Amide wax and preparation method thereof

Abstract

The present invention provides an amide wax and a preparation method thereof. The preparation method comprises: placing oxidized Fischer-Tropsch wax as a first raw material in a reaction device, adding a water-carrying agent to mix with the first raw material in an inert gas atmosphere, heating until the first raw material is melted and the water-carrying agent is boiling and refluxed, dripping a second raw material, continuing the reaction for 1 to 10 hours after the dripping is completed, separating the water-carrying agent, and obtaining an amide wax product; wherein the second raw material is selected from any one or more of diamines and alcoholamine compounds. The present application uses oxidized Fischer-Tropsch wax as a raw material, introduces a more polar amide group into the Fischer-Tropsch wax, and obtains a product with a low acid value and a high amine value, so that it has a higher polarity, and has better emulsification, pigment dispersibility and oil holding properties. On the other hand, the amide wax prepared by this method overcomes the problems of lower melting point, reduced hardness, and easy precipitation in high temperature weather after oxidation of Fischer-Tropsch wax, which can meet the different needs of downstream products and improve the economic added value of Fischer-Tropsch wax production.

Description

Technical Field

[0001] The invention relates to the technical field of amide wax, and in particular to an amide wax and a preparation method thereof. Background Art

[0002] Fischer-Tropsch wax is a hydrocarbon product with a carbon number of 18 to 100 and mainly normal hydrocarbons, which is synthesized by using CO+H2 under the action of catalysts such as Fe and Co. Fischer-Tropsch wax has the characteristics of low sulfur, low nitrogen, and low aromatic content. It can be divided into high melting point, medium melting point, and low melting point wax according to the drop melting point. The drop melting point <80℃ is a medium-low melting point Fischer-Tropsch wax, which can replace paraffin in the fields of candles, emulsified wax, packaging wax, rubber protective wax, etc. The drop melting point ≥80℃ is a high melting point Fischer-Tropsch wax, which is mainly used in PVC processing, ink coatings, and rubber protection. It can replace natural animal and plant waxes and polyethylene wax. After oxidation, polar groups such as -OH, -COOH, -CHO, -COC-, and -COOR are introduced into the non-polar groups of the alkane group. Therefore, the structure of the internal chain of the oxidized wax and the properties of the surface have changed, resulting in a lower drop melting point and hardness of the Fischer-Tropsch wax. It is easy to precipitate in high temperature weather, so that some of its properties such as drop melting point and hardness cannot meet special needs.

[0003] Amide wax is one of the important products of synthetic wax. It contains large molecular non-polar groups and polar groups. Therefore, it has good surface gloss, internal and external lubrication, mutual melting, anti-sticking properties, low viscosity and mobility in the melt. It has good dispersibility for fillers and pigments. It can improve the brightness and vividness of masterbatch. It has a high melting point and can be used as a lubricant, antistatic agent, anti-blocking agent, release agent, and can also be used as a moisture-proof agent for paper, a softener and waterproof agent for fibers, etc.

[0004] At present, there are three industrial production methods for fatty acids, namely, non-catalytic hydrolysis of natural oils or hydrolysis by enzymes, paraffin oxidation and α-olefin oxidation. Fatty acids produced from the hydrolysis of natural oils account for 4 / 5 of the total fatty acids. With the emphasis on ecological environment and environmental protection in countries around the world, the protection of natural forests and the ban on logging, the resource output and quality of natural oils will decline year by year, and the production and price of fatty acids will also be greatly affected. In addition, my country's natural oil resources are scarce. After oxidation, Fischer-Tropsch wax contains a large amount of long-chain and ultra-long-chain fatty acids and esters. The synthesis of its amidation modification with amines has not been reported at home and abroad. Therefore, it is of great significance to study amide wax and polyamide wax.

[0005] In the prior art, amide wax prepared from fatty acids or oxidized waxes with short carbon chains such as dodecanoic acid, tetradecanoic acid, hexadecanoic acid, and octadecanoic acid is used as raw material, and has a low drop melting point, insufficient hardness, and is easily worn during use. Fatty acids are generally expensive, and are mostly produced from paraffin oxidation, with a complex production process. In addition, as paraffin resources become increasingly scarce, the production of fatty acids will be limited.

