Method for preparing 2-methoxyalkenes and metal-organic frameworks and methods for preparing the same

Abstract

The present application relates to the field of catalytic cracking reaction, and discloses a preparation method of 2-methoxy alkene and a metal organic framework material and a preparation method thereof.The preparation method of the 2-methoxy alkene comprises: making 2,2-dimethoxy alkane undergo a cracking reaction in the presence of a catalyst.The 2-methoxy propylene is prepared by the method, the catalytic activity is high, the reaction can be carried out at a relatively low temperature, and a fixed bed reaction can be adopted, the product separation is simple, the catalyst can be repeatedly used, the service life is long, the environmental pollution can be reduced, and the synthesis cost of the 2-methoxy propylene can be obviously reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalytic cracking reaction, in particular to a preparation method of 2-methoxy olefin and metal organic framework material and a preparation method thereof. BACKGROUND

[0002] 2-methoxy propylene is very active and unstable, which is difficult to be prepared in industry. However, 2-methoxy propylene is a very important synthetic raw material in many synthetic drugs, especially in the synthesis of clarithromycin, which is a key intermediate, and 2-methoxy propylene is also an important raw material for vitamins and carotenes.

[0003] In the early stage, 2-methoxy propylene was prepared by cracking 2,2-dimethoxypropane in liquid phase, mostly using alkanes as solvent and sulfonic acid as catalyst. However, this method was gradually eliminated due to the relatively cumbersome post-processing and the corrosion of large amounts of sulfonic acid to industrial equipment. In 2002, Yang Shumin et al. published in Fine Chemical Intermediates, 2002, 321: (20-21) that 2,2-dimethoxypropane was catalytically cracked at about 115℃ using diethylene glycol dimethyl ether as solvent, succinic anhydride, pyridine and benzoic acid as catalyst, with a yield of 80.6% and a product purity of 98%. This process reduced the use of diethylene glycol dimethyl ether and protected the environment. However, diethylene glycol dimethyl ether is expensive, toxic and highly soluble in water, which needs to be further improved. In 1998, Dietrich et al. published in Patent 5767325.1998-6-16 that ZSM-5 catalyst was used for catalytic cracking of 2,2-dimethoxypropane in gas phase, with a reaction temperature of 280-340℃ and a product yield of 83.3%. The activity of the catalyst before and after the reaction hardly decreased. The advantages of this synthesis process are easy recovery of the catalyst, and the disadvantages are the complex preparation of the catalyst. In 2005, Cui Wei et al. published a work that 2,2-dimethoxypropane was cracked in gas phase under the condition of acidic catalyst, with a reaction temperature of 180-190℃ and a 2-methoxy propylene yield of more than 85% after cooling at -10℃. However, the catalyst has poor acid stability. The use of solid catalysts can better meet the needs of industrialization, but the catalysts are prone to deactivation, which leads to the increase of cost.

[0004] At present, it is necessary to find an effective and heterogeneous catalytic system for the industrial preparation of 2-methoxy propylene, to control the acidity of the catalyst in the heterogeneous system, to realize the reaction under mild conditions (such as lower temperature), to ensure the yield and purity of the product, to easily separate the materials after the reaction, to recycle and reuse the catalyst, and to control the coking in the reaction process. SUMMARY

[0005] The present application aims to overcome the above-mentioned problems existing in the prior art, and provide a preparation method of 2-methoxy olefin and a metal organic framework material and a preparation method thereof. The method for preparing 2-methoxy olefin has high catalytic activity, the reaction can be carried out at a relatively low temperature, and the yield and purity of the product are high. The fixed bed reaction can be used, the product separation is simple, the catalyst can be repeatedly used and has a long service life, the environmental pollution can be reduced, and the synthesis cost of 2-methoxy olefin can be significantly reduced.

[0006] In order to achieve the above-mentioned purpose, the present application provides a preparation method of 2-methoxy olefin, which comprises: carrying out a cracking reaction on 2,2-dimethoxy alkane in the presence of a catalyst, wherein the catalyst is a metal organic framework material, the ligand of the metal organic framework material is provided by a substance with a structure as shown in formula (1), and the coordination metal M is selected from at least one of ⅡA, ⅢA, ⅡB, ⅣB, ⅥB and Ⅷ metal elements; in formula (1), M" includes H and metal elements, the metal elements are selected from at least one of ⅠA and ⅡA metal elements; R is selected from C6-C24 aromatic groups, Z is selected from C6-C18 aromatic groups, and n is 0, 1 or 2.

[0007]

[0008] The second aspect of the present application provides a metal organic framework material, which is the metal organic framework material as defined in the first aspect or the partially acidified product as described in the first aspect.

