CN120815526A

CN120815526A - Catalyst suitable for dehydration of alkyl alcohol to prepare alpha-olefins and preparation method thereof

Info

Publication number: CN120815526A
Application number: CN202510667490.9A
Authority: CN
Inventors: 袁华; 董正平; 黄浩; 马启和; 石永杰; 冯佳丽; 姜慧婧; 杨顺; 杨自玲; 刘春萌; 董国如; 杨露; 袁炜; 李瑞龙
Original assignee: National Energy Group Ningxia Coal Industry Co Ltd Coal Chemistry Industrial Technology Research Institute; National Energy Group Ningxia Coal Industry Co Ltd
Current assignee: National Energy Group Ningxia Coal Industry Co Ltd Coal Chemistry Industrial Technology Research Institute; National Energy Group Ningxia Coal Industry Co Ltd
Priority date: 2025-05-22
Filing date: 2025-05-22
Publication date: 2025-10-21

Abstract

The invention relates to the field of fine chemical engineering, in particular to a catalyst suitable for preparing alpha-olefin by alkyl alcohol dehydration and a preparation method thereof. The catalyst is characterized in that a carrier of the catalyst is a modified alumina carrier, a metal element in an active component of the catalyst is barium, wherein the content of the barium element in the catalyst calculated by BaO is 0.5-8wt%, the hardness of the catalyst is more than or equal to 30N, and the modified alumina carrier is obtained by forming acidified alumina emulsion through an oil ammonia column method and performing first roasting treatment. The catalyst has the advantages of simple preparation method, high hardness and excellent catalytic performance, can obtain extremely high yield in the reaction of preparing alpha-olefin by catalyzing the dehydration of alkyl alcohol, can catalyze the reaction for a long period, and is not easy to isomerise.

Description

Catalyst suitable for preparing alpha-olefin by alkyl alcohol dehydration and preparation method thereof

Technical Field

The invention relates to the field of fine chemical engineering, in particular to a catalyst suitable for preparing alpha-olefin by alkyl alcohol dehydration and a preparation method thereof.

Background

Alpha-olefins are an important chain olefin and are commonly used as high-value-added chemical products such as high-end polyolefin comonomers, poly alpha-olefins, alpha-alkenyl sulfonates and the like. For example, the most widely used alpha-octenes among the alpha-olefins are used as polyethylene comonomers for the synthesis of POE elastomers, and also for the production of plasticizers, surfactants and the principle of synthetic lubricating oils. The linear low-density polyethylene produced by the copolymerization of the alpha-octene has the characteristics of good machining performance, heat resistance, flexibility, transparency and the like, can effectively improve the tensile property, impact resistance, environmental stress cracking resistance of the polyethylene, and is obviously superior to other olefins in the aspects of improving the POE tear resistance, breaking strength and the like.

Currently, the industrial processes for preparing alpha-olefins are two types, wax cracking and ethylene catalytic oligomerization. Wherein, the wax cracking method has complex product components, and the content of alpha-olefin in the product is about 5-30wt%. In the method for synthesizing alpha-olefin by using ethylene to catalyze oligomerization, various even-numbered carbon olefins are more, and the even-numbered linear alpha-olefin is mainly C4-C40. Therefore, the wax cracking method and the ethylene catalytic oligomerization method have the problems of complex product components, low content of alpha-olefins with various carbon numbers in the product, high separation and purification difficulty and the like, and simultaneously, the production energy consumption and the cost for separating alpha-olefins with single carbon number are high. In addition to the two main processes for the preparation of alpha-olefins described above, patent CN201510684465.8 reports a process for the synthesis of alpha-olefins by catalytic conversion of synthesis gas, in which the synthesis gas preparation and purification processes are relatively complex. Patent CN201811336937.0 reports a method for preparing alpha-olefin by catalyzing synthesis gas with a Co-based catalyst in one step with high selectivity, but the preparation of the Co-based catalyst in the method is complex, and the problem of low yield of alpha-olefin exists. Patent CN201611098885.9 reports a method for preparing alpha-olefin by catalyzing carbon dioxide hydrogenation with an iron-based catalyst, but the reaction conditions in the method are more severe, and the yield of the alpha-olefin is also lower. Patent 202111262338.0 discloses a method for synthesizing alpha-olefin by catalyzing alcohol dehydration by using rare earth metal composite oxide as a catalyst, but the product alpha-olefin in the method is easy to isomerize and convert into internal olefin.

Aiming at the problems of the existing method for catalyzing and synthesizing the alpha-olefin, how to develop a catalyst and a method for catalyzing and synthesizing the alpha-olefin with high efficiency and simplicity has important significance.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provide a catalyst suitable for preparing alpha-olefin by dehydrating alkyl alcohol and a preparation method thereof. The catalyst has the advantages of simple preparation method and excellent catalytic performance, can obtain extremely high yield in the reaction of preparing the alpha-olefin by catalyzing the dehydration of the alkyl alcohol, can catalyze the reaction for a long period, and is not easy to isomerise.

