Method for preparing C8 aliphatic amine by taking C8 fatty alcohol as raw material and supported metal catalyst used in method

Abstract

The invention belongs to the field of chemical engineering, and particularly discloses a supported metal catalyst for preparing C8 aliphatic amine, the supported metal catalyst is composed of an active component and a catalyst carrier; the active component is composed of 0-30% of cobalt, 0-5% of copper, 0-4% of magnesium and 0-3% of zinc based on the weight of the supported metal catalyst; and the balance is a catalyst carrier. The invention also provides a method for preparing C8 fatty amine by taking C8 fatty alcohol as a raw material, and the supported metal catalyst is utilized. The supported metal catalyst provided by the invention is suitable for the production of three types of C8 fatty amines, namely n-octylamine prepared from n-octanol, isooctylamine prepared from isooctanol and sec-octylamine prepared from sec-octanol, and has the advantages of high conversion rate, high catalyst activity and long service life.

Description

Technical Field

[0001] The present invention belongs to the chemical industry field, and particularly relates to a production method for preparing C8 fatty amine from C8 fatty alcohol and a related catalyst. Background Art

[0002] The alkyl carbon atoms of C8 fatty amine are 8, mainly including n-octylamine, isooctylamine and sec-octylamine series products. It is an important chemical raw material and is widely used in various fields such as medicine, agricultural chemicals, surfactants, softeners, extractants, dye pigments, antioxidants, preservatives, flotation agents, emulsifiers, rubber accelerators, etc.

[0003] The synthetic raw materials of fatty amines mainly include aldehydes and ketones, carboxylic acids, chloroalkanes, olefins, alcohols, nitriles, etc. In the existing industrial production technologies, most of them use catalytic ammoniation method with alcohol as raw material, and cobalt-based or copper-nickel-based catalysts are used.

[0004] n-Octylamine also includes the nitrilation-hydrogenation method with fatty acid as raw material, which has problems such as high energy consumption, strong corrosion, and high equipment requirements. "Research on the Process of Ammoniation of n-Octanoic Acid to Synthesize n-Octanenitrile" informs that n-octanoic acid reacts with ammonia at a temperature above 270 °C under the catalysis of a catalyst to obtain n-octanenitrile first, and then hydrogenation is carried out under the catalysis of a hydrogenation catalyst to generate n-octylamine.

[0005] In patent CN200610154969.X, using n-octanol and liquid ammonia as raw materials, a copper-nickel-based catalyst is used, and the reaction is carried out under liquid phase conditions in a high-pressure reaction kettle. The catalyst components are: 0.1% - 50% copper, 0.1% - 50% nickel, 0.005 - 0.1% ruthenium, 0.001% - 1.0 magnesium, and 0.01 - 5.0% chromium as additives. The reaction temperature is 190 - 300 °C, and the reaction pressure is 0.1 - 16.0 MPa. The intermittent reaction adopted has a long production cycle and low conversion rate.

[0006] The master's thesis "Research on the Catalytic Amination Reaction of n-Octanol" by Dalian Maritime University informs that: using 20% nickel and 2% copper as the main active components of the catalyst sample, 1% ruthenium and 0.5% zinc as the third and fourth additives, at a reaction temperature of 180 °C, a hydrogen pressure of 2 MPa, an ammonia-alcohol ratio of 10:1, and a space velocity of the raw material gas of 85.2 h -1 At this time, the raw material conversion rate of the catalytic amination reaction of n-octanol reached a maximum of 99.5%, and the product selectivity reached a best of 95%. However, ruthenium belongs to a noble metal catalyst and is expensive.

[0007] In the latest technical process, many patent articles use fixed beds for the production research of n-octylamine. Its continuous production method is good, but the reaction cycle and the catalyst usage cost are high, and the raw material conversion rate and product selectivity are not expected to be high.