[0009] The third aspect of the present application provides a preparation method of a metal organic framework material, which is the preparation method of the partially acidified product as described in the first aspect.

[0010] When the 2-methoxy olefin is prepared by using the technical scheme provided by the present application, the catalytic activity is high, the reaction can be carried out at a relatively low temperature, and the yield and purity of the product are high. The fixed bed reaction can be used, the product and the catalyst are separated simply, the catalyst can be repeatedly used and has a long service life, the environmental pollution can be reduced, and the synthesis cost of 2-methoxy olefin can be significantly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 FIG. 1 is a thermogravimetric diagram of the metal organic framework material provided in Example 1 of the present application. DETAILED DESCRIPTION

[0012] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as the exact dimensions are not critical to the invention. Any numeric range recited is intended to include all values from the lower value to the upper value, inclusive of both values, and to sub-ranges falling within the specified range. In this context, individual numerical values can be combined to form new numeric ranges not expressly disclosed.

[0013] In a first aspect, the present application provides a method for preparing 2-methoxyalkene, comprising: cracking 2,2-dimethoxyalkane in the presence of a catalyst, wherein the catalyst is a metal-organic framework material, the ligand of the metal-organic framework material is provided by a substance with a structure as shown in formula (1) and the coordination metal M is selected from at least one of Group IIA, Group IIIA, Group IIB, Group IVB, Group VIIB and Group VIII metal elements; in formula (1), M" includes H and a metal element selected from at least one of Group IIA and Group IIIA metal elements; R is selected from C6-C24 aromatic groups, Z is selected from C6-C18 aromatic groups, and n is 0, 1 or 2.

[0014]

[0015] The inventors of the present application found in research that when the above method is used to prepare 2-methoxyalkene, the catalytic activity is high, the reaction can be carried out at a relatively low temperature, and the reaction can be carried out in a fixed bed, the product and yield and purity are relatively high, the separation of the product from the catalyst after the reaction is simple, the catalyst can be repeatedly used and has a long service life, environmental pollution can be reduced, and the synthesis cost of 2-methoxyalkene can be significantly reduced. When the catalyst specified in the present application is used to catalyze the synthesis of 2-methoxyalkene, the catalytic activity is much higher than that of the commonly used catalysts such as sulfonic acid, benzoic acid, ZSM-5 and acidic aluminum oxide, greatly improving the synthesis efficiency of 2-methoxyalkene. As a very important pharmaceutical intermediate, the improvement of the synthesis efficiency of 2-methoxyalkene can greatly reduce its synthesis cost, which is extremely important for the development of the pharmaceutical industry.

[0016] It can be understood that M" includes H and a metal element, which means that the catalyst contains both the structure of M" as H and the structure of M" as a metal element.

[0017] It can be understood that M" includes H and a metal element, which means that the catalyst contains both the structure of M" as H and the structure of M" as a metal element.

[0018] According to the present application, preferably, the metal-organic framework material has a structure as shown in formula (2):

[0019]

[0020] As mentioned above, it can be understood that the metal-organic framework material also has a structure in which the H in -SO3H in formula (2) is replaced by the above-mentioned optional metal.

[0021] According to the present application, preferably, the coordinated metal is selected from at least one of Co, Fe, Mg, Zn, Zr, Cr and Al.

[0022] According to the present application, preferably, the metal element in M" is selected from at least one of Li, Na, K, Cs, Ca and Mg.

[0023] According to the present application, preferably, R is selected from one of a benzene ring, a biphenyl group or a terphenyl group. It can be understood that the benzene ring, the biphenyl group or the terphenyl group mentioned herein refer to the corresponding groups. The terphenyl group can be a p-terphenyl group.

[0024] According to the present application, preferably, Z is selected from a benzene ring or a biphenyl group.

[0025] In the present application, there is no particular limitation on the specific connection mode of the -CO2M2 group and R. For example, when R is a benzene ring, the metal-organic framework material can have a mode as shown in formula (4). The two -CO2M2 groups can be at any position, such as para, meta and ortho (the dotted line in the formula also indicates that there is no limitation on the specific connection position of the -CO2M2 group and R). Preferably, when R is a benzene ring, the metal-organic framework material has a structure as shown in formula (5), more preferably has a structure as shown in formula (6) or formula (7).

[0026]

[0027] When R is a biphenyl group, the -CO2M2 groups can be located on the benzene rings at both ends, respectively, and can have a structure as shown in formula (8). The dotted line in the formula also indicates that there is no limitation on the specific connection position of the -CO2M2 group and the phenyl group on R. Preferably, when R is a biphenyl group, the metal-organic framework material has a structure as shown in formula (9), more preferably has a structure as shown in formula (10) or formula (11).

