CN112678853B - Flaky grain boehmite and preparation method thereof - Google Patents
Flaky grain boehmite and preparation method thereof Download PDFInfo
- Publication number
- CN112678853B CN112678853B CN201910990737.5A CN201910990737A CN112678853B CN 112678853 B CN112678853 B CN 112678853B CN 201910990737 A CN201910990737 A CN 201910990737A CN 112678853 B CN112678853 B CN 112678853B
- Authority
- CN
- China
- Prior art keywords
- boehmite
- acid
- drying
- crystal
- grain
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
Flake-grain boehmite, D of crystal grain thereof (200) /D (002) ＝0.5～1.5，D (020) L = 0.05-0.6, wherein l =1/2[D (200) 2 +D (002) 2 ] 1/2 Said D is (020) 、D (200) And D (002) The crystal grain sizes calculated from the Sherrer formula are respectively from the half widths of diffraction peaks in the directions of the (020) crystal plane, (200) crystal plane and (002) crystal plane in the X-ray diffraction curve of boehmite. The boehmite has regular grain structure and uniform grain size, and is prepared by roasting 2 O 3 Has more strong acid and medium strong acid.
Description
Technical Field
The invention relates to hydrated alumina and a preparation method thereof, in particular to flaky grain boehmite and a preparation method thereof.
Background
γ-Al 2 O 3 Is one of heterogeneous catalyst carriers with wide application, in particular to the fields of petroleum refining, petrochemical industry and fine chemical industry, such as the carrier of catalytic hydrogenation, catalytic reforming and isomerization catalysts. Its large specific surface area (generally greater than 150 m) 2 /g) facilitates dispersion of the active metal component, and the surface acidity also provides a part of the acid center for certain catalytic reaction processes (such as catalytic reforming, isomerization of lower alkanes, etc.). gamma-Al 2 O 3 As a catalytic material, the macroscopic physical properties and catalytic performance in various fields have been studied, and gamma-Al has been studied 2 O 3 The surface properties are relatively poorly studied. In recent years, researchers have found that gamma-Al 2 O 3 Especially gamma-Al 2 O 3 The type and proportion of exposed crystal faces of the support will also affect the catalytic performanceCan, therefore, for gamma-Al 2 O 3 The exposed crystal face of the carrier crystal grain is regulated and controlled, which is a new way for improving the performance of the catalyst.
γ-Al 2 O 3 Is obtained by roasting boehmite at a certain temperature, and the existing research shows that the boehmite is converted into gamma-Al 2 O 3 The transformation process is a topological process of short-range rearrangement of Al and O atoms on the structure, and during the transformation process, the crystal grain appearance of boehmite is in gamma-Al 2 O 3 Well maintained, and exposed crystal face of boehmite and gamma-Al 2 O 3 Have a defined correspondence between the exposed crystal planes. According to the findings of Digne et al (Digne M, sautet P, raybaud P, et al Structure and stability of aluminum hydroxides: a the electronic study [ J)]J Phys Chem B,2002,106 (20): 5155-5162), boehmite is converted to γ -Al 2 O 3 In the process of (2), the (010) crystal face and the (100) crystal face of the boehmite crystal grain are converted into gamma-Al 2 O 3 The (110) crystal face of boehmite crystal grain, the (101) crystal face of boehmite crystal grain are converted into gamma-Al 2 O 3 The (111) crystal face of boehmite crystal grain, the (001) crystal face of boehmite crystal grain is converted into gamma-Al 2 O 3 The (100) crystal plane of (c). Therefore, it is desired to realize para-gamma-Al 2 O 3 The precise regulation and control of the crystal grain exposed crystal face is fundamentally in the precise regulation and control of the boehmite crystal grain exposed crystal face, namely the morphology of the boehmite crystal grain.
The existing research finds that in the preparation process of boehmite, the step which plays a decisive role in the crystal grain morphology is the aging stage of the aluminum hydroxide slurry, in the aging process, boehmite crystal grains grow in a liquid phase environment, the coordination structure of atoms on the surface of solid phase crystal grains and atoms in a bulk phase has a large difference, the atoms on the surface of the crystal grains are metastable, and the driving force of the crystal grain growth is to minimize the surface free energy, so that the crystal face with the lowest surface free energy becomes the dominant crystal face of the crystal grains. According to the Gibbs adsorption law, during the growth or dissolution of the crystal grains, the solid-phase crystal grains automatically adsorb or desorb species which can reduce their surface energy from or to the liquid phase, thereby maintaining the surface energy of the whole crystal grains at a minimum.