[0006] Most of the literature uses the method of adding fatty acids, antioxidants and catalysts to react with amines to prepare amide wax. The specific process is: the fatty acid and the antioxidant are mixed, the temperature is raised to a certain temperature in an inert gas atmosphere for reaction, the temperature is lowered after the reaction is completed, and then amines and catalysts are added to continue the reaction. The reaction process is complicated and the adjustment process is troublesome, which can easily cause the product quality and indicators to be unqualified.

[0007] The patent application with publication number CN103897733A provides an amide-based wax refined by amidation of lignite wax and a preparation method thereof, using lignite wax extracted from lignite as a raw material, and reacting with an amidation reagent under the catalytic action of a strong acid. The required lignite wax is a scarce mineral, and the extraction process is complicated. A strong acid catalyst needs to be added during the amidation reaction, and the requirements for the production process and equipment manufacturing are more stringent and complex.

[0008] The patent application with application number CN201810091757 discloses an amide wax modified micronized Fischer-Tropsch wax and a preparation method thereof, wherein the Fischer-Tropsch wax powder and the amide wax are crushed, then uniformly mixed and sent to a low-temperature freezing pulverizer for crushing to obtain the amide wax modified micronized Fischer-Tropsch wax. This method belongs to physical modification, and the structure and composition of the Fischer-Tropsch wax do not change.

[0009] After oxidation, polar groups such as -OH, -COOH, -CHO, -COC-, and -COOR are introduced into the non-polar groups of the alkane groups. Therefore, the structure of the internal chain of the oxidized wax and the properties of the surface change, resulting in a decrease in the drop melting point of the Fischer-Tropsch wax, a decrease in hardness, and easy precipitation in high temperature weather, so that some of its properties such as drop melting point and hardness cannot meet special needs. At present, amide waxes on the market are all prepared from fatty acids as raw materials for amide wax products, and the carbon chains of fatty acid compounds are relatively short, generally ≤36 carbon atoms. The prepared amide wax has a low drop melting point and cannot meet the application in the fields of ink, plastic, PVC processing, etc. Moreover, fatty acids are generally expensive, and their production mostly comes from paraffin oxidation. The production process is complicated, and with the increasing shortage of paraffin resources, the production of fatty acids will be limited. In addition, the method of adding fatty acids to antioxidants and catalysts has a complicated reaction process, a troublesome adjustment process, and it is difficult to control product quality and indicators, which is prone to unqualified situations. Summary of the invention

[0010] The main purpose of the present invention is to provide an amide wax and a preparation method thereof, so as to solve the problems of high preparation cost and poor performance of the amide wax in the prior art.

[0011] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a method for preparing amide wax is provided, which comprises: placing oxidized Fischer-Tropsch wax as a first raw material in a reaction device, adding a water-carrying agent to mix with the first raw material in an inert gas atmosphere, heating until the first raw material is melted and the water-carrying agent boils and refluxes, adding a second raw material dropwise, continuing the reaction for 1 to 10 hours after the addition is completed, separating the water-carrying agent, and obtaining an amide wax product; wherein the second raw material is selected from any one or more of diamines and alcoholamine compounds.

[0012] Furthermore, the acid value of the oxidized Fischer-Tropsch wax is 15 to 30 mgKOH / g. Preferably, the saponification value of the oxidized Fischer-Tropsch wax is 35 to 110 mgKOH / g. Preferably, the drop melting point of the oxidized Fischer-Tropsch wax is 80 to 110°C.

[0013] Further, the diamine is selected from any one or more of diethylenetriamine, ethylenediamine, propylenediamine, butylenediamine, pentanediamine, hexamethylenediamine, heptanediamine, dodecanediamine and p-phenylenediamine;

[0014] Preferably, the alcoholamine compound is selected from any one or more of monoethanolamine, diethanolamine and triethanolamine.

[0015] Further, the amount of the second raw material is 1% to 10% by weight of the oxidized Fischer-Tropsch wax, preferably 3% to 6%;

[0016] Preferably, the second raw material is preheated before being added dropwise;

[0017] Preferably, the second raw material is added dropwise for 15 to 40 minutes;

[0018] Preferably, the inert gas is selected from any one or more of nitrogen and argon.

[0019] Furthermore, when the second raw material is added dropwise, the temperature of the reaction solution is 110 to 150°C. Preferably, after the second raw material is added dropwise, the reaction temperature is 110 to 150°C.

[0020] Furthermore, after the dropwise addition is completed, the reaction is continued for 1 to 3 hours.