[0008] Patent CN200310122670.2Z discloses a preparation method using isooctanol as a raw material. This method uses Cu-Co / Al2O3-diatomite as a catalyst. Under the conditions of 0.1-2.0 MPa and 150-280 °C, isooctanol reacts with ammonia and hydrogen in a fixed-bed reactor to produce isooctylamine, but the raw material conversion rate is only 70%, and the selectivity is 95%. The catalyst preparation method disclosed in this scheme involves the use of the expensive metal catalyst ruthenium.

[0009] Patent CN202111581873.2 discloses a synthesis method of isooctylamine and its derivatives by the one-pot method. The raw material n-butanal reacts with a basic skeletal nickel catalyst at normal pressure and ≤25 °C for 1 h, and then slowly heated to 35 °C and reacted for 0.5 h. In a cooling water environment, a condensation reaction occurs to obtain octenal; octenal is ammoniated and hydrogenated (3.0 MPa, 90-100 °C) to obtain the final product isooctylamine. The product is collected by distillation, and the yield is <90%.

[0010] Patent CN201010183266.6 discloses a preparation method of diisooctylamine. The raw materials isooctanol, ammonia, hydrogen, and catalyst carry out a catalytic ammoniation reaction in a high-pressure autoclave at 120-260 °C. The product selectivity is >90%, and the product purity is >99%.

[0011] The continuous production idea of C8 fatty amines is good. The catalytic ammoniation process has the characteristics of being green and environmentally friendly, with good atom economy. Theoretically, the by-product is water; especially, it does not rely on an external hydrogen source. Therefore, developing a process route with high conversion rate and high amine selectivity and a catalyst with high stability has extremely high industrial application value. Summary of the Invention

[0012] The technical problem to be solved by the present invention is to provide a method for preparing C8 fatty amines using C8 fatty alcohols as raw materials with high conversion rate and the supported metal catalyst used.

[0013] To solve the above technical problem, the present invention provides a supported metal catalyst for preparing C8 fatty amines. The supported metal catalyst is composed of an active component and a catalyst carrier; the active component is composed of 0-30% cobalt, 0-5% copper, 0-4% magnesium, and 0-3% zinc by weight of the supported metal catalyst; the catalyst carrier is the balance.

[0014] As an improvement of the supported metal catalyst of the present invention: the active component is composed of 15%-27.5% cobalt, 0.1%-2.5% copper, 0.5%-2.5% magnesium, and 0.1%-1.5% zinc by weight of the supported metal catalyst.

[0015] The present invention also simultaneously provides a preparation method of the above-mentioned supported metal catalyst for preparing C8 fatty amines, comprising the following steps:

[0016] ①. Mix pseudoboehmite, sesbania powder, deionized water, and nitric acid evenly, extrude into a shape, then dry and calcine to obtain a catalyst support;

[0017] The weight ratio of the pseudoboehmite: sesbania powder: deionized water: nitric acid is 100:(5±0.5):(150±20):(3±0.3);

[0018] ②. First, dissolve the nitrate corresponding to the active ingredient in water to obtain a mixed nitrate solution;

[0019] Then pour the mixed nitrate solution into the catalyst support obtained in step ① for impregnation - drying - calcination to obtain a supported catalyst precursor;

[0020] Note: The water absorption rate of the catalyst support can be measured in a conventional manner, and all the prepared mixed nitrate solution is absorbed by the catalyst support; in addition, due to calcination, metal oxides are attached to the supported catalyst;

[0021] ③. Carry out hydrogen reduction of the supported catalyst precursor obtained in step ② at high temperature to obtain a supported metal catalyst.

[0022] Note: The metal oxides are reduced by hydrogen at high temperature to form the corresponding metals; the hydrogen reduction involved in this step ③ can be carried out in a reactor for preparing C8 fatty amines.

[0023] As an improvement of the preparation method of the supported metal catalyst of the present invention, in step ①:

[0024] The drying is carried out at 120±20°C for 3±0.5 h;

[0025] The calcination is carried out as follows: first heat up to 300±30°C and calcine for 2±0.5 hours, then heat up to 550±50°C and calcine for 10±1 hour.