In order to achieve the above purpose, the invention provides a catalyst suitable for preparing alpha-olefin by alkyl alcohol dehydration, wherein a carrier of the catalyst is a modified alumina carrier, a metal element in an active component of the catalyst is barium element, wherein the content of the barium element in the catalyst calculated by BaO is 0.5-8wt%, the hardness of the catalyst is more than or equal to 30N, and the modified alumina carrier is obtained by forming acidified alumina emulsion through an oil ammonia column method and performing first roasting treatment.

The second aspect of the invention provides a preparation method of the catalyst, which comprises the steps of loading a barium source on the modified alumina carrier and performing second roasting treatment to obtain the catalyst.

In a third aspect the present invention provides a process for the catalytic dehydration of an alkyl alcohol to produce an alpha-olefin, the process being carried out in the presence of a catalyst as described above.

The invention obtains the modified alumina carrier by a specific method, and carries the modified alumina carrier with barium element to obtain the corresponding catalyst, and the catalyst can perform long-period catalytic reaction by virtue of the high hardness characteristic of the catalyst. Meanwhile, the introduction of the barium element and proper roasting treatment can properly neutralize the surface acidity of the catalyst, so that extremely high alpha-olefin yield is obtained in the reaction of catalyzing the dehydration of alkyl alcohol to synthesize alpha-olefin, and the alpha-olefin is not easy to isomerise. The catalyst of the invention has simple preparation method and excellent catalytic performance, and can be continuously used for more than 30 days to still keep catalytic activity in a continuous fixed bed reactor for catalyzing the dehydration of alkyl alcohol to synthesize alpha-olefin.

Drawings

FIG. 1 is a scanning electron microscope image of a catalyst A1 obtained in preparation example 1;

FIG. 2 is a scanning electron microscope image of the catalyst A2 obtained in preparation example 2;

FIG. 3 is a scanning electron microscope image of the catalyst A3 obtained in preparation example 3;

FIG. 4 is a scanning electron microscope image of the catalyst A4 obtained in preparation example 4;

FIG. 5 is a scanning electron microscope image of the catalyst A5 obtained in preparation example 5;

FIG. 6 is an XRD pattern of catalysts A1 to A5 obtained in preparation examples 1 to 5;

FIG. 7 is a pyridine adsorption infrared chart of the catalyst A3 obtained in preparation example 3.

Detailed Description

The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.

The invention provides a catalyst suitable for preparing alpha-olefin by alkyl alcohol dehydration, wherein a carrier of the catalyst is a modified alumina carrier, a metal element in an active component of the catalyst is barium element, wherein the content of the barium element in the catalyst calculated by BaO is 0.5-8wt%, the hardness of the catalyst is more than or equal to 30N, and the modified alumina carrier is obtained by forming acidified alumina emulsion through an oil ammonia column method and performing first roasting treatment.

According to the invention, the barium element of the catalyst may be present in the form of barium oxide, barium carbonate or a combination thereof and is mainly distributed on the outer surface layer of the support.

Under the condition that only barium element is taken as an active component of the catalyst, the catalyst is loaded on the modified alumina carrier, and the neutralization of the acidity of the catalyst surface and the improvement of the yield and the selectivity of the reaction can be realized in the reaction for preparing alpha-olefin by catalyzing the dehydration of alkyl alcohol. Therefore, in practice, the catalyst of the present invention is preferably free of other active components and auxiliary components, that is, the catalyst of the present invention preferably uses only barium as an active component and contains no auxiliary components and other active components, and the modified alumina carrier of the present invention is combined to obtain the effect of improving the yield and selectivity of the preparation of alpha-olefin by dehydration of alkyl alcohol. Thus, preferably, the catalyst does not contain an adjunct component. It should be understood that in the present invention, the case of unavoidable impurities contained in the catalyst is not excluded.

According to the present invention, in order to provide a catalyst having better catalytic performance, the content of barium element in terms of BaO in the catalyst is preferably 1 to 5wt%, and may be, for example, a range between values of 1wt%, 3wt%, 4wt%, 5wt%, etc., and any of them.

According to the present invention, the high hardness characteristics of the catalyst of the present invention allow excellent long-period continuous catalytic performance, and preferably the catalyst has a hardness of 30 to 50N, for example, in the range between values of 30N, 33N, 38N, 45N, 50N, etc., and any of them.

According to the present invention, in order to enhance the catalyst performance, the modified alumina carrier prepared by the method of the present invention has a specific crystal form, and preferably, the modified alumina carrier is gamma-Al ₂O₃.

According to the present invention, the catalyst has excellent surface properties, and preferably the average particle diameter of the catalyst is 0.5 to 5mm, preferably 1 to 3mm, and may be, for example, in the range between values of 1mm, 2mm, 2.5mm, 3mm and the like and any of the values thereof.

Preferably, the specific surface area of the catalyst is 190-230m ²/g, preferably 200-220m ²/g, for example, it can be in the range between the values of 200m ²/g、210m²/g、215m²/g and 220m ²/g and any value thereof.