[0028]

[0029]

[0030] When R is a terphenyl group, the -CO2M2 group can also be located on the two end benzene rings, respectively, and can have a structure as shown in formula (12). As above, the dotted line in the formula also indicates that the specific connecting position of the -CO2M2 group with the phenyl group on the R group is not limited. However, preferably, when R is a terphenyl group, the metal-organic framework material has a structure as shown in formula (13), more preferably has a structure as shown in formula (14) or formula (15).

[0031]

[0032]

[0033] According to the present application, preferably, the average particle size of the metal-organic framework material is 0.3-20 μm, the specific surface area is 80-2000 m 2 / g, the pore volume is 0.4-5 ml / g, and the most probable pore diameter is 0.08-7 nm.

[0034] According to the present application, preferably, the average particle size of the metal-organic framework material is 0.8-18 μm, the specific surface area is 100-1750 m 2 / g, the pore volume is 0.5-3 ml / g, and the most probable pore diameter is 0.1-6 nm.

[0035] According to the present application, preferably, the average particle size of the metal-organic framework material is 1-15 μm, the specific surface area is 150-1715 (for example, can be 150, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1715 and any two of the above values form a range and values within the range) m 2 / g, the pore volume is 1.1-2.4 (for example, can be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8 and any two of the above values form a range and values within the range) ml / g, and the most probable pore diameter is 0.3-5 (for example, can be 0.3, 1, 2, 3, 4, 5 and any two of the above values form a range and values within the range) nm.

[0036] According to the present application, preferably, the molar ratio of the metal element and H in M" is (0.001-1000):1, more preferably (0.001-100):1, and most preferably (0.3-2):1. The catalyst is stable in structure, acidic, and the acidity of the catalyst can be adjusted by adjusting the molar ratio of the alkali metal element and H, so as to improve the activity and efficiency of the catalyst. The molar ratio of the alkali metal element and H (i.e. the ratio of the sulfonic acid metal salt group to the sulfonic acid group) can be determined by thermogravimetric method. In the thermogravimetric curve, the weight of the metal-organic framework material mainly appears three times of weight loss as the temperature increases. According to the functional groups and organic common sense, the first time is caused by the weight loss of the sulfonic acid group, the second time is caused by the sulfonic acid metal salt group, and the last time is the complete combustion of the organic framework.

[0037] The catalyst provided by the present application can generally exist stably. Among them, the catalyst has relatively stable sulfonic acid groups, and the framework structure can exist stably in water and organic solvents.

[0038] According to the present application, preferably, the preparation method of the catalyst comprises:

[0039] (1) performing a coordination reaction on a compound represented by formula (3) with a metal source to be coordinated in the presence of a first solvent and an organic acid;

[0040] (2) performing partial acidification on the product of the coordination reaction in the presence of an inorganic acid;

[0041] In formula (3), M' is selected from at least one of the IA and IIA metal elements, and is preferably at least one of Li, Na, K, Cs, Ca and Mg; the metal M in the metal source to be coordinated is selected from at least one of the IIA, IIIA, IIB, IVB, VIIB and VIII metal elements, and is preferably at least one of Co, Fe, Mg, Zn, Zr, Cr and Al.

[0042]

[0043] It can be understood that R, Z and n are the same as described above.

[0044] In the present application, "partial acidification" means that the metal M' is partially replaced by H, so that the finally obtained partially acidified product has a part of the position of M' as a metal element and a part as H.

[0045] According to the present application, preferably, in step (1), the coordination reaction is carried out under the following conditions: temperature is 80-200℃, preferably 90-150 (for example, 90, 100, 110, 120, 130, 140, 150 and any two of the above values form a range and values within the range) ℃; time is 5-30 h, preferably 10-24 (for example, 10, 12, 14, 16, 18, 20, 22, 24 and any two of the above values form a range and values within the range) h.

[0046] Preferably, in step (1), the molar ratio of the metal source to be coordinated, the compound represented by formula (3), the first solvent and the organic acid is (1-5): 1: (1-100): (0.1-20), preferably (2-4): 1: (2-80): (1-15).

[0047] According to the present application, preferably, the metal source to be coordinated is selected from one of Zn(NO3)2, Zn(acac)2, Al(NO3)3 and ZrCl4. The above-mentioned metal source to be coordinated can be used in the form of its hydrate, for example, Zn(NO3)2·8H2O can be used. Among them, Zn(acac)2 refers to zinc acetylacetone.

[0048] According to the present application, preferably, the first solvent is selected from at least one of N,N-dimethylformamide (DMF), dioxane and N-methyl pyrrolidone.

