Preparation method for synthesizing fatty acid by oxidizing higher alcohol

Abstract

The invention provides a preparation method for synthesizing fatty acid by oxidizing higher alcohol, which is mainly technically characterized in that the higher alcohol is RCH2OH (C12-C18, octadecanol, hexadecanol and dodecanol), 4 tons of higher alcohol is used in each tower, pure oxygen is used, and the flow rate is 0.04 m / (h.kg); the catalyst is Pd / C nano powder (such as 5% Pd / C, and the dosage is 20kg / 4 tons of higher alcohol). The reaction general formula is RCH2OH + O2-RCOOH (synthetic fatty acid). The method has the advantage that the yield of pure oxygen supply is higher than that of air direct oxygen supply. The oxygen concentration is improved, air recycling is achieved, and the rate and efficiency of the oxidation reaction are directly determined through oxygen concentration adjustment and temperature control. And the method can be widely applied to the fields of industry, food and feed, medicine and cosmetics, new energy, environmental protection and the like.

Description

Technical Field

[0001] This invention relates to a method for preparing fatty acids by oxidizing higher alcohols (C12-C18), belonging to the field of organic synthesis technology. Specifically, it relates to a method for preparing fatty acids by oxidizing higher alcohols. Background Technology

[0002] Synthetic fatty acids are widely used in industrial fields such as surfactants, lubricants and metalworking fluids, and plastics and rubber additives. They are also used in many other industries, including food and feed, pharmaceuticals and cosmetics, new energy and environmental protection. However, current synthetic fatty acid production often falls short of market demand due to limitations in equipment and molding processes. Furthermore, the exhaust gas generated during synthesis is often incompletely combusted and consumes excessive energy, issues that urgently need to be addressed.

[0003] Currently, there are four main methods for synthesizing fatty acids from higher alcohols: direct oxidation with strong oxidants, two-stage oxidation, catalytic oxidation (green chemistry method), and biocatalytic oxidation. Some of these methods produce many byproducts and cause serious pollution, while others have high production costs and are only suitable for laboratories, which do not match market demand.

[0004] Current synthetic fatty acid technologies produce large volumes of exhaust gases, and the corresponding exhaust gas treatment technologies fail to meet emission standards (due to incomplete combustion and high energy consumption); moreover, energy and raw material consumption are expensive. Insufficient production makes it difficult to meet market demand, resulting in numerous byproducts, severe pollution, or high production costs and energy and raw material consumption.

[0005] Therefore, increasing production and achieving high-efficiency, low-energy-consumption chemical synthesis have become common goals in recent years. This is a pressing issue that needs to be addressed. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for preparing fatty acids through the oxidation of higher alcohols.

[0007] This invention not only increases output and achieves the goal of high efficiency and low energy consumption, but also ensures that the exhaust gas treatment technology meets the standards.

[0008] The objective of this invention is achieved through the following technical solution: It includes the following raw material components: RCH2OH (C12-C18 higher alcohols); the raw materials for this preparation method are composed of the following parts by weight: Its characteristic is that... Higher alcohols: RCH2OH (C12-C18, octadecyl alcohol, hexadecyl alcohol, dodecanol), the quantity per tower is determined according to requirements. This invention proposes 3-5 tons as an example, the oxygen flow rate corresponding to each ton is different, and the amount of catalyst also varies.