Preferably, the average pore diameter of the catalyst is from 6 to 18nm, preferably from 10 to 15nm, and may be, for example, in the range between 10nm, 12nm, 14nm and 15nm etc. and any of these values.

According to the invention, in order to obtain a modified alumina carrier with satisfactory performance, and further obtain an ideal catalyst, preferably, the preparation method of the acidified alumina emulsion comprises the steps of dispersing alumina raw materials into water to obtain an alumina suspension, and acidizing the alumina suspension with an acid solution to obtain the acidified alumina emulsion.

According to the invention, the raw materials of the alumina can be selected in a wider range, and in order to obtain gamma-Al ₂O₃ crystal form and improve the carrier performance, the raw materials of the alumina are preferably boehmite and/or pseudo-boehmite.

According to the invention, the solvent and the amount thereof may be selected within a wide range, and in order to obtain a better alumina suspension and to facilitate the subsequent steps, the amount of water is preferably 1.5-3g, preferably 2-2.5g, for example, may be in the range between values of 2g, 2.2g, 2.3g and 2.5g, and any of these values, relative to 1g of the alumina raw material.

In order to achieve better modification of the alumina according to the present invention, the choice and amount of the acid solution may be adjusted, preferably the acid in the acid solution is selected from one or more of nitric acid, hydrochloric acid, formic acid, acetic acid and perchloric acid. The solvent of the acid solution may be, for example, water.

Preferably, the concentration of the acid solution is 1-10wt%, preferably 3-6wt%, and may range between values such as 3wt%, 4wt%, 5wt%, and 6wt%, and any of these values.

Preferably, the acid solution is used in an amount of 0.005 to 0.05g, preferably 0.01 to 0.03g, relative to 1g of the alumina suspension, and may range between values such as 0.01g, 0.02g, 0.025g, and 0.03g, and any of these values.

According to the invention, in order to obtain a modified alumina carrier with better properties, the oil ammonia column method preferably comprises the steps of adding the acidified alumina emulsion into an oil ammonia column to form gel pellets, and standing and aging.

According to the present invention, preferably, the oil ammonia column is composed of aqueous ammonia, water and an organic solvent. Wherein the aqueous ammonia and the water are independent of each other, and the water does not include water in the aqueous ammonia. The oil ammonia column is contained in a cylindrical container, such as a cylinder.

According to the present invention, in order to facilitate the formation of gel beads, the concentration of the aqueous ammonia is preferably 15 to 40wt%, preferably 20 to 30wt%, and may range between values such as 20wt%, 25wt%, 28wt% and 30wt% and any of them.

Preferably, the organic solvent is selected from one or more of cyclohexane, n-hexane, n-heptane, toluene and n-octane, preferably one or more of cyclohexane, n-heptane and n-octane.

Preferably, the volume ratio of the ammonia water, water and organic solvent in the oil ammonia column is 1:2-6:0.01-0.1, preferably 1:3-5:0.02-0.06, and for example, the volume ratio can be in a range between values of 1:4:0.02, 1:3:0.04, 1:5:0.03 and 1:4:0.06 and any value thereof.

According to the present invention, the amount of the oil ammonia column may be selected within a wide range as long as the acidified alumina emulsion can be completely dropped to form gel beads. Preferably, the oil ammonia column is used in an amount of 5 to 30mL, preferably 10 to 20mL, relative to 1g of the acidified alumina emulsion, and may range between values such as 10mL, 12mL, 15mL, and 20mL, and any of these values.

According to the present invention, the conditions for the stationary aging may be selected within a wide range, and preferably, the conditions for the stationary aging include a temperature of 10 to 40 ℃ for 0.1 to 3 hours, and more preferably, the conditions for the stationary aging include a temperature of 20 to 30 ℃ such as a range between values of 20 ℃, 25 ℃, 28 ℃ and 30 ℃ and any value thereof, and a time of 0.5 to 2 hours such as a range between values of 0.5 hours, 1 hour, 1.5 hours and 2 hours and any value thereof, in order to improve the efficiency.

According to the invention, after the standing and ageing are finished, the gel pellets are separated and dried. Wherein, the drying condition can be 50-150 ℃ and 2-8h.

According to the invention, the gel pellets obtained by the method are subjected to first roasting treatment, and the modified alumina carrier can be obtained. In order to provide the resulting modified alumina carrier with better surface properties and hardness, the conditions for the first calcination treatment preferably include a temperature of 400 to 1000 ℃ for 1 to 12 hours, and more preferably the conditions for the first calcination treatment include a temperature of 500 to 800 ℃ such as values and any values thereof which may be 500 ℃, 600 ℃, 700 ℃, 800 ℃, and the like, and a time of 3 to 8 hours such as values and any values thereof which may be 3 hours, 5 hours, 6 hours, 8 hours, and the like.

According to the present invention, the preparation method of the modified alumina carrier is as described in the first aspect, and the present invention is not described herein.

According to the present invention, preferably, the method for supporting a barium source by the modified alumina carrier comprises immersing the modified alumina carrier in a solution of the barium source.