The addition of a grain structure regulator during the aging process of the aluminum hydroxide slurry is the most common method for regulating the morphology of boehmite grains. Chiche et Al use Al (NO) 3 -NaAlO 2 Precipitation method for preparing boehmite (Chiche D, chizallet C, duruthy O, et al, growth of boehmite particles in the presence of xylene, collagen oriented by the new effect of hydroxide bonding [ J]Phys Chem Phys,2009,11 (47): 11310-11323), the morphology of boehmite nanoparticles was controlled by adding polyol to the aluminum hydroxide slurry. The results show that the polyol molecules are easily adsorbed on the (101) crystal face of the boehmite crystal grains after being added, the surface tension between the crystal face and the liquid phase is reduced, and the exposure ratio of the (101) crystal face is increased while the boehmite crystal grains are reduced.
CN104150513A discloses a strip-shaped crystal grain boehmite and a preparation method thereof, wherein the width of the strip-shaped crystal grain boehmite is 3-6 nm, and the length is 20-107 nm. The preparation method of the strip-shaped grain boehmite comprises the following steps of 5 ～C 7 The alkoxy aluminum is hydrolyzed under the conditions that the molar ratio of water to the alkoxy aluminum is 3-6 and the temperature is 80-100 ℃, the serous fluid obtained after hydrolysis is placed in a closed container, is aged for 2-48 hours under the conditions that the temperature is 100-200 ℃ and the pressure is 0.2-1.0 MPa, and the alcohol generated by hydrolysis is separated to obtain the strip-shaped crystal grain boehmite. The preparation method of the strip-shaped crystal grain boehmite is simple and low in cost, only self-synthesized substances are used in the preparation process, other organic matters are not required to be added, and the preparation method is suitable for large-scale production.
CN105084397A is a further improvement of the method disclosed in CN104150513A, the mixture of aluminum hydroxide slurry obtained by hydrolyzing alkoxy aluminum and alcohol is aged in a closed container for 2-72 hours at 60-250 ℃ and under the pressure of 0.2-1.0 MPa, the aged slurry is directly dried, and the alcohol is recovered in the drying process. The method can reduce the aggregation of the strip boehmite grains, and has simple process and low cost.
CN104724741A discloses a preparation method of flake alumina, which adopts an aluminum source, an amine organic matter and an auxiliary agent as raw materials, prepares a solution according to a certain proportion, heats and stirs the solution, volatilizes the solution, condenses the solution and pyrolyzes the solution to obtain precursor powder, wherein the aluminum source is a water-soluble inorganic aluminum salt, such as aluminum chloride, aluminum nitrate or aluminum sulfate; then reacting the precursor powder for 2-4 hours at 800-1700 ℃ in a flowing air atmosphere; finally, the flaky alumina with the granularity of 3-8 mu m and the diameter/thickness ratio of 25-80 is obtained.
CN105347377A discloses a preparation method of high-purity flaky alumina, which comprises the steps of taking high-purity aluminum isopropoxide with the purity of 99.999%, pure water and isopropanol as main raw materials, taking ammonium bifluoride or ammonium fluoride as a crystal morphology control agent, dissolving the high-purity aluminum isopropoxide in the isopropanol to prepare a solution A, preparing the pure water, the isopropanol and the ammonium bifluoride into a solution B, gradually adding the solution A into the solution B at a certain dropping speed, reacting under the action of heating and stirring to generate hydrated alumina, and sequentially filtering, drying and roasting to obtain the high-purity flaky alumina. The thickness of the high-purity flaky alumina crystal grain prepared by the method is less than or equal to 1.0 mu m, and the radial size is 5-20 mu m.
The above patents propose several methods for preparing boehmite or alumina with specific crystal grain morphology, the adopted crystal grain morphology control agent is amine organic matter or ammonium compound, the cost is high, and a large amount of waste gas is easy to generate in the production process.
Disclosure of Invention
The invention aims to provide flaky grain boehmite and a preparation method thereof, wherein the boehmite has a regular grain structure and uniform grain size, and is prepared by roasting the boehmite 2 O 3 Has more strong acid and medium strong acid.
The flake-shaped crystal grain boehmite provided by the invention and D of the crystal grain thereof (200) /D (002) ＝0.5～1.5，D (020) L = 0.05-0.6, wherein l =1/2[D (200) 2 +D (002) 2 ] 1/2 Said D is (020) 、D (200) And D (002) The crystal grain sizes calculated by the Sherrer formula are respectively based on the half-peak widths of diffraction peaks in the directions of the (020) crystal plane, (200) crystal plane and the (002) crystal plane in the X-ray diffraction curve of boehmite.
The present invention providesThe flake-shaped crystal grain boehmite has proper length/width ratio and thinner lamella, and the gamma-Al prepared by roasting the flake-shaped crystal grain boehmite 2 O 3 The carrier has large specific surface area and pore volume, and the contents of strong acid and medium strong acid are high, more than 80%.
Drawings
FIG. 1 is a scanning electron micrograph of boehmite prepared according to example 1 of the present invention.
FIG. 2 is a scanning electron micrograph of boehmite prepared according to example 4 of the present invention.
FIG. 3 is a scanning electron micrograph of boehmite prepared according to example 7 of the invention.