[0026] As a further improvement of the preparation method of the supported metal catalyst of the present invention, in step ②:

[0027] The number of times of impregnation - drying is 2 times (using two - time impregnation and two - time drying);

[0028] Each impregnation - drying is carried out as follows: first impregnate for 2±0.5 hours, then air - dry the impregnated catalyst support (air - dry until there is no obvious water stain on the surface) and then place it in an oven at 110±10°C to dry for 3±0.5 h;

[0029] The calcination is carried out at 650±25°C for 5±0.5 h.

[0030] As a further improvement to the preparation method of the supported metal catalyst of the present invention, in step ③, the hydrogen reduction at high temperature is as follows: reduction with hydrogen at a hydrogen pressure of 0.05 MPa and a temperature of 450 - 500 °C (preferably 480 °C) until no more water is produced.

[0031] For example, the space velocity is 1000 h -1 and reduce for 10 - 12 hours. The space velocity is the amount of hydrogen passing through the unit catalyst per unit time; continuously introduce hydrogen until the reduction is completed.

[0032] The present invention also simultaneously provides a method for preparing C8 fatty amines from C8 fatty alcohols. Using the above supported metal catalyst, it includes the following steps:

[0033] 1), Load the supported metal catalyst in the reactor;

[0034] 2), Mix C8 fatty alcohol with liquid ammonia and hydrogen through a metering pump, vaporize at 150 - 180 °C and then enter a fixed-bed reactor, and carry out catalytic ammoniation reaction under the action of the supported metal catalyst; wherein the molar ratio of ammonia: hydrogen: C8 fatty alcohol is 2 - 10:5:1; the reaction temperature is 150 - 200 °C (preferably 160 - 180 °C); the reaction pressure is 0.1 - 2.0 MPa (preferably 0.2 - 1.2 MPa), and the reaction space velocity (liquid space velocity) is 0.2 - 0.6 h -1 (preferably 0.3 - 0.5 h -1 );

[0035] Note: The reaction space velocity is the amount of alcohol passing through the unit catalyst per unit time, and the system pressure is adjusted and controlled by a back pressure valve on the vent pipeline;

[0036] 3), The material obtained from the ammoniation reaction in step 2) is condensed, cooled and separated into gas and liquid, forming a liquid-phase product and uncondensed gas;

[0037] The liquid-phase product contains C8 fatty amines.

[0038] Note: The liquid-phase product and the uncondensed gas enter the crude product tank together. After the liquid-phase product enters the crude product tank and stands for stratification (until the stratification is stable), an organic phase and an aqueous phase are obtained respectively. The organic phase is the crude product of C8 fatty amines; the uncondensed gas (ammonia, methane, hydrogen) is discharged to the water absorption system through the vent pipeline at the top of the crude product tank.

[0039] As an improvement to the method for preparing C8 fatty amines from C8 fatty alcohols of the present invention:

[0040] The C8 fatty alcohol is n-octanol, isooctanol, or sec-octanol;

[0041] The corresponding C8 fatty amines are n-octylamine (including n-octylamine, di-n-octylamine, tri-n-octylamine), isooctylamine (including isooctylamine, diisooctylamine) and sec-octylamine.

[0042] In summary, the present invention includes two major aspects: (1) the preparation of the catalyst; (2) the hydroamination of C8 fatty alcohols to produce fatty amines.

[0043] The content of the crude product of the present invention is analyzed by gas chromatography internal standard method. The conversion rate of the alcohol can be as high as over 95%, and the total selectivity of the amine can be as high as over 98%.

[0044] Alcohol conversion rate = (total alcohol concentration - remaining alcohol concentration) / total alcohol concentration * 100%;

[0045] Total amine selectivity = amine concentration / (total alcohol concentration - remaining alcohol concentration) * 100%.