[0009] Each tower contains 3 tons of oxygen, with a pure oxygen flow rate of 0.03 m³ / (h·kg). Each tower holds 4 tons of oxygen, with a pure oxygen flow rate of 0.04 m³ / (h·kg). Each tower holds 5 tons of oxygen, with a pure oxygen flow rate of 0.05 m³ / (h·kg). Catalyst: Pd / C nanoparticles, 5% Pd / C, dosage 15 kg / 3 tons of higher alcohols Catalyst: Pd / C nanoparticles, 5% Pd / C, dosage 20 kg / 4 tons of higher alcohols Catalyst: Pd / C nanoparticles, 5% Pd / C, dosage 25 kg / 5 tons of higher alcohols General reaction formula: RCH2OH + O2 → RCOOH (synthesis of fatty acids) The specific preparation process steps of this invention are characterized by: The process steps of this invention are as follows: 1. Batching and feeding: Batching, feeding, heating, starting the blower, starting the pump, adding the catalyst, adjusting the oxygen concentration, and supplying oxygen are performed sequentially, following the normal oxidation steps. Taking the oxidation synthesis of fatty acids from C18 higher alcohols as an example: Specifically, step 1: Octadecyl alcohol is stored in a storage tank at the factory, and all physicochemical properties are checked. During production, 4 tons of octadecyl alcohol are heated to 90°C and fed into the oxidation tower, and the temperature is raised to 100°C. 2. Start the pipeline fan and high-pressure jet pump. Start the high-pressure jet pump to circulate and stir the material. Then add 20 kg of 5% Pd / C nanoparticle powder. Utilize the pump's acceleration, diversion, and jetting capabilities to ensure full contact between the material and the catalyst. Simultaneously, start the oxygen generator to continuously supply oxygen to the tower for the oxidation reaction. This reaction is achieved through: the high-pressure jet pump delivers high-pressure material, spraying a high-speed liquid stream from each linear nozzle. Upon impact with the material surface, numerous vortices are generated, causing the high-oxygen-content gas within the tower to be trapped deep within the material, forming bubbles of varying diameters. These bubbles are in full contact with the material. With continuous circulation, bubbles are constantly being generated and defoamed. Because smaller bubbles defoam more slowly, there is sufficient oxygen inside the material during normal reaction. Under the influence of temperature and the catalyst, oxygen interacts with the hydroxyl groups of alcohols to generate fatty acids. The key to this reaction is controlling the oxygen concentration and temperature to avoid excessive oxidation of aldehydes. It does not rely on an initiation reaction. This reaction is irreversible, with good directionality in fatty acid formation and a relatively fast reaction rate. 3. Reaction Control: During normal reaction, due to the rapid oxygen consumption, the oxygen concentration in the conveying tower is maintained at approximately 35% of the mixed air using an online oxygen content detector. Temperature Control: As this reaction is exothermic, to maintain the reaction temperature at 100℃, heating coils and circulating cooling water coils are installed in the tower. Heating is activated when the material temperature is below 100℃, and cooling is activated when the temperature is above 100℃. After the oxygen generator starts supplying oxygen, the cooling water pump is turned on, and the circulating water volume is controlled by a valve backflow to maintain the reaction temperature at 100℃. During oxidation, the gas in the tower is guided by a pipe fan to the condenser for condensation and separation. The inlet temperature of the first condenser is 80℃, and the outlet temperature is 50℃. The inlet temperature of the second condenser is 50℃, and the outlet temperature is 25℃. At this temperature, most of the organic matter in the condensed liquid is separated and enters the storage tank. After sedimentation, oil-soluble acids and water-soluble acids are separated. 4. Tail Gas Treatment: Uncondensed gas is returned to the tower by a pipe fan to continue participating in oxidation, achieving zero emissions. During the production process, trace amounts of gaseous organic matter were not condensed and absorbed, and therefore were not discharged. Operational results show that the exhaust gas, under the above conditions, has completely achieved the purification objective. 5. Final Results: During normal oxidation, the acid value was measured every hour. When the acid value reached 120 mg KOH / g, it was measured every 30 minutes. The standard acid value is no less than 160 mg KOH / g. Once the required acid value is met, oxygen supply was stopped, the circulating pump was shut off, and the production line was purged with high-pressure steam. Then, the feed pump pumped the oxidation product into the storage tank. The product was separated and purified to obtain fatty acids.

[0010] Reaction Mechanism: Higher alcohols initiate a continuous reaction of their oxides under the influence of catalysts, heat, and bubbles generated by high-pressure liquid pressure. General Reaction Formula: RCH2OH + O2 → RCOOH (Fatty Acids). In the process of oxidizing higher alcohols to synthesize fatty acids, air with a higher oxygen concentration is used instead of pure air, reducing the air content in the exhaust gas, and this portion of air can be recycled. Most of the oxygen reacts with the higher alcohols to produce synthetic fatty acids and water. The water evaporates rapidly at a high temperature (100℃) and under the action of wind-driven stirring, and is then condensed and separated in a condenser.

[0011] Experimental data on the normal oxidation of fatty acids through the oxidation of octadecanol: After the first hour, the acid value was 36 mg KOH / g.

[0012] After 2 hours, the acid value was 80 mg KOH / g.