FIG. 4 is a scanning electron micrograph of boehmite prepared according to example 9 of the present invention.
Detailed Description
The flaky grain boehmite provided by the invention has the advantages of thinner lamella, basically equivalent length and width, regular grain structure and uniform grain size. The boehmite is prepared by adding a grain structure regulating agent consisting of hydroxycarboxylic acid and monohydric alcohol into aluminum hydroxide slurry obtained by hydrolyzing alkoxy aluminum, aging the aluminum hydroxide slurry under the standing condition, and then drying. gamma-Al prepared by roasting boehmite 2 O 3 Has large specific surface area and large pore volume, and has high content of strong acid and medium strong acid, is excellent drying agent, adsorbent and catalyst carrier, and is especially suitable for being used as the carrier of naphtha reforming catalyst.
Crystal grains D of boehmite of the invention (200) 10 to 15nm, preferably 12.6 to 15nm, D (002) 14 to 26nm, preferably 14 to 20nm (020) 1.5 to 8nm, preferably 2 to 6nm.
According to the invention, D (200) Represents the grain size, D, measured along the (200) crystal plane in the XRD diffraction profile (002) Represents the grain size, D, measured along the (002) crystal plane in the XRD diffraction profile (020) Represents the grain size measured along the (020) crystal plane in the XRD diffraction curve. Preferably, D of the boehmite grains (200) /D (002) ＝0.7～1，D (020) /l＝0.2～0.5。
The grain sizes (D) in the boehmite X-ray diffraction curve in different diffraction directions were calculated from the Sherrer formula described in formula (1).
In the formula (1), D is the average value of the grain size in the normal direction of the crystal face of (HKL) and is unit nm; k is a constant, and can be approximately 0.89; lambda is the X-ray wavelength, and the characteristic wavelength of CuK alpha 1 is 0.154056nm; theta is a grazing angle corresponding to a diffraction peak of a (HKL) crystal face, also called a half-diffraction angle, and the unit is an angle; beta is the broadening amount of the diffraction peak caused by grain refinement, the unit is radian, and the relation between the broadening amount and the actually measured half-peak width B of the diffraction peak and the increasing width B of the diffraction peak caused by the instrument factors such as the absorption of the sample, the diaphragm size and the like is as follows:
in the formula (1), D may be a crystal grain size D measured along a (020) crystal plane in an XRD diffraction curve (020) Grain size D measured along the (200) crystal plane (200) Crystal grain size D measured along (002) crystal plane (002) 。
The preparation method of the boehmite comprises the steps of adding a crystal grain structure regulating agent into aluminum hydroxide slurry obtained after hydrolysis of alkoxy aluminum, standing and aging at 60-260 ℃ for 0.5-72 hours, and then drying, wherein the crystal grain structure regulating agent comprises hydroxycarboxylic acid and monohydric alcohol, the mass ratio of the hydroxycarboxylic acid to the monohydric alcohol is 0.3-7, the molar ratio of the hydroxycarboxylic acid to aluminum contained in the aluminum hydroxide slurry is 0.005-0.5, and the monohydric alcohol is C 2 ～C 8 A monohydric alcohol of (1).
In the above method, the hydrolysis temperature of the aluminum alkoxide is preferably 60 to 100 ℃, more preferably 75 to 95 ℃, the hydrolysis time is preferably 0.3 to 3 hours, more preferably 0.5 to 2 hours, and the molar ratio of water to the aluminum alkoxide is preferably 3 to 40, more preferably 6 to 30. The hydrolysis of the aluminum alkoxide is preferably carried out with stirring, preferably at a rate of from 100 to 300rpm, preferably from 110 to 250rpm.
The alkoxy aluminum is hydrolyzed to generate aluminum hydroxide and alcohol, water is always contained in the reaction system due to excessive water, and a two-phase system with an upper layer of alcohol phase and a lower layer of aluminum hydroxide slurry phase is generated after hydrolysis. Separating the upper alcohol phase, aging the obtained aluminum hydroxide slurry, adding a grain structure regulator in the aging process, and then drying to obtain the boehmite.
In the method, the aging of the aluminum hydroxide slurry is carried out under the standing condition, the aging temperature is preferably 100-220 ℃, and the aging time is preferably 2-24 hours.
The number of carbon atoms of the hydroxycarboxylic acid in the grain structure regulating agent is 3-5, the number of hydroxyl groups is 1-3, and the number of carboxyl groups is 1-3. Preferably, the hydroxycarboxylic acid is one or more of hydroxypropionic acid, 2-hydroxysuccinic acid, 2,3-dihydroxysuccinic acid and 3-hydroxy-1,3,5 pentanedioic acid.
The monohydric alcohol is preferably C 2 ～C 6 Preferably ethanol, propanol, isopropanol, butanol, pentanol or n-hexanol.