[0049] According to the present application, preferably, in step (1), the organic acid is selected from at least one of formic acid, acetic acid, phenylacetic acid and benzoic acid.

[0050] After the coordination reaction, the material can be centrifuged and suction filtered, and the solid obtained after suction filtration can be sequentially washed and dried. The centrifugation condition can be 3500-6000 rpm, and the time can be 10-80 min; in the washing, DMF can be used for washing 2-4 times first, and then methanol can be used for washing 2-4 times, and the amount of the washing agent used in the washing is not particularly limited. The drying temperature can be 100-130℃, and the time can be 2-10 h.

[0051] According to the present application, preferably, in step (2), the inorganic acid is selected from at least one of hydrochloric acid, sulfuric acid and nitric acid, more preferably hydrochloric acid. The solid product obtained in step (1) can be mixed with an aqueous acid solution, and the concentration of the acid in the aqueous acid solution can be 0.8-8 mol / L.

[0052] According to the present application, preferably, the amount of the inorganic acid used is 0.01-0.99 mol per mole of the compound represented by formula (3). In this way, partial acidification can be ensured.

[0053] After the partial acidification, the material obtained from the partial acidification can be filtered, and the obtained solid can be washed with water for 2-4 times. The amount of water used for washing is not particularly limited.

[0054] In the present application, the preparation of the compound of formula (3) is not particularly limited. For example, when R is a benzene ring, Z is a benzene ring, and n is 1, the preparation of the compound of formula (3) can include: performing a substitution reaction on terephthalic acid and p-chlorobenzenesulfonate in the presence of a second solvent and a metal halide. The molar ratio of terephthalic acid, p-chlorobenzenesulfonate and metal halide can be 1:(0.1-3):(0.01-0.8).

[0055] When R is a benzene ring and n is 0, the preparation of the compound of formula (3) can include: performing a substitution reaction on terephthalic acid and chlorosulfonate in the presence of a second solvent and a metal halide. The molar ratio of terephthalic acid, chlorosulfonate and metal halide can be 1:(0.7-1.4):(0.01-0.1).

[0056] When R is a biphenyl group, Z is a benzene ring, and n is 1, the preparation of the compound of formula (3) can include: performing a substitution reaction on 4,4'-biphenyldicarboxylic acid and p-chlorobenzenesulfonate in the presence of a second solvent and a metal halide. The molar ratio of terephthalic acid, p-chlorobenzenesulfonate and metal halide can be 1:(0.7-1.5):(0.01-0.2).

[0057] The metal halide described above can be selected from at least one of FeCl3, RuCl3 and AlCl3. The second solvent described above can be selected from dichloromethane, chlorobenzene, etc. The amount of the second solvent is not particularly limited, for example, the amount of the second solvent can be 10-200 ml relative to 1 g of terephthalic acid. The metal element in the p-chlorobenzenesulfonate and the chlorosulfonate is M'.

[0058] The conditions of the substitution reaction are not particularly limited, for example, the reaction can be carried out at a temperature of 30-100°C, preferably 40-60°C, for a time of 3-36h, preferably 5-24h.

[0059] After the substitution reaction is completed, the material after the substitution reaction can be sequentially filtered, washed and dried. The washing can be carried out with the same washing agent as the second solvent for 2-4 times, and then washed with methanol for 2-4 times; the drying temperature can be 80-120°C, and the time can be 2-8h.

[0060] According to the present application, preferably, the cracking reaction is performed by feeding a gas containing 2,2-dimethoxyalkane into a reactor loaded with a catalyst.

[0061] According to a preferred embodiment of the present application, the reactor is a fixed bed reactor. The catalyst is filled in the fixed bed reactor, and the gas is fed into the reactor to perform the reaction.

[0062] Preferably, the gas containing 2,2-dimethoxyalkane is fed in an amount such that the space velocity of 2,2-dimethoxyalkane is 1000-20000 ml / h.

[0063] Preferably, the gas containing 2,2-dimethoxyalkane is fed in an amount such that the space velocity of 2,2-dimethoxyalkane is 1000-20000 ml / h.

[0064] According to the present application, preferably, the cracking reaction is performed under conditions including a temperature of 30-200°C, preferably 50-150 (for example, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, and any two of the above values and values within the range form a range) °C.

[0065] Preferably, after the cracking reaction, the method further comprises subjecting the liquid phase obtained from the cracking reaction to rectification.

[0066] Preferably, the rectification is performed in a rectification column, and the rectification temperature is 30-80°C, preferably 50-60 (for example, 50, 52, 54, 56, 58, 60, and any two of the above values and values within the range form a range) °C.

[0067] In a second aspect, the present application provides a metal-organic framework material, which is the metal-organic framework material defined in the first aspect or the partially acidified product of the first aspect.