Preferably, the barium source is selected from one or more of barium nitrate, barium chloride, barium carbonate and barium sulfate, preferably barium nitrate and/or barium chloride.

Preferably, the concentration of the solution of the barium source is 0.1-3wt%, preferably 0.2-1wt%, for example, may range between values of 0.2wt%, 0.5wt%, 0.8wt% and 1wt%, etc., and any value thereof. The solvent used in the solution of the barium source may be, for example, water.

Preferably, the time of the impregnation is 0.5-8h, preferably 3-6h, and may be, for example, in the range between values of 3h, 4h, 5h and 6h, and any of these values.

According to the invention, after the impregnation process has ended, the impregnation may be evaporated to dryness under vacuum (for example at 60-90 ℃) and dried (drying conditions may generally be 80-150 ℃ for 4-24 hours), so as to facilitate the subsequent second calcination treatment.

According to the present invention, in order to better neutralize the acidity of the catalyst surface to a desired range and thereby improve the selectivity of the catalyst in the reaction for preparing alpha-olefins by catalyzing the dehydration of alkyl alcohols, preferably, the conditions of the second calcination treatment include a temperature of 400 to 800 ℃ for 2 to 8 hours, more preferably, the conditions of the second calcination treatment include a temperature of 500 to 700 ℃ such as a range between values of 500 ℃, 600 ℃, 650 ℃, 700 ℃ and the like and any values thereof, and a time of 4 to 6 hours such as a range between values of 4 hours, 5 hours, 5.5 hours, 6 hours and the like and any values thereof.

According to the invention, preferably, the method for preparing alpha-olefin by catalyzing the dehydration of alkyl alcohol adopts a continuous fixed bed reactor with higher efficiency.

According to the present invention, in order to obtain a higher reaction yield, the temperature of the continuous fixed bed reactor is preferably set to 250 to 350 ℃, preferably 280 to 330 ℃, and may be, for example, a range between values of 280 ℃, 300 ℃, 320 ℃ and 330 ℃ and any of the values thereof.

According to the invention, the source of the alkyl alcohol can be selected in a wider range, wherein a certain amount of alkyl alcohol compounds are always contained in the Fischer-Tropsch synthesis distillate oil of the coalification industry, and the alkyl alcohol compounds are separated from the Fischer-Tropsch oil and used for preparing the alpha-olefin, so that the high value-added utilization of the alkyl alcohol can be realized, and the yield increase of the alpha-olefin can be realized to a certain extent.

According to the invention, in order to achieve better reaction effect and obtain higher yield, preferably, the sample injection raw material of the continuous fixed bed reactor is a mixed solution of alkyl alcohol and alkane. Wherein the alkyl alcohol may be a C6-C20 alkyl alcohol, such as n-hexanol, n-heptanol, n-octanol, n-decanol, n-undecanol, n-dodecanol, n-tetradecanol, etc. The alkane may be a C6-C20 alkane such as n-hexane, n-heptane, n-decane, n-dodecane, etc., as the solvent for the alkyl alcohol.

Preferably, the alkyl alcohol is contained in the mixture in an amount of 1 to 15wt%, preferably 2 to 10wt%, for example, it may be 2wt%, 3wt%, 5wt%, 8wt% and 10wt% or any range therebetween.

According to the present invention, in order to control the reaction progress, it is preferable that the continuous fixed bed reactor has a sample injection rate of 0.2 to 2mL/min, preferably 0.5 to 1.5mL/min, and for example, may have values of 0.6mL/min, 0.8mL/min, 1mL/min, 1.5mL/min, etc., and any value thereof.

According to the present invention, in order to achieve a better catalytic effect, it is preferable that the catalyst is charged in the continuous fixed bed reactor in an amount of 10 to 50g, preferably 20 to 40g, for example, in a range between values of 20g, 25g, 33g and 40g and any of them, with respect to a sample introduction rate of 1 mL/min.

The present invention will be described in detail by examples.

In the following examples, the apparatus used was conventional in the art, the procedure used was conventional in the art, and the raw materials, reagents, etc. used were commercially available. Wherein n-octanol, n-hexanol, n-heptanol, n-decanol, n-undecanol, n-dodecanol and n-tetradecanol are isolated from a coalification Fischer-Tropsch synthesis distillate.

Preparation examples 1 to 5

Preparation example 1. 130g of pseudo-boehmite was dispersed in 285g of deionized water and mixed with stirring to obtain an alumina suspension. 8.6g of a 5wt% aqueous nitric acid solution was added dropwise to the alumina suspension for acidification to give an acidified alumina emulsion. 100mL of 25wt% ammonia water and 400mL of deionized water were added to the cylinder, and 3mL of cyclohexane was added to form a thin oily liquid surface, giving an oily ammonia column. And (3) dripping the acidified alumina emulsion into an oil ammonia column to form gel pellets, standing and aging for 0.5h at 25 ℃, separating the gel pellets, drying for 5h at 100 ℃, and roasting the gel pellets for 5h at 600 ℃ to obtain the modified alumina carrier (gamma-Al ₂O₃ crystal form). A certain amount of modified alumina carrier is immersed in a certain amount of 0.3wt% barium nitrate aqueous solution for 4 hours, evaporated to dryness under a vacuum condition at 70 ℃, dried for 12 hours at 120 ℃, and baked for 5 hours at 600 ℃ to obtain a catalyst A1 with the barium element content (calculated by BaO) of 1 wt%. The hardness of the catalyst A1 was 35N, the average particle diameter was 2.4mm, the specific surface area was 215m ²/g, and the average pore diameter was 13nm.

