[0191] Examples 20 to 22

[0192] In a 1L reaction vessel equipped with a stirrer, temperature sensor, dropping funnel, and reflux condenser, corn wax oxide obtained from Example 7 was melted under a nitrogen atmosphere and mixed with alcohol in the amounts given in Table 6 and with 0.1g of methanesulfonic acid. The reaction mixture was stirred until a given acid value was reached, the water formed was removed by distillation, and then the reaction mixture was pressure filtered while hot.

[0193] Table 6

[0194]

[0195] As can be seen from Examples 20 to 22, esterification of the corn wax oxide with ethylene glycol, glycerol or pentaerythritol makes it easy to prepare esterified products with low acid values ​​of less than 20 mg KOH / g, which are particularly suitable for applications requiring high thermal stability.

Claims

1. A method for preparing corn wax oxide (O), the method comprising the following steps: i) Provide corn wax (MW); ii) Provide a mixture (M) formed from chromium trioxide and sulfuric acid; iii) Oxidize the corn wax (MW) by reacting it with the mixture (M) to obtain corn wax oxide (O). iv) Terminate the reaction and allow the reaction mixture obtained in step iii) to stand until the organic phase separates from the aqueous phase; v) Separate the organic phase; vi) Optionally, remove the residue containing chromium compounds from the organic phase to obtain a purified form of corn wax oxide (O). vii) Optionally, repeat the sequence of steps ii) to vi) using corn wax oxide (O) in a purified form instead of corn wax (MW); The corn wax oxide (O) therein has an increased acid value compared to the starting material.

2. The method according to claim 1, wherein no other wax is used except for corn wax.

3. The method according to claim 1 or 2, wherein the total weight ratio of chromium trioxide used to corn wax (MW) used is 1:6 to 3:

1.

4. The method according to claim 1 or 2, wherein the process of removing the residue containing the chromium compound according to step vi) is carried out, and the process includes at least one of steps via), vib), and vic): (via) Wash the organic phase with an aqueous solution of oxalic acid and / or sulfuric acid; vib) Wash the organic phase with water; (vic) Centrifuge to separate the organic phase.

5. The method according to claim 4, wherein the process of removing the residue containing the chromium compound according to step vi) includes at least two of steps via), vib), and vic).

6. The method according to claim 4, wherein the process of removing the residue containing the chromium compound according to step vi) comprises all of steps via), vib), and vic).

7. The method according to claim 1 or 2, wherein the corn wax (MW) has a content of up to 25% by weight of a polyester formed from a polyol and an aliphatic carboxylic acid having 8 to 20 carbon atoms.

8. The method according to claim 1 or 2, wherein the sulfuric acid is concentrated sulfuric acid having a sulfuric acid content of at least 90% by weight.

9. The method according to claim 1 or 2, wherein the reaction in step iii) is carried out while stirring and at a temperature of 70 to 200°C.

10. The method according to claim 1 or 2, wherein the concentration of chromium trioxide in the mixture (M) is 50 to 200 g / L.

11. The method according to claim 1 or 2, wherein the oxidation in step iii) is carried out over a period of at least 30 minutes.

12. The method of claim 11, wherein the oxidation in step iii) is carried out over a period of 1 to 8 hours.

13. The method of claim 11, wherein the oxidation in step iii) is carried out over a period of 2 to 5 hours.

14. The method of claim 11, wherein the oxidation in step iii) is carried out over a period of 3 to 4.5 hours.

15. The method according to claim 1 or 2, wherein the corn wax (MW) has an acid value of less than 20 mg KOH / g as measured according to ISO 2114 (2002).

16. A corn wax oxide (O) obtained by reacting corn wax (MW) with a mixture (M) formed from chromium trioxide and sulfuric acid, wherein the corn wax oxide has an acid value of 10 to 170 mg KOH / g as determined according to ISO 2114 (2002).

17. The corn wax oxide (O) according to claim 16, obtained by the method according to any one of claims 1 to 15.

18. The corn wax oxide (O) according to claim 16 or 17, wherein the weight ratio of the natural ester having 46 carbon atoms to the weight ratio of the natural ester having 52 carbon atoms is greater than 1.

19. An esterified corn wax oxide (E) obtained by reacting corn wax oxide (O) according to any one of claims 16 to 18 with an alcohol.

20. The esterified corn wax oxide (E) according to claim 19, wherein the alcohol is a polyol.

21. The esterified corn wax oxide (E) according to claim 19, wherein the alcohol is ethylene glycol, butanediol, glycerol, diglycerol, trimethylolpropane, pentaerythritol, or sorbitol.

22. A saponified corn wax oxide (V) obtained by saponifying the corn wax oxide (O) according to any one of claims 16 to 18 or the esterified corn wax oxide (E) according to any one of claims 19 to 21 with an alkaline metal salt, an alkali metal hydroxide and / or an alkaline earth metal hydroxide.

23. The saponified corn wax oxide (V) according to claim 22, wherein the alkaline earth metal hydroxide is Ca(OH)2.

24. The corn wax oxide (O) according to claim 17 or 18, the saponified corn wax oxide (V) according to claim 22 or 23, or the esterified corn wax oxide (E) according to any one of claims 19-21, for agricultural or forestry purposes, as an additive in plastics processing, in care products, in printing inks, and / or in paints.

25. Corn wax (MW) is used to prepare natural wax oxides by oxidation with a mixture (M) formed of chromium trioxide and sulfuric acid.

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