[0013] After 3 hours, the acid value was 122 mg KOH / g.

[0014] After 3.5 hours, the acid value was 144 mg KOH / g.

[0015] After 4 hours, the acid value was 165 mg KOH / g.

[0016] Product parameters: 1. The synthetic fatty acid obtained by this invention has an acid value of not less than 160 mgKOH / g, a saponification value of 190 mgKOH / g, and the content of unsaponifiables in the sodium salt of the synthetic fatty acid separated by saponification is less than 10%.

[0017] 2. Using this process to treat the tail gas of high-grade alcohol oxidation, based on an annual synthetic fatty acid production of 5,000 tons, the fuel cost can be reduced by 750,000 yuan per year compared to the traditional process's tail gas fuel cost of 150 yuan per ton, essentially achieving zero emissions.

[0018] High efficiency: Optimized oxygen concentration (35%) and temperature (100℃) result in a uniform and controllable reaction rate and stable conversion rate.

[0019] Low energy consumption and environmental protection: High oxygen content air is recycled, reducing exhaust emissions and treatment costs, and achieving zero atmospheric emissions.

[0020] High yield: A high-pressure jet pump enhances gas-liquid contact, resulting in a faster oxidation rate for short carbon chains (C12) compared to long carbon chains (C18), achieving a yield of 80%-82.5% (compared to only 57.5%-65% using traditional methods). In the oxidation of higher alcohols to fatty acids, oxygen concentration is a key influencing factor: excessively high concentrations lead to uncontrollable and rapid oxidation reactions, resulting in complex and poorly oriented products that fail to achieve the expected conversion rate; excessively low concentrations reduce production efficiency. This invention optimizes the oxygen concentration to ensure a suitable, uniform, and controllable oxidation reaction rate, guaranteeing a suitable carbon chain structure in the obtained fatty acids and a stable and controllable reaction conversion rate.

[0021] 1. Compared with existing technologies, the innovation of this invention is to increase the oxygen concentration and realize air recycling. The stability of the oxygen concentration and temperature control in the tower are the key to the smooth production of fatty acids in the higher alcohol oxidation reaction. 2. The recycling of high oxygen content air is another innovation of this invention, in which the adjustment of oxygen concentration and temperature control directly determine the rate and efficiency of oxidation reaction. Attached Figure Description

[0022] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and prior art: Prior art analysis 1: The synthesis of fatty acids from octadecyl alcohol oxidation differs from embodiment 1 in the method of providing oxygen. A fan is used to deliver mixed air at an input rate of 0.06 m³ / h·kg. After heating to 100°C, air supply, and catalyst addition, normal oxidation occurs. Experimental production analysis data: Hour 1, acid value 12 mgKOH / g; Hour 3, acid value 30 mgKOH / g; Hour 5, acid value 60 mgKOH / g; Hour 7, acid value 93 mgKOH / g; Hour 9, acid value 120 mgKOH / g; Hour 11, acid value 145 mgKOH / g; Hour 11.5, acid value 153 mgKOH / g; Hour 12, acid value 161 mgKOH / g. The acid value, measured to be 161 mg KOH / g, met the standard acid value before exiting the tower. After separation and purification, the fatty acid conversion was 2.40 tons, with a yield of 60%, and the reaction time was 12 hours.

[0024] Embodiment 1 of the present invention Preparation of fatty acids by octadecyl alcohol oxidation: Higher alcohols are oxidized through a series of steps including batching, feeding, heating, starting the blower, starting the circulating pump, adding the catalyst, and oxygen supply to produce synthetic fatty acids. In the batching step, the raw materials are mixed according to the following weight proportions: 4 tons of higher alcohols per tower, with a pure oxygen flow rate of 0.04 m³ / (h·kg), and the oxygen concentration inside the tower is controlled at 35% of the mixed air. After heating to 100℃, the pipeline blower and high-pressure jet pump are started, the catalyst is added, and the oxygen generator is started to supply oxygen and adjust the oxygen concentration. The product is discharged from the tower after the acid value reaches the qualified standard (measured acid value 165 mgKOH / g). After separation and purification, the fatty acid conversion yield is 3.20 tons, with a yield of 80%, and the reaction time is 4 hours.