[0068] In a third aspect, the present application provides a method for preparing a metal-organic framework material, which is the method for preparing the partially acidified product of the first aspect.

[0069] The present application will be described in detail below through examples.

[0070] In the following examples, the average particle size is determined by Thermo Scientific TMApreo scanning electron microscope, specific surface area, pore volume, most probable pore diameter were determined by physical adsorption instrument Anton Paar QuantaTec. The molar ratio of alkali metal elements and H in M" in the catalyst was determined by the ratio of sulfonic acid metal salt group and sulfonate group, i.e. by thermogravimetric method: the weight of the material mainly appeared three times of weight loss as the temperature increased, the first time was caused by the weight loss of sulfonate, the second time was caused by the weight loss of sulfonic acid metal salt group. Taking the metal organic framework material prepared in Example 1 as an example, as shown in Figure 1 the weight loss near 450-530℃ was caused by sulfonate, and the weight loss near 530-600℃ was caused by sulfonic acid metal salt group.

[0071] In the following examples, the reaction tube length used in the cracking reaction (using a fixed bed reaction) was 1 meter, and the inner diameter was 1 centimeter.

[0072] In the following examples, the liquid phase obtained after the reaction was subjected to rectification (reduced pressure rectification at 50℃, 0.2atm), and 2-methoxypropene, methanol and 2,2-dimethoxypropane were separated, and each substance and the corresponding content were confirmed by GC.

[0073] In the following examples, the conversion rate of 2,2-dimethoxypropane was calculated as follows: 100%-the mass percentage of 2,2-dimethoxypropane in the liquid phase obtained by reaction;

[0074] The reaction selectivity was calculated as follows: the ratio of the sum of the amount of 2-methoxypropene and the amount of methanol in the liquid phase obtained by reaction to the conversion rate value of 2,2-dimethoxypropane.

[0075] Example 1

[0076] (1) Preparation of acidic metal organic framework material 1, the corresponding coordination metal M of this material is Zr, and M" is H and Na.

[0077] 0.34g of AlCl3, 8.3g of terephthalic acid, 10.70g of sodium p-chlorobenzenesulfonate and 500mL of dichloromethane were added to a reaction bottle, and substitution reaction was carried out at 50℃ for 24h, suction filtration was carried out, the solid was washed with 50mL of dichloromethane for three times, 50mL of methanol for three times, and dried at 100℃ for 2h to obtain a white powder (confirmed by NMR to be a compound represented by formula (3), wherein M' is Na).

[0078] Then, ZrCl4, the compound represented by formula (3) described above, DMF and phenylacetic acid were subjected to coordination reaction (sintering crystal) at a molar ratio of 2.5:1:40:10 at 120℃ for 24h, centrifuged at 4000rpm for 20min, then suction filtration was carried out, the solid was washed with 50mL of DMF for three times, 50mL of methanol for three times, and the solid was dried at 105℃ for 3h to obtain a white solid.

[0079] To the obtained white solid, 1 mol / L hydrochloric acid was added in an amount of 0.07 mol per mol of the compound represented by formula (3), and acidification was performed at 25°C for 2 h with stirring; the solid was extracted with 50 mL of water three times to obtain an acidified metal organic framework material (it was confirmed by XRD spectrum and electron microscope scanning that the same framework structure as in formula (7) was obtained, wherein Zr is a coordination metal), wherein the average particle size of the obtained metal organic framework material was 3 μm, the specific surface area was 675 m2 / g, the pore volume was 1.5 ml / g, and the most probable pore diameter was 1.7 nm. The ratio of sodium sulfonate to sulfonic acid in this catalyst was 1:1. 2 / g, pore volume was 1.5 ml / g, and most probable pore diameter was 1.7 nm. The ratio of sodium sulfonate to sulfonic acid in this catalyst was 1:1.

[0080] (2) Perform a cracking reaction: the acid metal organic framework material prepared in step (1) was loaded into a reaction tube with a loading length of 1 cm. A gas containing 2,2-dimethoxypropane (the carrier gas was nitrogen) was introduced in an amount such that the space velocity of 2,2-dimethoxypropane was 5000 ml / h, and the reaction temperature was 100°C. The reaction product was monitored by GC (gas chromatography), and after the reaction was stable for one hour, the mass content of 2-methoxypropene, methanol and 2,2-dimethoxypropane in the liquid phase of the reaction product was 68.1 wt%, 30.2 wt%, and 1.5 wt%, respectively, i.e., the reaction conversion rate reached 98.5%, and the selectivity was 99.7%. After 1000 hours of reaction, the content of 2-methoxypropene began to decrease, indicating that the reaction life of the above-mentioned catalyst was 1000 hours.

[0081] Example 2

[0082] (1) Preparation of acid metal organic framework material 1, wherein the coordination metal M of this material is Zn, and M" is H and Na.

[0083] Into a reaction bottle, 0.71 g of AICI3, 24.20 g of 4,4'-diphenyldicarboxylic acid, 21.40 g of sodium p-chlorobenzenesulfonate and 1000 mL of chlorobenzene were added, and a substitution reaction was performed at 50°C for 12 h. The obtained solid was washed with 100 mL of chlorobenzene three times, washed with 100 mL of methanol three times, and dried at 80°C for 5 h to obtain a white powder (it was confirmed by nuclear magnetic resonance detection that it was a compound represented by formula (3), wherein M' is Na).

[0084] Then, Zn(NO3)2·8H2O, the compound represented by formula (3), DMF and acetic acid were mixed in a molar ratio of 2.5:1:25:5, and a coordination reaction (sintering crystal) was performed at 100°C for 24 h. After centrifugation at 4000 rpm for 20 min, the solid was extracted with 50 mL of DMF three times, extracted with 50 mL of methanol three times, and then the solid was dried at 105°C for 5 h to obtain a white solid.

[0085] To the white solid, 6 mol / L hydrochloric acid was added in an amount of 0.07 mol per mol of the compound shown in formula (3), and acidification was carried out at 35°C for 5h under stirring; the solid was extracted by filtration and washed with 50 mL of water three times to obtain an acidified metal organic framework material (the same framework structure as in formula (11) was confirmed by XRD spectrum and scanning electron microscope, wherein Zn is a coordination metal). The average particle size of the obtained metal organic framework material was 5 μm, the specific surface area was 965 m 2 / g, the pore volume was 7.4 ml / g, and the most probable pore diameter was 4 nm. The molar ratio of sodium sulfonate to sulfonate in the catalyst was 1:1.

[0086] (2) Perform the cleavage reaction: the acidified metal organic framework material prepared in step (1) is loaded into a reaction tube with a loading length of 1 cm. The amount of 2,2-dimethoxypropane-containing gas (nitrogen as the carrier gas) is such that the space velocity of 2,2-dimethoxypropane is 4500 ml / h, and the reaction temperature is 120°C. The reaction product is monitored by GC (gas chromatography), and after 5 hours of stable reaction, the mass content of 2-methoxypropene, methanol and 2,2-dimethoxypropane in the reaction liquid phase is 67.7 wt%, 30.1 wt%, 2.1 wt%, i.e. the conversion rate is 97.9%, and the selectivity is 99.9%. After 2000 hours of reaction, the content of 2-methoxypropene begins to decrease, indicating that the reaction life of the above-mentioned catalyst can reach 2000 hours.

[0087] Example 3

[0088] (1) Preparation of acidified metal organic framework material 1, the coordination metal M corresponding to the material is Zn, and M" is H and Na.

[0089] Into the reaction bottle, 0.8 g of FeCl3, 16.6 g of terephthalic acid, 16.5 g of sodium chlorosulfonate and 1000 mL of dichloromethane were added, and substitution reaction was carried out at 50°C for 5h, the solid was extracted by filtration and washed with 100 mL of dichloromethane three times, 100 mL of methanol three times, and dried at 80°C for 8h to obtain a white powder (nuclear magnetic detection confirmed to be a compound shown in formula (3), wherein M' is Na).

[0090] Then, Zn(acac)2, the compound shown in formula (3) above, DMF and acetic acid were subjected to coordination reaction (sintering crystal) at a molar ratio of 2.5:1:40:6 at 95°C for 24h, centrifuged at 4000 rpm for 50 min, then extracted by filtration, the solid was washed with 50 mL of DMF three times, 50 mL of methanol three times, and the solid was dried at 105°C for 8h to obtain a white solid.

[0091] To the obtained white solid, 5 mol / L hydrochloric acid was added in an amount of 0.06 mol per mol of the compound shown in formula (3), and acidification was performed at 25°C for 3 h with stirring; the solid was extracted by filtration and washed with 50 mL of water three times to obtain an acidified metal organic framework material (it was confirmed by XRD and electron microscope pattern that the same framework structure as in formula (6) was obtained, wherein Zn is a coordinated metal). The average particle size of the obtained metal organic framework material was 2.5 μm, the specific surface area was 503 m 2 / g, the pore volume was 2.1 ml / g, and the most probable pore diameter was 1.2 nm. The molar ratio of sodium sulfonate to sulfonate in the catalyst was 0.5:1.

[0092] (2) Preparation of 2-methoxypropene: The acidified metal organic framework material prepared in step (1) was loaded into a reaction tube with a loading length of 1 cm. A gas containing 2,2-dimethoxypropane (the carrier gas was nitrogen) was introduced in an amount such that the space velocity of 2,2-dimethoxypropane was 3000 ml / h, and the reaction temperature was 100°C. The reaction product was monitored by GC (gas chromatography), and after the reaction was stable for 1 h, the mass content of 2-methoxypropene, methanol and 2,2-dimethoxypropane in the liquid phase of the reaction product was 68.4 wt%, 30.3 wt% and 0.5 wt%, respectively. That is, the conversion rate was 99.5%, and the selectivity was 99.2%. After 700 h of reaction, the content of 2-methoxypropene began to decrease, indicating that the reaction life of the above-mentioned catalyst was 700 h.

[0093] Example 4

[0094] (1) Preparation of acidified metal organic framework material 3, which corresponds to a coordinated metal M of Al, M" of H and Li.

[0095] To the reaction bottle, 1.04 g of RuCl3, 16.6 g of terephthalic acid, 19.64 g of lithium p-chlorobenzenesulfonate and 1000 mL of dichloromethane were added, and substitution reaction was performed at 50°C for 24 h. The solid was extracted by filtration and washed with 100 mL of dichloromethane three times, 100 mL of methanol three times, and dried at 80°C for 8 h to obtain a white powder (it was confirmed by NMR detection that it was a compound shown in formula (3), wherein M' is Li).

[0096] Then, Al(NO3)3, the compound shown in formula (3), dioxane and acetic acid were mixed in a molar ratio of 3:1:80:12, and coordination reaction (sintering crystal) was performed at 120°C for 24 h. After centrifugation at 6000 rpm for 12 min, the solid was extracted by filtration, washed with 50 mL of DMF three times, 50 mL of methanol three times, and the solid was dried at 105°C for 3 h to obtain a white solid.

[0097] To the white solid obtained in step (1), 5 mol / L hydrochloric acid was added in an amount of 0.07 mol per mole of the compound shown in formula (3), and acidification was carried out at 50°C for 1 h under stirring; the solid was extracted by 50 mL of water for three times to obtain an acidic metal organic framework material (the same framework structure as in formula (7) was confirmed by XRD spectrum and scanning electron microscope, wherein Al is a coordination metal). The average particle size of the obtained metal organic framework material was 5 μm, the specific surface area was 1203 m 2 / g, the pore volume was 2.4 ml / g, and the most probable pore diameter was 3.0 nm. The ratio of lithium sulfonate to sulfonate in the catalyst was 0.43:1.

[0098] (2) Perform the cracking reaction: the acidic metal organic framework material prepared in step (1) was loaded into a reaction tube with a loading length of 2 cm. The amount of 2,2-dimethoxypropane-containing gas (nitrogen as the carrier gas) was such that the space velocity of 2,2-dimethoxypropane was 6000 ml / h, and the reaction temperature was 110°C. The reaction product was monitored by GC, and after 1 h of stable reaction, the mass content of 2-methoxypropene, methanol and 2,2-dimethoxypropane in the liquid phase of the reaction product was 68.3 wt%, 30.4 wt%, and 0.7 wt%, i.e. the conversion rate was 99.3%, and the selectivity was 99.4%. After 900 h of reaction, the content of 2-methoxypropene began to decrease, indicating that the reaction life of the above-mentioned catalyst was 900 h.

[0099] Comparative Example 1

[0100] According to the method of step (2) in Example 4, except that the catalyst was an acidic ceramic filler (purchased from Inoceram, model number I11206). After 1 h of stable reaction, the mass content of 2-methoxypropene, methanol and 2,2-dimethoxypropane in the liquid phase of the reaction product was 35.9 wt%, 15.9 wt%, and 37.2 wt% by real-time monitoring by GC, i.e. the conversion rate was 62.8%, and the selectivity was 82.3%. The low selectivity and the absence of other by-products in the product indicated that the organic substances in the system were carbonized on the surface of the catalyst.

[0101] Comparative Example 2

[0102] According to the method of step (2) in Example 3, except that the catalyst was an acidic resin (purchased from Inoceram, model number S27899-500g). After 5 h of stable reaction, the mass content of 2-methoxypropene, methanol and 2,2-dimethoxypropane in the liquid phase of the reaction product was 44.7 wt%, 19.9 wt%, and 33.6 wt% by real-time monitoring by GC, i.e. the conversion rate was 66.4%, and the selectivity was 97.3%.