[0021] Furthermore, the water-carrying agent is any one or more of toluene, xylene, trimethylbenzene, n-octane and n-heptane.

[0022] Furthermore, the preparation method also includes that after the water-carrying agent is heated to a boiling state, the steam of the water-carrying agent is condensed and separated by a water separator and then returned to the reaction liquid.

[0023] Furthermore, the amount of the water-carrying agent is 2 to 10 times, preferably 3 to 5 times, the weight of the oxidized Fischer-Tropsch wax.

[0024] According to another aspect of the present invention, an amide wax is provided, which is prepared by any one of the above preparation methods.

[0025] By applying the technical solution of the present invention, oxidized Fischer-Tropsch wax is used as a raw material, and a more polar amide group is introduced into the Fischer-Tropsch wax, the obtained product has a low acid value and a high amine value, so that it has a higher polarity, better emulsification, pigment dispersibility and oil retention. On the other hand, the amide wax prepared by this method overcomes the problems of lower drop melting point, reduced hardness and easy precipitation in high temperature weather after oxidation of Fischer-Tropsch wax, which can meet the different needs of downstream products and improve the economic added value of Fischer-Tropsch wax production. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0027] Figure 1 A schematic diagram of the process flow of preparing amide wax according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0028] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] As analyzed in the background technology of this application, the prior art has the problems of high preparation cost, low melting point and low hardness of amide wax. In order to solve this problem, this application provides an amide wax and a preparation method thereof.

[0030] According to a typical embodiment of the present application, a method for preparing amide wax is provided, which comprises: placing oxidized Fischer-Tropsch wax as a first raw material in a reaction device, adding a water-carrying agent to mix with the first raw material in an inert gas atmosphere, heating until the first raw material is melted and the water-carrying agent boils and refluxes, adding a second raw material dropwise, continuing the reaction for 1 to 10 hours after the addition is completed, separating the water-carrying agent, and obtaining an amide wax product; wherein the second raw material is selected from any one or more of diamines and alcoholamine compounds.

[0031] The preparation method uses oxidized Fischer-Tropsch wax as raw material, introduces a more polar amide group into the Fischer-Tropsch wax, and the product has a low acid value and a high amine value, making it more polar, and having better emulsification, pigment dispersibility and oil retention. On the other hand, the amide wax prepared by this method overcomes the problems of lower drop melting point, reduced hardness and easy precipitation in high temperature weather after oxidation of Fischer-Tropsch wax, which can meet the different needs of downstream products and improve the economic added value of Fischer-Tropsch wax production.

[0032] In the present invention, oxidized Fischer-Tropsch wax is used to prepare high-hardness amide wax, and the method is simple, easy to operate, and the raw material source is extensive and cheap, and the property of amide wax can be flexibly adjusted according to actual needs. In recent years, with the commissioning and stable operation of coal-to-oil indirect liquefaction devices such as Lu'an, Yitai, and Ningmei, the production capacity of Fischer-Tropsch wax is saturated, and the product price is relatively low. The use of oxidized Fischer-Tropsch wax to prepare high-hardness amide wax not only extends the Fischer-Tropsch wax industry chain, increases the application surface, and also expands the raw materials of amide wax. And Fischer-Tropsch wax uses CO+H2 as raw material, does not contain sulfur compounds and aromatic compounds, has no carcinogenic effect, and the generated amide wax does not contain sulfur compounds and aromatic compounds, and can be used in industrial applications such as daily necessities, light chemical industry, textiles, papermaking, and printing and dyeing.