[0025] Octadecyl alcohol was oxidized to synthesize fatty acids (the difference from Example 1 lies in the oxygen supply method): a blower was used to supply mixed air at an input rate of 0.06 m³ / (h·kg). After heating to 100°C, air was supplied, a catalyst was added, and normal oxidation was carried out. The experimental production analysis data are as follows: 1 hour, acid value 12 mgKOH / g; 3 hours, acid value 30 mgKOH / g; 5 hours, acid value 60 mgKOH / g; 7 hours, acid value 93 mgKOH / g; 9 hours, acid value 120 mgKOH / g; 11 hours, acid value 145 mgKOH / g; 11.5 hours, acid value 153 mgKOH / g; 12 hours, acid value 161 mgKOH / g. At 12 hours, the acid value reached 161 mgKOH / g, but the content of by-products increased, and the color deepened significantly. After separation and purification, the fatty acid conversion was 2.30 tons, with a yield of 57.5%, and the reaction time was extended to 12 hours. Compared with Example 1, under the same catalyst dosage, the oxygen supply using air was less efficient, resulting in incomplete oxidation, a longer reaction cycle, and a lower yield. This demonstrates that increasing the oxygen concentration and implementing a circulating oxygen supply plays a decisive role in the reaction rate and product yield. As stated in *Tiangong Kaiwu* (The Exploitation of the Works of Nature), "Gunpowder is mainly composed of saltpeter; abundant oxygen makes it powerful." Similarly, in oxidation reactions, "abundant oxygen," meaning high oxygen partial pressure and continuous oxygen supply, leads to a more complete reaction. Compared with the prior art analysis 1, Example 1 of this invention shortened the acid value attainment time by over 70% and significantly reduced energy consumption, verifying that an oxygen-rich environment can accelerate the reaction process and promote the efficient conversion of alcohols to acids.

[0026] Meanwhile, in Example 2, the catalyst ratio was optimized based on Example 1, using a composite catalyst (cobalt salt to manganese salt molar ratio of 3:1). The reaction was carried out under the same process conditions. The acid value reached 18 mgKOH / g in the first hour, and after 2.5 hours, the acid value reached the standard and was discharged from the tower, with a measured acid value of 161 mgKOH / g. After separation and purification, the fatty acid conversion was 2.40 tons, with a yield of 60%, and the reaction time was 12 hours.

[0027] Existing technology analysis 2: Cetyl alcohol oxidation to fatty acid synthesis (the difference from Example 2 lies in the oxygen supply method): A fan is used to deliver mixed air at an input rate of 0.06 m³ / (h·kg). After heating to 100°C, air is supplied, a catalyst is added, and normal oxidation is carried out. Experimental production analysis data are as follows: The acid value was 14 mgKOH / g in the first hour; 41 mgKOH / g in the third hour; 69 mgKOH / g in the fifth hour; 101 mgKOH / g in the seventh hour; 132 mgKOH / g in the ninth hour; 162 mgKOH / g in the eleventh hour; 174 mgKOH / g in the eleventh and 12th hours; and 183 mgKOH / g in the twelfth hour. After reaching the standard acid value, the product was discharged from the tower, with an actual measured acid value of 183 mgKOH / g. After separation and purification, the fatty acid conversion was 2.5 tons, with a yield of 62.5%, and the reaction time was 12 hours.

[0028] Embodiment 2 of the present invention Preparation of fatty acids by cetyl alcohol oxidation: Higher alcohols are oxidized through a series of steps including batching, feeding, heating, starting the blower, starting the circulating pump, adding the catalyst, and oxygen supply for oxidation to obtain synthetic fatty acids. The batching process involves mixing the raw materials according to the following weight proportions: 4 tons of higher alcohols per tower, with a pure oxygen flow rate of 0.04 m³ / (h·kg), and the oxygen concentration inside the tower is controlled at 35% of the mixed air. After heating to 100℃, the pipeline blower and high-pressure jet pump are started, the catalyst is added, and the oxygen generator is started to supply oxygen and adjust the oxygen concentration. The acid value standard is not less than 180 mgKOH / g.

[0029] After the first hour of experimental production analysis, the acid value was 40 mg KOH / g. After the second hour, the acid value was 84 mg KOH / g. After the third hour, the acid value was 135 mg KOH / g. After 3.5 hours, the acid value was 161 mg KOH / g. After the fourth hour, the acid value was 182 mg KOH / g. After the acid value reached the standard, the product was discharged from the tower, and the actual measured acid value was 182 mg KOH / g. After separation and purification, the fatty acid conversion was 3.26 tons, the yield was 81.5%, and the reaction time was 4 hours.