Preparation example 2 catalyst A2 having a barium element content (in terms of BaO) of 2% by weight was produced by adjusting the amount of the 0.3% by weight aqueous solution of barium nitrate in accordance with the method of preparation example 1. The hardness of the catalyst A2 was 38N, the average particle diameter was 2.5mm, the specific surface area was 216m ²/g, and the average pore diameter was 12.8nm.

PREPARATIVE EXAMPLE 3 catalyst A3 having a barium element content (in terms of BaO) of 3% by weight was prepared by adjusting the amount of the 0.3% by weight aqueous solution of barium nitrate in accordance with the method of PREPARATIVE EXAMPLE 1. The hardness of the catalyst A3 was 33N, the average particle diameter was 2.5mm, the specific surface area was 212m ²/g, and the average pore diameter was 11.8nm.

PREPARATION EXAMPLE 4 catalyst A4 having a barium element content (in terms of BaO) of 4% by weight was prepared by adjusting the amount of the 0.3% by weight aqueous solution of barium nitrate in accordance with the method of preparation example 1. The hardness of the catalyst A4 was 31N, the average particle diameter was 2.3mm, the specific surface area was 209m ²/g, and the average pore diameter was 10.9nm.

PREPARATION EXAMPLE 5 catalyst A5 having a barium element content (in terms of BaO) of 5% by weight was prepared by adjusting the amount of the 0.3% by weight aqueous solution of barium nitrate in accordance with the method of preparation example 1. The hardness of the catalyst A5 was 32N, the average particle diameter was 2.2mm, the specific surface area was 206m ²/g, and the average pore diameter was 10.8nm.

The scanning electron microscope images of the catalysts A1 to A5 obtained in preparation examples 1 to 5 are shown in FIGS. 1 to 5, respectively, and it can be seen that the microstructure of the catalysts A1 to A5 is amorphous powder.

The XRD patterns of catalysts A1-A5 obtained in preparation examples 1-5 are shown in FIG. 6, and it can be seen that catalysts A1-A5 have characteristic diffraction peaks of gamma-Al ₂O₃.

The pyridine adsorption infrared diagram of the catalyst A3 obtained in preparation example 3 is shown in FIG. 7, and it can be seen that the catalyst A3 has no B acid site.

Preparation example 6

130G of pseudo-boehmite was dispersed in 260g of deionized water and stirred and mixed to obtain an alumina suspension. 7.8g of a 3wt% aqueous hydrochloric acid solution was added dropwise to the alumina suspension for acidification to give an acidified alumina emulsion. 100mL of 28wt% aqueous ammonia and 300mL of deionized water were added to the cylinder, and 4mL of n-octane was added to form a thin oily liquid surface, giving an oily ammonia column. And (3) dripping the acidified alumina emulsion into an oil ammonia column to form gel pellets, standing and aging for 1h at 20 ℃, separating the gel pellets, drying for 3h at 120 ℃, and roasting the gel pellets for 3h at 750 ℃ to obtain the modified alumina carrier (gamma-Al ₂O₃ crystal form). A certain amount of modified alumina carrier is immersed in a certain amount of 0.5wt% barium nitrate aqueous solution for 6 hours, redundant impregnating solution is evaporated to dryness under the vacuum condition of 80 ℃, the impregnating solution is dried for 6 hours at 100 ℃, and the catalyst A6 with the barium element content (calculated by BaO) of 3wt% is obtained after roasting for 3 hours at 500 ℃. The hardness of the catalyst A6 was 34N, the average particle diameter was 2.4mm, the specific surface area was 211m ²/g, and the average pore diameter was 12nm.

Preparation example 7

130G of pseudo-boehmite was dispersed in 320g of deionized water, and the mixture was stirred and mixed to obtain an alumina suspension. 5g of a 4wt% aqueous acetic acid solution was added dropwise to the alumina suspension for acidification to give an acidified alumina emulsion. 100mL of 28wt% aqueous ammonia and 450mL of deionized water were added to the cylinder, and 6mL of n-heptane was added to form a thin oily liquid surface, giving an oily ammonia column. And (3) dripping the acidified alumina emulsion into an oil ammonia column to form gel pellets, standing and aging for 1.5 hours at 30 ℃, separating the gel pellets, drying for 4 hours at 120 ℃, and roasting the gel pellets for 8 hours at 500 ℃ to obtain the modified alumina carrier (gamma-Al ₂O₃ crystal form). A certain amount of modified alumina carrier is immersed in a certain amount of 1wt% barium nitrate aqueous solution for 3 hours, redundant impregnating solution is evaporated under the vacuum condition of 90 ℃, the excessive impregnating solution is dried for 16 hours at 140 ℃, and the catalyst A7 with the barium element content (calculated by BaO) of 3wt% is obtained after roasting for 4 hours at 700 ℃. The hardness of the catalyst A7 was 32N, the average particle diameter was 2.5mm, the specific surface area was 213m ²/g, and the average pore diameter was 12.6nm.