[0103] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including that each technical feature is combined in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A process for the preparation of a 2-methoxy alkene, characterized in that, The method comprises: subjecting 2,2-dimethoxyalkane to a cracking reaction in the presence of a catalyst, wherein the catalyst is a metal-organic framework material, ligands of the metal-organic framework material are provided by a substance with a structure as shown in formula (1), and a coordination metal M is selected from at least one of Zn, Zr, Cr and Al; in formula (1), M" is H and a metal element selected from at least one of Li, Na and K; R is selected from a benzene ring or a biphenyl group, Z is selected from a benzene ring, and n is 0 or 1; （1）； The metal-organic framework material has a structure as shown in formula (2): （2）。 2. The method of claim 1, wherein, The metal organic framework material has an average particle size of 0.3-20 μm, a specific surface area of 80-2000 m 2 / g, a pore volume of 0.4-5 ml / g, and a most probable pore diameter of 0.08-7 nm.

3. The method of claim 2, wherein, The metal organic framework material has an average particle size of 0.8-18 μm, a specific surface area of 100-1750 m 2 / g, a pore volume of 0.5-3 ml / g, and a most probable pore diameter of 0.1-6 nm.

4. The method of claim 2, wherein, The metal organic framework material has an average particle size of 1-15 μm, a specific surface area of 150-1715 m 2 / g, a pore volume of 1.1-2.4 ml / g, and a most probable pore diameter of 0.3-5 nm.

5. The method of claim 1 or 2, wherein, In M", the molar ratio of the metal element to H is (0.001-1000):

1.

6. The method of claim 5, wherein, In M", the molar ratio of the metal element to H is (0.001-100):

1.

7. The method of claim 6, wherein, In M", the molar ratio of the metal element to H is (0.3-2):

1.

8. The method of claim 1, wherein, The preparation method of the catalyst comprises: (1) subjecting a compound shown in formula (3) to a coordination reaction with a metal source to be coordinated in the presence of a first solvent and an organic acid; (2) subjecting the product of the coordination reaction to partial acidification in the presence of an inorganic acid; In formula (3), M' is selected from at least one of Li, Na and K; and the metal M in the metal source to be coordinated is selected from at least one of Zn, Zr, Cr and Al; （3）。 9. The method of claim 8, wherein, In step (1), the coordination reaction is performed under conditions including: a temperature of 80-200 ℃; and a time of 5-30 h; And / or, in step (1), the molar ratio of the metal source to be coordinated, the compound shown in formula (3), the first solvent and the organic acid is (1-5): 1: (1-100): (0.1-20); And / or, the metal source to be coordinated is selected from one of Zn(NO3)2, Zn(acac)2, Al(NO3)3 and ZrCl4; And / or, the first solvent is selected from at least one of N,N-dimethylformamide, dioxane and N-methylpyrrolidone; And / or, in step (1), the organic acid is selected from at least one of formic acid, acetic acid, phenylacetic acid and benzoic acid.

10. The method of claim 9, wherein, In step (1), the coordination reaction is performed under conditions including: a temperature of 90-150 ℃; and a time of 10-24 h; And / or, in step (1), the molar ratio of the metal source to be coordinated, the compound shown in formula (3), the first solvent and the organic acid is (2-4): 1: (2-80): (1-15).

11. The method of claim 8, wherein, In step (2), the inorganic acid is selected from at least one of hydrochloric acid, sulfuric acid and nitric acid; And / or, the conditions of the partial acidification include: a temperature of 15-60 ℃, and a time of 1-10 h; And / or, the amount of the inorganic acid is 0.01-0.99 mol per mole of the compound shown in formula (3).

12. The method of claim 11, wherein, In step (2), the inorganic acid is hydrochloric acid.

13. The method of claim 1, wherein, The cracking reaction is performed by passing a gas containing 2,2-dimethoxyalkane into a reactor loaded with the catalyst.

14. The method of claim 13, wherein, The amount of the gas containing 2,2-dimethoxyalkane is such that the space velocity of 2,2-dimethoxyalkane is 1000-20000 ml / h.

15. The method of claim 14, wherein, The gas containing 2,2-dimethoxyalkane is carried by a non-reactive gas selected from at least one of nitrogen, helium and argon.

16. The method of claim 1 or 8, wherein, The conditions of the cleavage reaction include a temperature of 30-200°C. And / or, after the cleavage reaction, the method further includes: subjecting the liquid phase obtained from the cleavage reaction to rectification.

17. The method of claim 1 or 8, wherein, The conditions of the cleavage reaction include a temperature of 50-150°C.

18. The method of claim 16, wherein, The rectification is performed in a rectification column, and the rectification temperature is 30-80°C.

19. The method of claim 18, wherein, The rectification is performed in a rectification column, and the rectification temperature is 50-60°C.

Images