[0030] Existing technology analysis 3 The oxidation of dodecanol to synthesize fatty acids (the difference from Example 3 lies in the oxygen supply method): A blower was used to supply mixed air at an input rate of 0.06 m³ / (h·kg). After heating to 100°C, air was supplied, a catalyst was added, and normal oxidation was carried out. Experimental production analysis data are as follows: Hour 1, acid value 20 mgKOH / g; Hour 3, acid value 63 mgKOH / g; Hour 5, acid value 105 mgKOH / g; Hour 7, acid value 150 mgKOH / g; Hour 9, acid value 188 mgKOH / g; Hour 11, acid value 216 mgKOH / g; Hour 11.5, acid value 224 mgKOH / g; Hour 12, acid value 235 mgKOH / g. After the acid value reached the standard, the product was discharged from the tower, with a measured acid value of 235 mgKOH / g. After separation and purification, the fatty acid conversion was 2.6 tons, the yield was 65%, and the reaction time was 12 hours.

[0031] Embodiment 3 of the present invention Preparation of fatty acids by dodecanol oxidation: Higher alcohols are oxidized through a process involving batching, feeding, heating, starting the blower, starting the circulating pump, adding the catalyst, and oxygen supply to produce synthetic fatty acids. The batching process involves mixing the raw materials according to the following weight proportions: 4 tons of higher alcohols per tower, with a pure oxygen flow rate of 0.04 m³ / (h·kg), and the oxygen concentration inside the tower controlled at 35% of the mixed air. After heating to 100℃, the pipeline blower and high-pressure jet pump are started, the catalyst is added, and the oxygen generator is started to supply oxygen and adjust the oxygen concentration, ensuring the acid value standard is not less than 230 mgKOH / g.

[0032] After the first hour of experimental production analysis, the acid value was 46 mgKOH / g; after the second hour, it was 105 mgKOH / g; after the third hour, it was 165 mgKOH / g; after 3.5 hours, it was 201 mgKOH / g; and after the fourth hour, it was 234 mgKOH / g. The product was discharged from the tower after meeting the standard acid value, and the actual measured acid value was 234 mgKOH / g. After separation and purification, the fatty acid conversion was 3.3 tons, with a yield of 82.5%, and the reaction time was 4 hours.

[0033] A comparative analysis of the present invention and existing technologies reveals significant differences in equipment and process conditions, leading to markedly different reaction results. Examples 1-3 utilize pure oxygen supply and controlled oxygen concentration, combined with a high-pressure jet pump for material circulation. Multiple linear nozzles introduce a high-oxygen-concentration mixed gas from the material surface into the interior, forming microbubbles to ensure sufficient contact between oxygen and the material, thus accelerating the reaction. In contrast, existing technologies 1-3 use fans to deliver air, resulting in insufficient contact between the material and oxygen, a slower reaction rate, a large volume of uncondensed mixed gas, and high and difficult-to-meet exhaust gas treatment costs. The reaction rate of higher alcohol oxidation to fatty acids is influenced by multiple factors, including carbon chain length, catalyst performance, and reaction mechanism. Short-chain higher alcohols typically oxidize faster than long-chain higher alcohols because their oxidation requires multiple steps: dehydrogenation → oxidation → deep oxidation. Short-chain intermediates are more stable, facilitating reaction progression. Long-chain alcohols exhibit increased hydrophobicity and viscosity with increasing carbon chain length, reducing their diffusion rate in the reaction medium and their contact efficiency with the catalyst. The present invention, by introducing a high-pressure jet pump, effectively improves the diffusion rate of long-chain alcohols and the catalyst contact efficiency, thereby increasing the reaction conversion rate. In the future, we can further explore methods to reduce the viscosity of long-chain higher alcohols, improve equipment structure, or develop new high-efficiency catalyst combinations to continuously optimize the oxidation reaction rate.

[0034] The following is a detailed analysis and comparison of these two oxygen supply methods: I. Oxygen Supply Method Pure oxygen concentration controlled (35%) + high-pressure jet pump circulation: Pure oxygen supply: Providing relatively pure oxygen helps ensure the smooth progress of chemical reactions.