[0046] The beneficial effects of the present invention are mainly reflected in:

[0047] 1. The present invention uses a Co / Cu / Mg / Zn supported metal catalyst to prepare C8 fatty amines. The reaction conditions are mild, the catalyst preparation process is simple, and it has good catalytic performance.

[0048] 2. The supported metal catalyst prepared by the present invention is applicable to the production of three types of C8 fatty amines: n-octylamine from n-octanol, isooctylamine from isooctanol, and sec-octylamine from sec-octanol. It has a high conversion rate, high catalyst activity, long operating life, the single-pass conversion rate of the raw material alcohol is higher than 95%, and the total amine selectivity is higher than 98%.

[0049] 3. By adjusting the production process conditions of the C8 fatty alcohol catalytic amination method, different ratios of n-octylamine, isooctylamine and sec-octylamine are produced as required.

[0050] 4. The continuous production idea of C8 fatty amines is good, the process is simple, the catalytic amination method process has the characteristics of being green and environmentally friendly, good atom economy, and theoretically the by-product is water, effectively reducing environmental pollution; especially without relying on an external hydrogen source, so the developed process route with high conversion rate, high selectivity and few by-products and the catalyst with high stability have extremely high industrial application value. Specific embodiments

[0051] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0052] Example 1-1

[0053] I. Preparation of the supported catalyst precursor

[0054] 1.1) Weigh 100 g of pseudo - boehmite and 5 g of sesbania powder, mix them evenly, then add 150 g of deionized water and 3 g of nitric acid, mix well, extrude the mixture into a certain shape with an extruder, air - dry it (until there is no obvious water stain on the surface), then dry it at 120 °C for 3 h, then heat it up to 300 °C in a muffle furnace and calcine for 2 h, and then heat it up to 550 °C and calcine for 10 h to obtain the catalyst support;

[0055] The heating rates for the above two temperature - rising steps are 3 °C / min and 5 °C / min respectively.

[0056] It can be detected by the conventional impregnation and saturated water - absorption method. The water - absorption rate of this catalyst support is about 60% - 90%.

[0057] 1.2) Prepare an aqueous solution of mixed nitrates according to the water - absorption rate of the support; set the active components after catalyst reduction to be 22.5% cobalt, 1.5% copper, 1.5% magnesium, and 0.5% zinc;

[0058] Dissolve 113.40 g of cobalt nitrate (containing 22.5 g of cobalt), 5.82 g of copper nitrate (containing 1.5 g of copper), 16.15 g of magnesium nitrate (containing 1.5 g of magnesium), and 2.32 g of zinc nitrate (containing 0.5 g of zinc) in 100 g of deionized water to prepare 237.69 g of mixed nitrate solution.

[0059] Pour 1 / 2 of the mixed nitrate solution into 74 g of the catalyst support, soak for 2 h, then air - dry the impregnated catalyst (until there is no obvious water stain on the surface), and place it in an oven at 120 °C for 3 h; then pour the remaining 1 / 2 of the mixed nitrate solution, soak for 2 h, then air - dry the impregnated catalyst (until there is no obvious water stain on the surface), place it in an oven at 120 °C for 3 h, and then calcine at 650 °C for 5 h; obtain the supported catalyst precursor. The contents of cobalt oxide, copper oxide, magnesium oxide, and zinc oxide in this supported catalyst precursor are 26.96%, 1.77%, 2.34%, and 0.59% respectively (that is, the active components after reduction are 22.5% cobalt, 1.5% copper, 1.5% magnesium, and 0.5% zinc), and the balance is the support.

[0060] Note: During the calcination process, cobalt nitrate, copper nitrate, magnesium nitrate, and zinc nitrate respectively form cobalt oxide, copper oxide, magnesium oxide, and zinc oxide. That is, metal oxides are attached to the supported catalyst.