The mass ratio of the hydroxycarboxylic acid to the monohydric alcohol is preferably 0.5 to 5, and the molar ratio of the hydroxycarboxylic acid to aluminum contained in the aluminum hydroxide slurry is preferably 0.01 to 0.2. The hydroxycarboxylic acid may be a combination of two hydroxycarboxylic acids, in which case the mass ratio of the hydroxycarboxylic acid to the monohydric alcohol and the molar ratio of the hydroxycarboxylic acid to aluminum contained in the aluminum hydroxide slurry are based on the total amount of hydroxycarboxylic acids used.
The aluminum hydroxide slurry is dried after aging, and the drying temperature is preferably 100-240 ℃. The drying can be drying, spray drying or flash drying. When drying by baking is employed, the drying temperature is preferably 100 to 150 ℃ and the drying time is preferably 8 to 24 hours, more preferably 8 to 12 hours. When spray drying is adopted, the inlet temperature of the spray dryer is preferably 180-230 ℃, and the outlet temperature of the spray dryer is preferably 80-120 ℃. Flash drying is carried out by conventional methods by evaporating water by heating under reduced pressure.
In the above process, the aluminum alkoxide is prepared by reacting metallic aluminum with an excess amount of fatty alcohol, and preferably, may be prepared by a two-step addition method comprising the steps of:
(1) Adding aluminum and alcohol into a reaction kettle, initiating reaction at a reaction temperature of 5-50 ℃ lower than the boiling point of the alcohol until the reaction is stable,
(2) And adding alcohol into the reaction kettle, and continuing to react until the aluminum is completely dissolved.
The aluminum used for preparing the aluminum alkoxide in the above method may be at least one of aluminum wire, aluminum sheet, aluminum ingot, aluminum bean and aluminum powder, and the purity of the aluminum is not less than 99.7 mass%, preferably not less than 99.85 mass%. Preferably, the purity of the aluminum used for the initiation reaction in the step (1) is higher than that of the aluminum used for the preparation of the aluminum alkoxide in the step (2).
The alcohol may be C 3 ～C 12 Fatty alcohols of (2), preferably C 6 ～C 8 Such as n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, isopentanol, n-hexanol, isohexanol, n-heptanol, isoheptanol, n-octanol, and isooctanol. The purity of the alcohol is not less than 99.5 mass%, preferably not less than 99.8 mass%.
The alcohol is used in the step (1) in an amount of 5 to 40%, preferably 10 to 35%, based on the total amount of alcohol required for the whole reaction.
In the whole reaction of the method, the molar ratio of the alcohol to the aluminum is 3-10: 1. preferably 4 to 6:1.
in the above step (2), it is preferable to control the reaction temperature within. + -. 20 ℃ from the boiling point of the alcohol in order to make the reaction proceed smoothly.
The present invention is further illustrated by the following examples, but the present invention is not limited thereto.
In the examples, D of the grains of the boehmite sample (020) 、D (200) And D (002) Calculated by Sherrer formula according to the half-peak widths of diffraction peaks along the (020) crystal plane, the (200) crystal plane and the (002) crystal plane in the XRD diffraction curve of boehmite. The XRD diffraction profile was obtained using a Philips X' pert X-ray diffractometer using a Cu target, ka radiation, ni filtering, λ =0.154056nm. The voltage of the solid detector is 40kV, the current of the solid detector is 40mA, and the scanning range is 5-90 degrees.
The shape of the crystal grains of the boehmite is observed by an S-4800 type scanning electron microscope produced by Hitachi company, the accelerating voltage is 5.0kV, and the magnification is 1-300 k.
γ-Al 2 O 3 Is prepared from boehmite by calcining at 600 deg.C in air atmosphere for 3 hr.
γ-Al 2 O 3 The pore volume and the specific surface area of the catalyst are measured by a nitrogen adsorption and desorption method, and the method is GB/T5816-1995.
γ-Al 2 O 3 The surface acidity of the catalyst is desorbed by ammonia gas-temperature programming (NH) 3 -Temperature Programmed Desorption，NH 3 TPD), the used instrument is an Autochem II 2920 type automatic chemical adsorption instrument, and the specific steps are as follows: 0.1g of gamma-Al is weighed 2 O 3 Loading the particles into a sample tube, placing in a heating furnace, heating to 600 deg.C at 20 deg.C/min with He as carrier gas, purging for 60min to remove γ -Al 2 O 3 Surface adsorbed impurities; then cooling to 100 ℃, keeping the temperature for 10min, and switching the gas into NH 3 NH with a volume fraction of 10% 3 Adsorbing with mixed gas of/He for 30min, and purging with He for 90min to remove NH adsorbed by physical adsorption 3 (ii) a And (4) heating to 550 ℃ at the speed of 10 ℃/min for desorption, and monitoring and recording gas component change information by adopting a TCD (thermal conductivity detector). By subjecting the sample to NH 3 Calculating the total acid amount by integrating the peak areas of the TPD curves, and calculating the proportion of strong acid, medium acid and weak acid by adopting Gaussian fitting, wherein the peak generated at the desorption temperature of 100-260 ℃ is weak acid, the peak generated at 260-420 ℃ is medium acid, and the peak generated at 420-580 ℃ is strong acid.