[0033] The above-mentioned oxidized Fischer-Tropsch wax is an oxidized wax generated by oxidation of Fischer-Tropsch wax. In some embodiments of the present application, the acid value of the oxidized Fischer-Tropsch wax is 15 to 30 mgKOH / g, such as 15 mgKOH / g, 20 mgKOH / g, 25 mgKOH / g, 30 mgKOH / g or any range value therebetween. The prepared amide wax has a lower acid value and a higher amine value. In some embodiments of the present application, the saponification value of the oxidized Fischer-Tropsch wax is 35-110 mgKOH / g. Exemplarily, the saponification value of the oxidized Fischer-Tropsch wax is 40 mgKOH / g, 50 mgKOH / g, 60 mgKOH / g, 70 mgKOH / g, 80 mgKOH / g, 90 mgKOH / g, 100 mgKOH / g, 110 mgKOH / g or any range therebetween. Preferably, the saponification value of the oxidized Fischer-Tropsch wax is 50-80 mgKOH / g. If the saponification value is too low, the amide wax amine value generated by the reaction is low, the polar groups are few, the hardness is low, and it is difficult to emulsify and utilize. If the saponification value is too high, the unreacted wax is little, and the properties of the Fischer-Tropsch wax such as brightness and low viscosity cannot be well reflected. In some embodiments of the present application, the drop melting point of the oxidized Fischer-Tropsch wax is 80-110°C, for example, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C or any range therebetween. The drop melting point of the oxidized Fischer-Tropsch wax falling within the above range has better properties such as the drop melting point of the amide wax obtained by the preparation method.

[0034] The above-mentioned second raw material can react with the first raw material oxidized Fischer-Tropsch wax to generate an amide structure. Amides, diamines and alcoholamines that can carry out the reaction can be applied to the preparation method. The above-mentioned diamine mainly refers to a compound containing two amino groups. In some embodiments of the present application, the diamine is selected from any one or more of diethylenetriamine, ethylenediamine, propylenediamine, butylenediamine, pentanediamine, hexamethylenediamine, heptanediamine, dodecanediamine and p-phenylenediamine. Alcoholamine compounds can be selected from existing compounds of the same type. In some embodiments of the present application, alcoholamine compounds are selected from any one or more of monoethanolamine, diethanolamine and triethanolamine. The amidation reaction with oxidized Fischer-Tropsch wax is relatively easy to carry out and has a wide range of sources.

[0035] The feed ratio of the first raw material and the second raw material can be determined according to the stoichiometric ratio of the reaction. In some embodiments of the present application, the amount of the second raw material is 1% to 10% of the weight of the oxidized Fischer-Tropsch wax of the first raw material, preferably 3% to 6%, and the generated amide wax is more fully amidated and has better overall performance; illustratively, the amount of the second raw material is 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7% or any range between the two of the weight of the oxidized Fischer-Tropsch wax of the first raw material. In some embodiments of the present application, the second raw material is preheated before being added dropwise to prevent the temperature of the reaction solution from being reduced due to the addition of the second raw material, affecting the reaction effect. The preheating temperature can be the same as the reaction temperature, or it can be slightly higher or slightly lower than the reaction temperature.

[0036] By adding the second raw material to the reaction device in a dropwise manner, it is possible to prevent the reaction from being too fast, generating a large amount of heat in a short period of time, and causing safety hazards. In some embodiments of the present application, the second raw material is added dropwise for 15 minutes to 40 minutes. Before adding the second raw material dropwise, the gas in the reaction device is replaced with an inert gas to prevent the second raw material from being oxidized. In some embodiments of the present application, the inert gas is selected from any one or more of nitrogen and argon.

[0037] Considering the reaction speed and safety, in some embodiments of the present application, when the second raw material is added dropwise, the temperature of the reaction solution is 110-150° C., preferably, after the second raw material is added dropwise, the reaction temperature is 110-150° C. In order to allow the first raw material oxidized Fischer-Tropsch wax to fully react with the second raw material to generate an amide wax with better performance, the reaction time is continued for 1-3 hours after the second raw material is added dropwise.

[0038] The above-mentioned water-carrying agent refers to a solvent that does not participate in the amidation reaction, can carry the water generated by the reaction out of the reaction system, and promote the formation of amide wax. In some embodiments of the present application, the water-carrying agent is any one or more of toluene, xylene, trimethylbenzene, n-octane, and n-heptane.

[0039] In order to further reduce product costs and resource consumption, the water-carrying agent can be recycled. In some embodiments of the present application, the preparation method further includes that after the water-carrying agent is heated to a boiling state, the steam of the water-carrying agent is condensed and separated by a water separator and then returned to the reaction liquid. In particular, when the water-carrying agent is selected from any one of toluene and xylene or a combination of the two, it evaporates at the temperature that is conducive to the amidation reaction, takes out the water generated by the reaction, and is easy to separate from the water, thereby reducing the process difficulty.