[0035] Concentration control: The oxygen concentration is controlled at 35% to meet the specific requirements of the chemical reaction.

[0036] High-pressure jet pump circulation: Oxygen can be recycled using a high-pressure jet pump, which helps to save resources and improve efficiency.

[0037] Direct oxygen supply from air (fan delivery): Oxygen source: Oxygen is extracted directly from the air to meet the reaction requirements.

[0038] Fan delivery: Air is drawn in and delivered to the reaction area by a fan. This method is relatively low cost.

[0039] II. Reaction Time The data shows that for C12, C16, and C18 alcohols, the reaction time using a pure oxygen concentration control method combined with a high-pressure jet pump circulation is significantly faster than that using direct air oxygen supply. This is because the pure oxygen supply is more abundant, accelerating the chemical reaction.

[0040] III. Yield In terms of yield, the oxygen supply method using controlled concentration of pure oxygen plus a high-pressure jet pump circulation was significantly higher than that using direct air supply. For C18 alcohols, the former achieved a yield of 80%, while the latter only reached 57.5%. For C16 and C12 alcohols, although the yields differed between the two oxygen supply methods, the yield from pure oxygen supply was still higher than that from direct air supply. This indicates that under the same conditions, using pure oxygen supply can more effectively facilitate chemical reactions and yield higher product yields.

[0041] In conclusion, considering both reaction time and yield, the oxygen supply method of controlling the concentration of pure oxygen and circulating it with a high-pressure jet pump is significantly superior to the method of directly supplying oxygen with air.

[0042] Product Applications: Synthetic fatty acids are widely used in many fields such as industry, food and feed, medicine and cosmetics, new energy and environmental protection.

[0043] The mechanism of this invention is that "higher alcohols" is a general term for a class of alcohol compounds. The core is long-chain fatty alcohols containing 6 or more carbon atoms, not "alcohols containing a certain proportion" - as long as the molecular structure conforms to "long-chain alkyl + hydroxyl (-OH)", it belongs to higher alcohols.

[0044] Common examples include hexanol (6 carbons), octanol (8 carbons), and dodecanol (12 carbons), each molecule of which contains only one hydroxyl group (the characteristic functional group of alcohols). Let's break down the functions of three typical compounds containing RCH2- for easier understanding: 1. Ethanol (R=H, i.e., HCH2OH, which can also be written as CH3CH2OH) Here, RCH2- stands for ethyl (CH3CH2-), which provides a hydrophobic carbon chain. It weakens the interaction between the molecule and water molecules, allowing ethanol to dissolve in both water (due to the hydroxyl group -OH) and oils (due to the ethyl group). This is the key to ethanol's ability to act as a solvent and disinfectant—its dual hydrophilic and lipophilic properties allow it to penetrate cells and destroy proteins.

[0045] 2. Bromoethane (R=H, CH3CH2Br) RCH2-, also an ethyl group, plays a crucial role as a "carbon skeleton support," carrying the reactive bromine atom (-Br). Due to the strong electronegativity of the bromine atom, the ethyl group exhibits a certain degree of positive charge, making the entire molecule prone to substitution reactions (such as reacting with OH⁻ to produce ethanol). It is a commonly used raw material in organic synthesis for "introducing ethyl groups into molecules."

[0046] 3. Ethyl acetate (R=CH3CO-, i.e., CH3COOCH2CH3) Here, RCH2- represents the ethyl group in ethoxylate (CH3CH2- in CH3CH2O-), and its function is to regulate molecular polarity and volatility. The hydrophobicity of the ethyl group makes ethyl acetate less polar, more volatile, and insoluble in water. Therefore, it is often used as a solvent for paints and food flavorings (such as pineapple flavor) – volatility brings fragrance, and low polarity can dissolve oily resins.

Claims

1. A method for preparing fatty acids by oxidation of higher alcohols, comprising the following raw material components: RCH2OH (C12-C18 higher alcohols); the raw materials for this preparation method are produced in the following weight proportions: characterized in that... Synthetic fatty acids were produced by mixing higher alcohols through processes including batching, feeding, heating, starting the blower, starting the circulating pump, adding the catalyst, and oxygen oxidation. The batching process involved mixing the raw materials in the following weight proportions: 4 tons of higher alcohols per tower, a pure oxygen flow rate of 0.04 m³ / (h·kg), and the oxygen concentration in the tower was controlled at 35% of the mixed air. After heating to 100℃, the pipeline blower and high-pressure jet pump were started, the catalyst was added, and the oxygen generator was started to supply oxygen and adjust the oxygen concentration. After the acid value reached the qualified standard, the product was discharged from the tower. The measured acid value was 165 mgKOH / g. After separation and purification, the fatty acid conversion was 3.20 tons, with a yield of 80%, and the reaction time was 4 hours.

2. The method for preparing fatty acids by oxidation of higher alcohols according to claim 2, characterized in that, higher... Alcohol: RCH2OH (C12-C18, octadecyl alcohol, hexadecyl alcohol, dodecanol), the quantity per tower is determined according to the needs. This invention proposes 3-5 tons as an example. The oxygen flow rate corresponding to each ton is different, and the amount of catalyst also varies. Each tower contains 3 tons of oxygen, with a pure oxygen flow rate of 0.03 m³ / (h·kg). Each tower holds 4 tons of oxygen, with a pure oxygen flow rate of 0.04 m³ / (h·kg). Each tower holds 5 tons of oxygen, with a pure oxygen flow rate of 0.05 m³ / (h·kg). Catalyst: Pd / C nanoparticles, 5% Pd / C, dosage 15 kg / 3 tons of higher alcohols Catalyst: Pd / C nanoparticles, 5% Pd / C, dosage 20 kg / 4 tons of higher alcohols Catalyst: Pd / C nanoparticles, 5% Pd / C, dosage 25 kg / 5 tons of higher alcohols The general reaction formula is: RCH2OH + O2 → RCOOH (synthesis of fatty acids).

3. The method for preparing fatty acids by oxidation of higher alcohols according to claim 1, characterized in that, Preparation of fatty acids by cetyl alcohol oxidation: Higher alcohols are oxidized through a series of steps including batching, feeding, heating, starting the blower, starting the circulating pump, adding the catalyst, and oxygen supply to produce synthetic fatty acids. The batching process involves mixing the raw materials in the following weight proportions: 4 tons of higher alcohols per tower, a pure oxygen flow rate of 0.04 m³ / (h·kg), and the oxygen concentration inside the tower controlled at 35% of the mixed air. After heating to 100℃, the pipeline blower and high-pressure jet pump are started, the catalyst is added, and the oxygen generator is started to supply oxygen and adjust the oxygen concentration. The acid value standard is not less than 180 mgKOH / g. After separation and purification, the fatty acid conversion yield is 3.26 tons, with a yield of 81.5%, and the reaction time is 4 h.

4. The method for preparing fatty acids by oxidation of higher alcohols according to claim 1, characterized in that, dodecyl... Preparation of fatty acids by alcohol oxidation: Higher alcohols are oxidized through a series of steps including batching, feeding, heating, starting the blower, starting the circulating pump, adding the catalyst, and oxygen supply for oxidation to obtain synthetic fatty acids. The batching process involves mixing raw materials in the following weight proportions: 4 tons of higher alcohols per tower, with a pure oxygen flow rate of 0.04 m³ / (h·kg), and the oxygen concentration inside the tower controlled at 35% of the mixed air. After heating to 100℃, the pipeline blower and high-pressure jet pump are started, the catalyst is added, and the oxygen generator is started to supply oxygen and adjust the oxygen concentration. The acid value standard is not less than 230 mgKOH / g. After separation and purification, the fatty acid conversion yield is 3.3 tons, with a yield of 82.5%, and the reaction time is 4 hours.

5. The method for preparing fatty acids by oxidation of higher alcohols according to claim 1, characterized in that, Pure oxygen is used for air supply and the oxygen concentration is controlled. Combined with a high-pressure jet pump, material circulation is achieved. High-oxygen-concentration mixed gas is introduced from the surface of the material into the interior through multiple linear nozzles to form microbubbles, ensuring that oxygen and material are in full contact, thereby accelerating the reaction. The oxidation rate of short-chain higher alcohols is faster than that of long-chain higher alcohols because their oxidation requires a process of dehydrogenation → oxidation → deep oxidation. Short-chain intermediates are more stable, which is conducive to the advancement of the reaction.

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