Example 1
27 g of aluminum beans with the purity of 99.9 mass% are added into a three-neck flask with a reflux condenser, 90ml (0.7 mol) of n-hexanol with the purity of 99.8 mass% is added at the same time, the reaction is started after 20min of 130 ℃ reflux, 362ml (2.9 mol) of n-hexanol is continuously and slowly added into the three-neck flask, the temperature is maintained at 140 ℃, and the reflux reaction is carried out for 2hr, so that a mixture of n-hexyloxy aluminum and n-hexanol is obtained.
The mixture of n-hexyloxy aluminum and n-hexylalcohol is cooled to 90 ℃, 468g of deionized water is added into the mixture for hydrolysis at the stirring speed of 120rpm, the hydrolysis time is 45min, and the hydrolysis temperature is 90 ℃. Hydrolyzing to obtain the upper layerIs a two-phase system with an alcohol phase and a lower layer of an aluminum hydroxide slurry phase. Decanting to separate the upper aqueous n-hexanol phase, adding crystal grain structure regulator composed of 9g of 2-hydroxypropionic acid (lactic acid) and 14g of n-hexanol into the lower aluminum hydroxide slurry, transferring the aluminum hydroxide slurry into a stainless steel pressure kettle, standing at 120 deg.C for aging for 6hr, washing the aged slurry with deionized water, and drying in an oven at 120 deg.C for 12hr to obtain boehmite A. Calculation of D from its XRD diffraction Curve (020) 、D (200) And D (002) And l, D (200) /D (002) And D (020) The results are shown in Table 1. The scanning electron micrograph of boehmite A is shown in FIG. 1, which shows that the crystal grains are regular.
Calcining boehmite A at 600 deg.C under air atmosphere for 6hr to obtain gamma-Al 2 O 3 The specific surface area and pore volume of the carrier a are shown in Table 2, and the surface acid distribution is shown in Table 3.
Example 2
Boehmite was prepared according to the method of example 1 except that the grain structure modifier was composed of 9g of 3-hydroxypropionic acid and 9g of isopropyl alcohol, the aluminum hydroxide slurry to which the grain structure modifier was added was left to stand at 120 ℃ for aging for 6hr, and after aging, the slurry was washed with deionized water and then dried in an oven at 120 ℃ for 12hr to obtain boehmite B. It D (020) 、D (200) And D (002) And l, D (200) /D (002) And D (020) The/l is shown in Table 1.
Calcining boehmite B at 600 deg.C in air for 6hr to obtain gamma-Al 2 O 3 The specific surface area and pore volume of support b are shown in Table 2, and the surface acid distribution is shown in Table 3.
Example 3
Boehmite was prepared according to example 1 except that the grain structure modifier used consisted of 8g of 2-hydroxysuccinic acid (malic acid) and 5.4g of isopropanol, and the aluminum hydroxide slurry to which the grain structure modifier was added was aged and dried to give boehmite C, D of which (020) 、D (200) And D (002) And l, D (200) /D (002) And D (020) The/l is shown in Table 1.
Calcining boehmite C at 600 deg.C in air for 6hr to obtain gamma-Al 2 O 3 The specific surface area and pore volume of support c are shown in Table 2, and the surface acid distribution is shown in Table 3.
Example 4
Boehmite was prepared according to example 1 except that the grain structure modifier used consisted of 8g of 2-hydroxysuccinic acid (malic acid) and 8g of absolute ethanol, and the aluminum hydroxide slurry to which the grain structure modifier was added was aged and dried to give boehmite D, D of which (020) 、D (200) And D (002) And l, D (200) /D (002) And D (020) See Table 1 for,/l, and FIG. 2 for a scanning electron micrograph.
Calcining boehmite D at 600 deg.C in air for 6hr to obtain gamma-Al 2 O 3 The specific surface area and pore volume of support d are shown in Table 2, and the surface acid distribution is shown in Table 3.
Example 5
Boehmite was prepared as in example 1, except that the grain structure modifier used consisted of 12g of 2,3-dihydroxysuccinic acid (tartaric acid) and 3g of absolute ethanol, and the aluminum hydroxide slurry to which the grain structure modifier was added was aged and dried to give boehmite E, D thereof (020) 、D (200) And D (002) And l, D (200) /D (002) And D (020) The/l is shown in Table 1.
Calcining boehmite E at 600 deg.C in air for 6hr to obtain gamma-Al 2 O 3 The specific surface area and pore volume of support e are shown in Table 2, and the surface acid distribution is shown in Table 3.