[0040] Since the water-carrying agent needs to be continuously evaporated to remove the water generated in the system during the reaction, a certain content of the water-carrying agent needs to be maintained in the reaction device. When the water-carrying agent can be recycled into the reaction system, such as when the aforementioned circulation method is adopted, the amount of the water-carrying agent is 2 to 10 times the weight of the oxidized Fischer-Tropsch wax, preferably 3 to 5 times, which can better promote the formation of amides and improve the utilization rate of the water-carrying agent.

[0041] According to another typical embodiment of the present application, an amide wax is provided, characterized in that the amide wax is prepared by any of the above-mentioned preparation methods. The amide wax is prepared with oxidized Fischer-Tropsch wax as raw material, and a more polar amide group is introduced into the Fischer-Tropsch wax, with a low acid value, a high amine value, a higher polarity, better emulsification, pigment dispersibility and oil retention, and a lower preparation cost. Since the main raw material Fischer-Tropsch oxidized wax is derived from Fischer-Tropsch wax with CO+H2 as raw material, it does not contain sulfur compounds and aromatic compounds and has no carcinogenic effect. The prepared amide wax also does not contain sulfur compounds and aromatic compounds and can be used in daily necessities, light chemical industry, textile, papermaking, printing and dyeing and other industrial applications.

[0042] The beneficial effects that can be achieved by the present application will be further illustrated below in combination with embodiments and comparative examples.

[0043] Example 1

[0044] The first raw material is 105# oxidized Fischer-Tropsch wax, which has an acid value of 28 mgKOH / g, a saponification value of 70 mgKOH / g, and a drop melting point of 105°C. Figure 1 The process shown is to prepare amide wax, which is as follows:

[0045] 25g of oxidized Fischer-Tropsch wax is added to the amination reactor, and the air in the reactor is replaced with nitrogen. After the replacement is qualified, that is, the oxygen content is <0.5% (the same below), 100mL of dimethylbenzene with water is added to the reactor under nitrogen protection, and the first raw material is melted by heating, and the water-carrying agent is continued to be heated until the water-carrying agent boils, and the water-carrying agent steam continues to flow back to the reaction liquid after condensation and water separation by the water separator. The water-carrying agent boils, and the temperature of the reaction liquid is 140°C at this time. 1.25g of propylene diamine with a temperature of 100°C after heating is added dropwise to the reaction liquid, and the dropping time is controlled to be 20min, and the material is continued to boil, and the temperature is 140°C, and the reaction is 2.5h. During the reaction, the generated water is taken out by the water-carrying agent to promote the formation of amide wax. After the reaction is completed, the water-carrying agent is evaporated, and the prepared amide wax product is subjected to performance testing and packaged.

[0046] Example 2

[0047] The difference from Example 1 is that the first raw material is 80# oxidized Fischer-Tropsch wax, which has an acid value of 28 mgKOH / g, a saponification value of 70 mgKOH / g, and a drop melting point of 82°C.

[0048] Example 3

[0049] The difference from Example 1 is that the second raw material is 2.5 g of hexamethylenediamine.

[0050] Example 4

[0051] The difference from Example 1 is that the second raw material is 0.25 g of propylenediamine.

[0052] Example 5

[0053] The difference from Example 1 is that the second raw material is 0.75 g of propylenediamine.

[0054] Example 6

[0055] The difference from Example 1 is that the second raw material is 1.25 g of diethanolamine.

[0056] Example 7

[0057] The difference from Example 1 is that the second raw material is 1.25 g of butanediamine.

[0058] Example 8

[0059] The difference from Example 1 is that the water-carrying agent is toluene of the same weight, and the temperature of the reaction liquid before and after the addition of propylene diamine is 110° C. respectively.

[0060] Example 9

[0061] The difference from Example 1 is that the reaction is continued for 0.5 h after the second raw material is added dropwise.

[0062] Example 10

[0063] The difference from Example 1 is that after the second raw material is added dropwise, the reaction is continued for 5 hours.

[0064] Embodiment 11

[0065] The difference from Example 1 is that the dropwise addition time of the second raw material is 40 min.

[0066] Example 12

[0067] The difference from Example 1 is that propylenediamine at room temperature (25° C.) is added dropwise into the reaction kettle.

[0068] Comparative Example 1

[0069] The difference from Example 1 is that the first raw material is the same weight of Tianjin Komiou analytically pure stearic acid.

[0070] Comparative Example 2

[0071] The first raw material used is the same as that in Example 1, and no water-carrying agent is added. 25g of oxidized Fischer-Tropsch wax is added to the amination reactor, and the air in the reactor is replaced with nitrogen. After the replacement is qualified, the first raw material is heated to melt. At this time, the temperature of the reaction liquid is 100°C, and propylene diamine with a temperature of 100°C after heating is added dropwise to the reaction liquid. The dropping time is controlled to be 0.5h, and the reaction temperature is continued to be maintained at 140°C for 2.5h. After the reaction is completed, the prepared amide wax product is subjected to performance testing.

[0072] Comparative Example 3

[0073] The difference from Example 1 is that after the water-carrying agent boils, the temperature of the reaction liquid is 140°C, 1.25 g of propylenediamine heated to 100°C is added to the reaction liquid at one time, and the subsequent treatment conditions are the same as those in Example 1.

[0074] The performance indexes of the amide wax prepared in the above examples and comparative examples are shown in Table 1 below.

[0075] Table 1

[0076]

[0077] From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: the preparation method uses oxidized Fischer-Tropsch wax as raw material, introduces a more polar amide group into the Fischer-Tropsch wax, and the product has a low acid value and a high amine value, so that it has a higher polarity, better emulsification, pigment dispersibility and oil retention. On the other hand, the amide wax prepared by this method overcomes the problems of lower drop melting point, reduced hardness and easy precipitation in high temperature weather after oxidation of Fischer-Tropsch wax, which can meet the different needs of downstream products and improve the economic added value of Fischer-Tropsch wax production.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing amide wax, characterized in that, include: Oxidized Fischer-Tropsch wax is placed in a reaction device as the first raw material, a water-carrying agent is added and mixed with the first raw material in an inert atmosphere, the first raw material is heated until it is melted and the water-carrying agent is boiling and refluxed, the second raw material is added dropwise, and the reaction is continued for 1 to 10 hours after the addition is completed, the reaction temperature is 110 to 150° C., the water-carrying agent is separated, and an amide wax product is obtained; The second raw material is selected from any one or more of diamine and alcoholamine compounds; The acid value of the oxidized Fischer-Tropsch wax is 15-30 mgKOH / g, the saponification value of the oxidized Fischer-Tropsch wax is 35-110 mgKOH / g, and the drop melting point of the oxidized Fischer-Tropsch wax is 80-110°C.

2. The preparation method according to claim 1, characterized in that: The diamine is selected from any one or more of diethylenetriamine, ethylenediamine, propylenediamine, butylenediamine, pentanediamine, hexamethylenediamine, heptanediamine, dodecanediamine and p-phenylenediamine.

3. The preparation method according to claim 2, characterized in that: The alcoholamine compound is selected from any one or more of monoethanolamine, diethanolamine and triethanolamine.

4. The preparation method according to claim 1, characterized in that: The amount of the second raw material is 1% to 10% by weight of the oxidized Fischer-Tropsch wax.

5. The preparation method according to claim 4, characterized in that: The amount of the second raw material used is 3% to 6% by weight of the oxidized Fischer-Tropsch wax.

6. The preparation method according to claim 4, characterized in that: The second raw material is preheated before being added dropwise.

7. The preparation method according to claim 6, characterized in that: The dropwise addition time of the second raw material is 15 min to 40 min.

8. The preparation method according to claim 4, characterized in that: The inert atmosphere is selected from any one or more of nitrogen and argon.

9. The preparation method according to claim 1, characterized in that: When the second raw material is added dropwise, the temperature of the reaction liquid is 110 to 150°C.

10. The preparation method according to claim 1, characterized in that: After the dropwise addition is completed, the reaction is continued for 1 to 3 hours.

11. The preparation method according to claim 1, characterized in that: The water-carrying agent is any one or more of toluene, xylene, trimethylbenzene, n-octane and n-heptane.

12. The preparation method according to any one of claims 1 to 11, characterized in that: The preparation method further comprises that after the water-carrying agent is heated to a boiling state, the steam of the water-carrying agent is condensed and separated by a water separator before returning to the reaction liquid.

13. The preparation method according to claim 12, characterized in that: The amount of the water-carrying agent used is 2 to 10 times the weight of the oxidized Fischer-Tropsch wax.

14. The preparation method according to claim 13, characterized in that: The amount of the water-carrying agent used is 3 to 5 times the weight of the oxidized Fischer-Tropsch wax.

15. An amide wax, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 14.

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