Preparation examples 8 to 9

Preparation example 8 catalyst A8 having a barium element content (in terms of BaO) of 0.5% by weight was produced by adjusting the amount of the 0.3% by weight aqueous solution of barium nitrate in accordance with the method of preparation example 1. The hardness of the catalyst A8 was 30N, the average particle diameter was 2.5mm, the specific surface area was 218m ²/g, and the average pore diameter was 12.2nm.

PREPARATIVE EXAMPLE 9 according to the method of PREPARATIVE EXAMPLE 1, catalyst A9 having a barium element content (in terms of BaO) of 8% by weight is prepared by adjusting the amount of the 0.3% by weight aqueous solution of barium nitrate. The hardness of catalyst A9 was 32N, the average particle diameter was 2.3mm, the specific surface area was 205m ²/g, and the average pore diameter was 11nm.

Example 1

20G of catalyst A1 is filled in a continuous fixed bed reactor, the reaction temperature is set to be 300 ℃, the sample injection rate of n-octanol/n-decane mixed liquid with the n-octanol content of 3wt% is set to be 0.6mL/min, the reacted materials are collected at the outlet of the continuous fixed bed reactor, and the analysis by a gas chromatograph is carried out to obtain the n-octanol conversion rate of 99% and the alpha-n-octene selectivity of 99.3%.

Examples 2 to 5

Example 2 the procedure of example 1 was followed except that catalyst A1 was replaced with catalyst A2 and the final analysis by gas chromatograph gave a conversion of 99.2% of n-octanol and a selectivity of 99.5% for alpha-n-octene.

Example 3 the procedure of example 1 was followed except that catalyst A1 was replaced with catalyst A3 and the final analysis by gas chromatograph gave a conversion of 99.1% of n-octanol and a selectivity of 99.8% for alpha-n-octene.

Example 4 the procedure of example 1 was followed except that catalyst A1 was replaced with catalyst A4 and the final analysis by gas chromatograph gave a conversion of 99.4% of n-octanol and a selectivity of 99.5% for alpha-n-octene.

Example 5 the procedure of example 1 was followed except that catalyst A1 was replaced with catalyst A5 and the final analysis by gas chromatograph gave a conversion of 99.8% of n-octanol and a selectivity of 99.3% for alpha-n-octene.

Example 6

According to the method of example 1, except that the catalyst A1 was replaced with the catalyst A3, the reaction temperature was set at 315 ℃, and the n-octanol conversion was 99.9% and the α -n-octene selectivity was 99.8% as finally analyzed by gas chromatograph.

Example 7

According to the method of example 1, except that the catalyst A1 was replaced with the catalyst A3, the reaction temperature was set at 330 ℃, and the n-octanol conversion was 100% and the α -n-octene selectivity was 99.9% as finally analyzed by gas chromatograph.

Example 8

According to the method of example 1, except that the catalyst A1 was replaced with the catalyst A3, the reaction temperature was set at 330℃and the sample injection rate of the n-octanol/n-decane mixed liquid having the n-octanol content of 3% by weight was set at 0.8mL/min, the conversion of n-octanol was 100% and the selectivity of α -n-octene was 99.8% as finally analyzed by a gas chromatograph.

Example 9

According to the method of example 1, except that the catalyst A1 was replaced with the catalyst A3, the reaction temperature was set at 330℃and the sample injection rate of the n-octanol/n-decane mixed liquid having the n-octanol content of 3wt% was set at 1mL/min, the conversion of n-octanol was 99% and the selectivity of α -n-octene was 99.9% as finally obtained by analysis by a gas chromatograph.

Example 10

According to the method of example 1, except that the catalyst A1 was replaced with the catalyst A3, the reaction temperature was set at 330℃and the sample injection rate of the n-octanol/n-decane mixed liquid having the n-octanol content of 5% by weight was set at 0.6mL/min, the conversion of n-octanol was 98% and the selectivity of α -n-octene was 99.9% as finally analyzed by a gas chromatograph.

Example 11

According to the method of example 1, except that the catalyst A1 was replaced with the catalyst A3, the reaction temperature was set at 330℃and the sample injection rate of the n-hexanol/n-decane mixed solution having a n-hexanol content of 3wt% was set at 0.6mL/min, the conversion of n-hexanol was 100% and the selectivity of α -hexene was 99.8% as finally analyzed by a gas chromatograph.

Example 12

According to the method of example 1, except that the catalyst A1 was replaced with the catalyst A3, the reaction temperature was set at 330℃and the sample injection rate of the n-heptanol/n-decane mixed solution having an n-heptanol content of 3% by weight was set at 0.6mL/min, the conversion of n-heptanol was 99.9% and the selectivity of α -n-heptene was 99.8% as finally obtained by analysis with a gas chromatograph.

Example 13

According to the method of example 1, except that the catalyst A1 was replaced with the catalyst A3, the reaction temperature was set at 330 ℃, the sample rate of the n-decanol/n-decane mixed solution having a n-decanol content of 3wt% was set at 0.6mL/min, and finally the n-decanol conversion was 99.7% and the α -n-decene selectivity was 99.9% by analysis with a gas chromatograph.

Example 14

According to the method of example 1, except that the catalyst A1 was replaced with the catalyst A3, the reaction temperature was set at 330℃and the sample injection rate of the n-undecyl alcohol/n-decane mixed solution having an n-undecyl alcohol content of 3% by weight was set at 0.6mL/min, the conversion of n-undecyl alcohol was 99.8% and the selectivity of α -n-undecene was 99.9% as finally analyzed by a gas chromatograph.

Example 15

According to the method of example 1, except that the catalyst A1 was replaced with the catalyst A3, the reaction temperature was set at 330℃and the sample injection rate of the n-dodecanol/n-decane mixed solution having an n-dodecanol content of 3% by weight was set at 0.6mL/min, the conversion of n-dodecanol was 100% and the selectivity of α -n-dodecene was 99.9% as finally obtained by analysis with a gas chromatograph.

Example 16

According to the method of example 1, except that the catalyst A1 was replaced with the catalyst A3, the reaction temperature was set at 330℃and the sample injection rate of the n-tetradecyl alcohol/n-decane mixed solution having the n-tetradecyl alcohol content of 3wt% was set at 0.6mL/min, the conversion of n-tetradecyl alcohol was 100% and the selectivity of α -n-tetradecene was 99.8% as finally obtained by analysis by a gas chromatograph.

Example 17

According to the method of example 7, the reaction of catalyzing the dehydration of n-octanol to prepare alpha-octene is continuously carried out for 30 days, the n-octanol conversion rate is 99.8% and the alpha-octene selectivity is 99.9% by analysis of a gas chromatograph on the 30 th day, and the catalyst has excellent long-period catalytic capability, excellent performance and lasting stability.

Example 18

According to the method of example 1, except that the catalyst A1 was replaced with the catalyst A6, the n-octanol conversion was 99.7% and the alpha-octene selectivity was 99.8% as finally analyzed by gas chromatograph

Example 19

According to the method of example 1, except that the catalyst A1 was replaced with the catalyst A7, the n-octanol conversion was 99.5% and the alpha-octene selectivity was 99.7% as finally analyzed by gas chromatograph.

Example 20

According to the method of example 1, except that the catalyst A1 was replaced with the catalyst A8, the n-octanol conversion was finally obtained by analysis by gas chromatograph to be 95.1%, and the alpha-octene selectivity was 97.1%.

Example 21

According to the method of example 1, except that the catalyst A1 was replaced with the catalyst A9, the n-octanol conversion was 94.3% and the α -octene selectivity was 97.8% as finally analyzed by gas chromatograph.

Comparative example 1

130G of pseudo-boehmite was dispersed in 285g of deionized water and mixed with stirring to obtain an alumina suspension. 8.6g of a 5wt% aqueous nitric acid solution was added dropwise to the alumina suspension for acidification to give an acidified alumina emulsion. The acidified alumina emulsion is dried for 10 hours at 120 ℃, and the solid obtained after drying is roasted for 5 hours at 600 ℃ to obtain the modified alumina carrier (gamma-Al ₂O₃ crystal form). Tabletting and molding the modified alumina carrier by using a press, crushing, sieving and separating by using a 40-mesh sieve for later use, soaking the modified alumina carrier in a barium nitrate aqueous solution with the concentration of 0.3wt percent for 4 hours, evaporating excessive soaking liquid under the vacuum condition with the concentration of 70 ℃, drying at 120 ℃ for 12 hours, and roasting at 600 ℃ for 6 hours to obtain the catalyst B1 with the concentration of 1wt percent of barium (calculated as BaO). The hardness of the catalyst B1 was 23N, the average particle diameter was 2.6mm, the specific surface area was 203m ²/g, and the average pore diameter was 11nm.

20G of catalyst B1 is filled in a continuous fixed bed reactor, the reaction temperature is set to be 300 ℃, the sample injection rate of n-octanol/n-decane mixed liquid with the n-octanol content of 3wt% is set to be 0.6mL/min, the reacted materials are collected at the outlet of the continuous fixed bed reactor, and the analysis by a gas chromatograph is carried out to obtain the n-octanol conversion rate of 93.7% and the alpha-octene selectivity of 94.1%.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

Claims

1. A catalyst suitable for preparing alpha-olefin by alkyl alcohol dehydration is characterized in that a carrier of the catalyst is a modified alumina carrier, a metal element in an active component of the catalyst is barium element, wherein the content of the barium element in the catalyst calculated by BaO is 0.5-8wt%, the hardness of the catalyst is more than or equal to 30N, and the modified alumina carrier is obtained by forming acidified alumina emulsion through an oil ammonia column method and performing first roasting treatment.

2. The catalyst of claim 1, wherein the catalyst is free of adjunct components;

And/or the content of barium element in the catalyst calculated by BaO is 1-5wt%;

and/or the hardness of the catalyst is 30-50N;

And/or, the modified alumina carrier is gamma-Al ₂O₃;

and/or the catalyst has an average particle size of 0.5 to 5mm, preferably 1 to 3mm;

And/or the specific surface area of the catalyst is 190-230m ²/g, preferably 200-220m ²/g;

And/or the average pore diameter of the catalyst is 6-18nm, preferably 10-15nm.

3. The catalyst according to claim 1 or 2, wherein the preparation method of the acidified alumina emulsion comprises dispersing alumina raw material in water to obtain alumina suspension, and acidifying the alumina suspension with acid solution to obtain the acidified alumina emulsion;

preferably, the alumina raw material is boehmite and/or pseudo-boehmite;

preferably, the amount of water is 1.5 to 3g, preferably 2 to 2.5g, relative to 1g of the alumina raw material;

Preferably, the acid in the acid solution is selected from one or more of nitric acid, hydrochloric acid, formic acid, acetic acid and perchloric acid, preferably nitric acid and/or hydrochloric acid;

preferably, the concentration of the acid solution is 1-10wt%, preferably 3-6wt%;

preferably, the acid solution is used in an amount of 0.005 to 0.05g, preferably 0.01 to 0.03g, relative to 1g of the alumina suspension.

4. The catalyst according to any one of claims 1 to 3, wherein the oil ammonia column method comprises adding the acidified alumina emulsion to an oil ammonia column to form gel pellets and aging by standing;

preferably, the oil ammonia column consists of ammonia water, water and an organic solvent;

preferably, the concentration of the ammonia water is 15-40wt%, preferably 20-30wt%;

Preferably, the organic solvent is selected from one or more of cyclohexane, n-hexane, n-heptane, toluene and n-octane, preferably one or more of cyclohexane, n-heptane and n-octane;

preferably, the volume ratio of the ammonia water, water and organic solvent in the oily ammonia water column is 1:2-6:0.01-0.1, preferably 1:3-5:0.02-0.06;

Preferably, the oil ammonia column is used in an amount of 5 to 30mL, preferably 10 to 20mL, relative to 1g of the acidified alumina emulsion;

Preferably, the condition of standing and aging comprises a temperature of 10-40 ℃ for 0.1-3h, and more preferably, the condition of standing and aging comprises a temperature of 20-30 ℃ for 0.5-2h.

5. The catalyst according to any one of claims 1 to 4, wherein the conditions of the first calcination treatment comprise a temperature of 400 to 1000 ℃ for a time of 1 to 12 hours, more preferably the conditions of the first calcination treatment comprise a temperature of 500 to 800 ℃ for a time of 3 to 8 hours.

6. The method for preparing a catalyst according to any one of claims 1 to 5, wherein the method comprises loading a barium source on the modified alumina carrier and performing a second calcination treatment to obtain the catalyst.

7. The method according to claim 6, wherein the method for supporting a barium source on the modified alumina carrier comprises immersing the modified alumina carrier in a solution of the barium source;

Preferably, the barium source is selected from one or more of barium nitrate, barium chloride, barium carbonate and barium sulfate, preferably barium nitrate and/or barium chloride;

preferably, the concentration of the solution of the barium source is 0.1-3wt%, preferably 0.2-1wt%;

Preferably, the time of the impregnation is between 0.5 and 8 hours, preferably between 3 and 6 hours;

Preferably, the conditions of the second roasting treatment comprise a temperature of 400-800 ℃ for 2-8 hours, and more preferably, the conditions of the second roasting treatment comprise a temperature of 500-700 ℃ for 4-6 hours.

8. A process for the preparation of alpha-olefins by catalytic dehydration of alkyl alcohols, characterized in that it is carried out in the presence of a catalyst according to any of claims 1 to 5.

9. The process of claim 8, wherein the process employs a continuous fixed bed reactor;

Preferably, the temperature of the continuous fixed bed reactor is set to 250-350 ℃, preferably 280-330 ℃.

10. The method of claim 9, wherein the sample feed of the continuous fixed bed reactor is a mixed solution of alkyl alcohol and alkane;

Preferably, the alkyl alcohol is present in the mixture in an amount of 1 to 15wt%, preferably 2 to 10wt%;

Preferably, the sample injection rate of the continuous fixed bed reactor is 0.2-2mL/min, preferably 0.5-1.5mL/min;

preferably, the catalyst is loaded in the continuous fixed bed reactor in an amount of 10 to 50g, preferably 20 to 40g, relative to a sample rate of 1 mL/min.