Example 6
Boehmite was prepared according to example 1 except that the grain structure modifier used consisted of 12g of 2,3-dihydroxysuccinic acid (tartaric acid) and 8g of isopropanol, and the aluminum hydroxide slurry to which the grain structure modifier was added was aged and dried to give boehmite F, D, thereof (020) 、D (200) And D (002) And l, D (200) /D (002) And D (020) The/l is shown in Table 1.
Calcining boehmite F at 600 deg.C in air for 6hr,to obtain gamma-Al 2 O 3 The specific surface area and pore volume of the carrier f are shown in Table 2, and the surface acid distribution is shown in Table 3.
Example 7
Boehmite was prepared according to example 1 except that the grain structure modifier used consisted of 15.4G of 3-hydroxy-1,3,5 pentanedioic acid (citric acid) and 8G of isopropanol, and the aluminum hydroxide slurry to which the grain structure modifier was added was aged and dried to give boehmite G, D, thereof (020) 、D (200) And D (002) And l, D (200) /D (002) And D (020) See Table 1 for,/l, and FIG. 3 for a scanning electron micrograph.
Calcining boehmite G in air at 600 deg.C for 6hr to obtain gamma-Al 2 O 3 The specific surface area and pore volume of the support g are shown in Table 2, and the surface acid distribution is shown in Table 3.
Example 8
Boehmite was prepared according to the procedure of example 1, except that the grain structure modifier used consisted of 15.4g of 3-hydroxy-1,3,5 pentanetricacid (citric acid) and 5g of absolute ethanol, and the aluminum hydroxide slurry to which the grain structure modifier was added was aged and dried to give boehmite H, D, thereof (020) 、D (200) And D (002) And l, D (200) /D (002) And D (020) The/l is shown in Table 1.
Calcining boehmite H at 600 deg.C in air for 6hr to obtain gamma-Al 2 O 3 The specific surface area and pore volume of the carrier h are shown in Table 2, and the surface acid distribution is shown in Table 3.
Example 9
Boehmite was prepared according to example 1 except that the grain structure modifier used consisted of 4.5g of 2-hydroxypropionic acid (lactic acid), 4g of 2-hydroxysuccinic acid (malic acid) and 6.5g of absolute ethanol, and the aluminum hydroxide slurry to which the grain structure modifier was added was aged and dried to give boehmite I, D, of which (020) 、D (200) And D (002) And l, D (200) /D (002) And D (020) See Table 1 for,/l, and FIG. 4 for a scanning electron micrograph.
Calcining boehmite I at 600 deg.C in air for 6hr,to obtain gamma-Al 2 O 3 The specific surface area and pore volume of the carrier i are shown in Table 2, and the surface acid distribution is shown in Table 3.
Example 10
Boehmite was prepared according to example 1 except that the grain structure modifier used consisted of 4g of 2-hydroxysuccinic acid (malic acid), 6g of 2,3-dihydroxysuccinic acid (tartaric acid) and 10g of absolute ethanol, and the aluminum hydroxide slurry to which the grain structure modifier was added was aged and dried to give boehmite J, D of which (020) 、D (200) And D (002) And l, D (200) /D (002) And D (020) The/l is shown in Table 1.
Calcining boehmite J at 600 deg.C in air for 6hr to obtain gamma-Al 2 O 3 The specific surface area and pore volume of support j are shown in Table 2, and the surface acid distribution is shown in Table 3.
Comparative example 1
Boehmite was prepared according to example 1 except that, without adding a grain structure modifier to the aluminum hydroxide slurry, the aluminum hydroxide slurry was aged and dried to give boehmite M, D thereof (020) 、D (200) And D (002) And l, D (200) /D (002) And D (020) The/l is shown in Table 1.
Calcining boehmite M at 600 deg.C in air for 6hr to obtain gamma-Al 2 O 3 The specific surface area and pore volume of the carrier m are shown in Table 2, and the surface acid distribution is shown in Table 3.
Comparative example 2
Boehmite was prepared as in example 1, except that 15.2g xylitol (pentanol) was added as a grain structure modifier to the aluminum hydroxide slurry, which was aged and dried to give boehmite N, D thereof (020) 、D (200) And D (002) And l, D (200) /D (002) And D (020) The/l is shown in Table 1.
Calcining boehmite N at 600 deg.C in air for 6hr to obtain gamma-Al 2 O 3 The specific surface area and pore volume of the carrier n are shown in Table 2, and the surface acid distribution is shown in Table 3.
As can be seen from table 2, it is,Gamma-Al prepared from boehmite of the invention 2 O 3 Has larger specific surface area and pore volume. Table 3 shows the gamma-Al obtained according to the invention 2 O 3 The surface acid distribution of (2) has a high proportion of strong acid to medium strong acid, which accounts for about 80%, and a low proportion of weak acid, which are both below 24.1%.