[0061] II. Activation of the supported catalyst precursor (i.e., preparation of supported metal catalyst), and preparation of C8 fatty amines using C8 fatty alcohols as raw materials:

[0062] 2.1) Activation of the supported catalyst precursor:

[0063] The supported catalyst precursor prepared in the above steps was loaded into a Φ38 cm * 75 cm fixed-bed reactor. First, the catalyst was activated with hydrogen at 480 °C for 10 - 12 hours (continuously introducing hydrogen, controlling the pressure in the reactor at 0.05 Mpa, and the space velocity at 1000 h -1 ), and at this time, no more water was produced, so the activation was completed, and the resulting product was named the supported metal catalyst.

[0064] 2.2) Preparation of C8 fatty amine:

[0065] Using isooctanol and liquid ammonia as raw materials, that is, isooctanol is mixed with liquid ammonia and hydrogen through a metering pump, vaporized at 150 - 180 °C and then enters a fixed-bed reactor, and undergoes a catalytic ammoniation reaction under the action of the supported metal catalyst; the reaction pressure is 1.0 Mpa, the space velocity is 0.5 h -1 , the reaction temperature is 170 °C, and the molar ratio of ammonia: hydrogen: isooctanol is 5:5:1. The product obtained from the ammoniation reaction was analyzed by gas chromatography with an internal standard method. The conversion rate of isooctanol was 98.8%, and the total selectivity of amines was 99.5%.

[0066] The product obtained from the ammoniation reaction enters a condenser for condensation cooling and gas-liquid separation, respectively forming a liquid-phase product and uncondensed gas;

[0067] The liquid-phase product and the uncondensed gas enter a crude product tank together. After the liquid-phase product enters the crude product tank and stands for stratification (until the stratification is stable), an organic phase and an aqueous phase are obtained respectively. The organic phase is the crude product of C8 fatty amine; the uncondensed gas (ammonia, methane, hydrogen) is discharged to a water absorption system through the vent pipeline at the top of the crude product tank; ammonia is absorbed, and methane and hydrogen can be discharged naturally.

[0068] The organic phase can be subjected to conventional rectification treatment to obtain the product. The fraction collected at a vacuum degree of (-0.09 Mpa) and a temperature of 88 - 89 °C is isooctylamine, and the fraction collected at a temperature of 175 - 176 °C is diisooctylamine.

[0069] Examples 1-2 to 1-4

[0070] Change the "molar ratio of ammonia: hydrogen: isooctanol", "reaction temperature", "reaction pressure", and "reaction space velocity" to those described in Table 1 below, and the rest is the same as Example 1-1.

[0071] Table 1

[0072]

[0073] Examples 2-1 to 2-5

[0074] Change the raw material to "n-octanol", and change the "molar ratio of ammonia: hydrogen: n-octanol", "reaction temperature", "reaction pressure", and "reaction space velocity" as described in Table 2 below. The rest is the same as Example 1-1.

[0075] Table 2

[0076]

[0077] Examples 3-1 to 3-6

[0078] Change the raw material to "sec-octanol", and change the "molar ratio of ammonia: hydrogen: sec-octanol", "reaction temperature", "reaction pressure", and "reaction space velocity" as described in Table 3 below. The rest is the same as Example 1-1.

[0079] Table 3

[0080]

[0081] Example 4, continuous operation of the catalyst

[0082] Continue the reaction using the method described in Example 1-1. The rest is the same as Example 1-1. The number of consecutive operation days and the corresponding results are shown in Table 4 below.

[0083] Table 4

[0084]

[0085] Example 5, continuous operation of the catalyst

[0086] Continue the reaction using the method described in Example 2-4. The rest is the same as Example 2-4. The number of consecutive operation days and the corresponding results are shown in Table 5 below.

[0087] Table 5

[0088]

[0089] Example 6, continuous operation of the catalyst

[0090] Continue the reaction using the method described in Example 3-5. The rest is the same as Example 3-5. The number of consecutive operation days and the corresponding results are shown in Table 6 below.

[0091] Table 6

[0092]

[0093] Series of Example 7, change the active component as described in Table 7 below. The rest is the same as Example 1-1. The comparison of the obtained results with those of Example 1-1 is shown in Table 7 below.

[0094] Table 7

[0095]

[0096]

[0097] In the comparative example 1 series, the active components were changed as described in Table 8 below, and the rest were the same as in Example 1-1. The results were as shown in Table 8 below.

[0098] Table 8

[0099]

[0100] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A supported metal catalyst for preparing C8 fatty amines, characterized in that: The supported metal catalyst consists of active ingredients and catalyst carrier; the active ingredients consist of 0-30% cobalt, 0-5% copper, 0-4% magnesium and 0-3% zinc, accounting for 0-30% of the weight of the supported metal catalyst; the catalyst carrier is the balance.

2. The supported metal catalyst according to claim 1, characterized in that: The active component consists of 15% to 27.5% cobalt, 0.1% to 2.5% copper, 0.5% to 2.5% magnesium and 0.1% to 1.5% zinc, accounting for 15% to 27.5% of the weight of the supported metal catalyst.

3. The method for preparing a supported metal catalyst for preparing C8 fatty amines according to claim 1 or 2, characterized in that The following steps are involved: ①, after uniformly mixing pseudo-boehmite, sesbania powder, deionized water and nitric acid, extruding and molding, drying and then calcining, to obtain a catalyst carrier; The weight ratio of the pseudo-boehmite: sesbania powder: deionized water: nitric acid = 100: (5±0.5): (150±20): (3±0.3); ②, first dissolve the nitrate corresponding to the active ingredient in water to obtain a mixed nitrate solution; Then pour the mixed nitrate solution into the catalyst support obtained in step ① for impregnation, drying and calcination to obtain a supported catalyst precursor; ③. The supported catalyst precursor obtained in step ② is reduced with hydrogen at high temperature to obtain a supported metal catalyst.

4. The method for preparing a supported metal catalyst according to claim 3, characterized in that In step ①: The drying step is: drying at 120±20°C for 3±0.5h; The calcination is as follows: firstly heating the temperature to 300±30°C, calcining for 2±0.5 hours, and then heating the temperature to 550±50°C and calcining for 10±1 hours.

5. The method for preparing a supported metal catalyst according to claim 3 or 4, characterized in that In step ②: The number of times of impregnation-drying is 2 times; each time of impregnation-drying is: firstly, the impregnation time is 2±0.5 hours, and then the impregnated catalyst carrier is dried and placed in an oven at 110±10℃ for 3±0.5h; The calcination is carried out at 650±25° C. for 5±0.5 h.

6. The method for preparing a supported metal catalyst according to claim 5, characterized in that: In the step ③, the high temperature hydrogen reduction is: reduction at a pressure of 0.05 MPa and a temperature of 450-500° C. until no more water is generated.

7. A method for preparing C8 fatty amines using C8 fatty alcohol as raw material, characterized in that: Utilizing the supported metal catalyst as claimed in claim 1 or 2, comprising the following steps: 1) Loading a supported metal catalyst into a reactor; 2) C8 fatty alcohol is mixed with liquid ammonia and hydrogen through a metering pump, vaporized at 150-180°C, and then placed in a fixed bed reactor for catalytic amination reaction under the action of a supported metal catalyst; wherein the molar ratio of ammonia: hydrogen: C8 fatty alcohol is 2-10:5:1; the reaction temperature is 150-200°C; the reaction pressure is 0.1-2.0 MPa, and the reaction space velocity is 0.2-0.6 h -1 ; 3) The material obtained from the amination reaction in step 2) is subjected to condensation cooling and gas-liquid separation to form a liquid product and uncondensed gas; The liquid product contains C8 fatty amine.

8. The method for preparing C8 fatty amine using C8 fatty alcohol as raw material according to claim 7, characterized in that: C8 fatty alcohols are n-octanol, isooctyl alcohol, and sec-octanol; The corresponding C8 fatty amines are n-octylamine, isooctylamine and sec-octylamine.

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