TABLE 1
TABLE 2
| Example number | γ-Al 2 O 3 Numbering | Specific surface area, m 2 /g | Pore volume, cm 3 /g |
| 1 | a | 217 | 0.69 |
| 2 | b | 223 | 0.65 |
| 3 | c | 235 | 0.62 |
| 4 | d | 239 | 0.60 |
| 5 | e | 251 | 0.55 |
| 6 | f | 245 | 0.52 |
| 7 | g | 252 | 0.49 |
| 8 | h | 260 | 0.47 |
| 9 | i | 236 | 0.62 |
| 10 | j | 254 | 0.53 |
| Comparative example 1 | m | 263 | 0.32 |
| Comparative example 2 | n | 241 | 0.41 |
TABLE 3
Claims (12)
1. Flake-grain boehmite, D of crystal grain thereof (200) /D (002) ＝0.5～1.5，D (020) L = 0.05-0.6, wherein l =1/2[D (200) 2 +D (002) 2 ] 1/2 D is said to (020) 、D (200) And D (002) The crystal grain sizes calculated by the Sherrer formula are respectively based on the half-peak widths of diffraction peaks in the directions of the (020) crystal plane, (200) crystal plane and the (002) crystal plane in the X-ray diffraction curve of boehmite.
2. The boehmite according to claim 1 characterized in that D of said boehmite grains (200) /D (002) ＝0.7～1，D (020) /l＝0.2～0.5。
3. The boehmite according to claim 1 or 2, characterized in that D of the boehmite grains (200) Is 10 to 15nm (002) Is 14-26nm in size (020) Is 1.5-8 nm.
4. A process for preparing boehmite as claimed in claim 1, which includes such steps as adding the crystal grain structure regulator (hydroxy carboxylic acid and hydroxy carboxylic acid) to the aluminium hydroxide slurry obtained after hydrolysis of alkoxy aluminium, ageing at 60-260 deg.C for 0.5-72 hr, and dryingA monohydric alcohol, wherein the mass ratio of the hydroxycarboxylic acid to the monohydric alcohol is 0.3 to 7, the molar ratio of the hydroxycarboxylic acid to aluminum contained in the aluminum hydroxide slurry is 0.005 to 0.5, and the monohydric alcohol is C 2 ～C 8 A monohydric alcohol of (1).
5. The method according to claim 4, wherein the hydroxycarboxylic acid has 3 to 5 carbon atoms, 1 to 3 hydroxyl groups and 1 to 3 carboxyl groups.
6. The method of claim 5, wherein the hydroxycarboxylic acid is one or more of hydroxypropionic acid, 2-hydroxysuccinic acid, 2,3-dihydroxysuccinic acid, and 3-hydroxy-1,3,5 pentanedioic acid.
7. A method according to claim 4, wherein the monohydric alcohol is C 2 ～C 6 A monohydric alcohol of (1).
8. A process according to claim 4, characterized in that the aluminium hydroxide slurry is aged at a temperature of 100 to 220 ℃ for a time of 2 to 24 hours.
9. The method according to claim 4, wherein the drying temperature is 100 to 240 ℃, and the drying is oven drying, spray drying or flash drying.
10. The method according to claim 9, wherein the drying is carried out at a drying temperature of 100 to 150 ℃ for 8 to 24 hours.
11. A method according to claim 9, characterized in that when spray drying is used, the inlet temperature of the spray dryer is 180-230 ℃ and the outlet temperature is 80-120 ℃.
12. A process according to claim 4, wherein the aluminium alkoxide is hydrolysed at a temperature of 60 to 100 ℃ for a period of 0.3 to 3 hours and at a water to aluminium alkoxide molar ratio of 3 to 40.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910990737.5A CN112678853B (en) | 2019-10-18 | 2019-10-18 | Flaky grain boehmite and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910990737.5A CN112678853B (en) | 2019-10-18 | 2019-10-18 | Flaky grain boehmite and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112678853A CN112678853A (en) | 2021-04-20 |
| CN112678853B true CN112678853B (en) | 2023-04-18 |
Family
ID=75444706
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910990737.5A Active CN112678853B (en) | 2019-10-18 | 2019-10-18 | Flaky grain boehmite and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112678853B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023232021A1 (en) * | 2022-05-30 | 2023-12-07 | 中国石油化工股份有限公司 | Pseudo-boehmite and preparation method therefor, and catalytic cracking catalyst comprising pseudo-boehmite and preparation and use thereof |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3152865A (en) * | 1961-01-06 | 1964-10-13 | Engelhard Ind Inc | Process for producing a stable alumina monohydrate |
| JPS62226811A (en) * | 1986-03-27 | 1987-10-05 | Sumitomo Metal Mining Co Ltd | Production of alumina carrier |
| US5100641A (en) * | 1988-02-11 | 1992-03-31 | Vereinigte Aluminium-Werke Aktiengesellschaft | Method for the production of fillers and flame retardants based on gibbsite and application in plastics |
| JPH05279019A (en) * | 1992-03-30 | 1993-10-26 | Yoshida Kogyo Kk <Ykk> | Fine sheet-like boehmite particle and production therefor |
| JPH1121125A (en) * | 1997-07-01 | 1999-01-26 | Ykk Corp | Fine thin platy boehmite particles and their production |
| CN1919737A (en) * | 2005-08-26 | 2007-02-28 | 大连路明纳米材料有限公司 | Method of preparing good dispersion and high-purity ultra-fine alpha-Al2O3 |
| CN103601226A (en) * | 2013-12-02 | 2014-02-26 | 河津市远东特种铝业有限公司 | Preparation method for boehmite |
-
2019
- 2019-10-18 CN CN201910990737.5A patent/CN112678853B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3152865A (en) * | 1961-01-06 | 1964-10-13 | Engelhard Ind Inc | Process for producing a stable alumina monohydrate |
| JPS62226811A (en) * | 1986-03-27 | 1987-10-05 | Sumitomo Metal Mining Co Ltd | Production of alumina carrier |
| US5100641A (en) * | 1988-02-11 | 1992-03-31 | Vereinigte Aluminium-Werke Aktiengesellschaft | Method for the production of fillers and flame retardants based on gibbsite and application in plastics |
| JPH05279019A (en) * | 1992-03-30 | 1993-10-26 | Yoshida Kogyo Kk <Ykk> | Fine sheet-like boehmite particle and production therefor |
| JPH1121125A (en) * | 1997-07-01 | 1999-01-26 | Ykk Corp | Fine thin platy boehmite particles and their production |
| CN1919737A (en) * | 2005-08-26 | 2007-02-28 | 大连路明纳米材料有限公司 | Method of preparing good dispersion and high-purity ultra-fine alpha-Al2O3 |
| CN103601226A (en) * | 2013-12-02 | 2014-02-26 | 河津市远东特种铝业有限公司 | Preparation method for boehmite |
Non-Patent Citations (1)
| Title |
|---|
| 醇盐水解-水热法制备高结晶度纳米氢氧化铝;江琦等;《材料导报》;20081225;第22卷;第23-25页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112678853A (en) | 2021-04-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4814936B2 (en) | Boehmite having high surface area and method for producing γ-alumina | |
| CN112678856B (en) | Blocky crystal grain boehmite and preparation method thereof | |
| Sakr et al. | Mg-Zn-Al LDH: Influence of intercalated anions on CO2 removal from natural gas | |
| CN112678852B (en) | Flaky grain boehmite and preparation method thereof | |
| Ksapabutr et al. | Sol–gel derived porous ceria powders using cerium glycolate complex as precursor | |
| CN109675597B (en) | Preparation method of porous cobalt carbide | |
| CN112678853B (en) | Flaky grain boehmite and preparation method thereof | |
| CN111943242A (en) | Mesoporous gamma-Al2O3Preparation method of carrier and mesoporous gamma-Al2O3Carrier | |
| CN113860341B (en) | High-purity platy boehmite and preparation method thereof | |
| CN101104523B (en) | Method for preparing high specific surface area high thermal stability aluminum oxide | |
| CN106232230B (en) | Method for producing metal/metal oxide materials from nanostructured substrates and use thereof | |
| Liu et al. | Preparation of high purity spherical γ-alumina using a reduction-magnetic separation process | |
| CN112678855B (en) | Regular strip-shaped crystal grain boehmite and preparation method thereof | |
| CN110937620B (en) | Non-stoichiometric zinc-aluminum spinel and preparation method thereof | |
| Suriye et al. | Surface defect (Ti3+) controlling in the first step on the anatase TiO2 nanocrystal by using sol–gel technique | |
| CN110612157A (en) | Precipitated catalyst comprising zirconium oxide supported copper for ethyl acetate hydrogenation | |
| Baharudin et al. | Synthesis of raspberry-like structure zinc oxide nanoparticles via glycol-solvothermal, low-temperature solvothermal and coprecipitation methods | |
| Liu et al. | Fast synthesis of mesoporous γ-alumina assisted by a room temperature ionic liquid and its use as a support for the promotional catalytic performance of dibenzothiophene hydrodesulfurization | |
| CN111617772B (en) | Supported Ni-Ga-Pd catalyst and preparation method and application thereof | |
| CN106276994B (en) | The preparation method of flake nano gamma-alumina | |
| CN112516993B (en) | Preparation method of alumina carrier | |
| Ksapabutr et al. | Preparation of zirconia powders by sol–gel route of sodium glycozirconate complex | |
| CN105084397B (en) | Strip-shaped crystal grain boehmite preparation method | |
| CN111825112B (en) | Preparation method of flaky alumina | |
| Kim et al. | Synthesis of Flower-Like Mesoporous γ-AlOOH and γ-Al2O3 Nanoarchitectures via an Ionic Liquid-Assisted Hydrothermal Route |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |