A supported catalyst, its preparation method and application in the catalytic preparation of glycine from glycolic acid

Abstract

The application discloses a supported catalyst, a preparation method thereof, and an application thereof in catalyzing the preparation of glycine from glycolic acid. The supported catalyst comprises a carrier and a hydrogenation metal supported on the carrier; the carrier is an MCM-41 molecular sieve doped with a metal; the hydrogenation metal is selected from at least one of Ru, Pd, Pt, Rh, Ni, Co, and Cu. The method has a high product yield, the catalyst is easy to separate, and has good stability. The method and the catalyst have broad application prospects when used.

Description

Technical Field

[0001] The present application relates to a supported catalyst, a preparation method thereof, and an application thereof in the catalytic preparation of glycine from glycolic acid, belonging to the technical field of chemical synthesis. Background Art

[0002] Glycine, also known as aminoacetic acid, is a white crystal or crystalline powder, odorless and non-toxic. It is an important fine chemical synthesis intermediate and is widely used in fields such as medicine, food, pesticides, and feed additives. With the improvement of people's living standards, the food and pharmaceutical industries have gradually become the largest fields using glycine, and its market demand is very large. The traditional domestic glycine synthesis process is the chloroacetic acid ammonolysis method, which is prepared by reacting chloroacetic acid with ammonia water in the presence of hexamine catalyst. This method has a simple production process and low cost, but the by-products in the production process cannot be removed, and the purity is relatively low. At the same time, hexamine cannot be recycled, resulting in waste of resources (Chinese invention application document CN113185420A). Other production methods of glycine, such as the Strecker method using highly toxic reagents and the biosynthetic method having strict requirements for the operating environment. Therefore, there is an urgent need to develop a highly selective, environmentally friendly and stable glycine preparation process. Summary of the Invention

[0003] The present invention aims to develop a highly efficient heterogeneous catalyst to reduce the hydroxyl group in glycolic acid by reductive amination to obtain an amino group and prepare glycine. Glycolic acid, also known as hydroxyacetic acid, is an important organic chemical raw material. Glycolic acid can be obtained by hydrolyzing cellulose, reverse aldol condensation, selective oxidation, or by hydrogenolysis of cellulose, selective oxidation, or by selective hydrogenation of dimethyl oxalate.

[0004] According to one aspect of the present application, a method for preparing glycine from glycolic acid is provided. This method has a high product yield and a simple process. This method uses hydrogen as a hydrogen source to prepare glycine by reductive amination of glycolic acid. The catalyst carrier used in this method is a metal-doped MCM-41 molecular sieve, which is beneficial to the formation of amino groups, realizes high selectivity for glycine, and has broad application prospects.

[0005] One aspect of the present application provides a supported catalyst. The supported catalyst includes a carrier and a hydrogenation metal supported on the carrier;

[0006] The carrier is a metal-doped MCM-41 molecular sieve;

[0007] The hydrogenation metal is selected from one of noble metals and non-noble metals;

[0008] The hydrogenation metal is selected from at least one of Ru, Pd, Pt, Rh, Ni, Co, and Cu;

[0009] Optionally, the doped metal is selected from at least one of Li, Na, K, Cs, Mg, Ca, Ba, Sr, Mn, Al, Zr, Ce, and Fe.

[0010] Optionally, in the supported catalyst, the loading amount of the hydrogenation metal is 0.2 to 30 wt%, wherein the mass of the supported catalyst is based on the mass of the carrier, and the mass of the hydrogenation metal is based on the mass of the hydrogenation metal element;

[0011] Optionally, in the supported catalyst, the loading amount of the hydrogenation metal is 2 to 20 wt%;

[0012] Optionally, in the supported catalyst, the loading amount of the hydrogenation metal is 2 to 10 wt%.

[0013] Optionally, the upper limit of the loading amount of the hydrogenation metal in the catalyst can be independently selected from 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 8 wt%, 10 wt%, 12 wt%, 20 wt%, 25 wt%, 30 wt%; the lower limit can be independently selected from 0.2 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 8 wt%, 10 wt%, 12 wt%, 20 wt%, 25 wt%.

[0014] Optionally, in the carrier, the doping amount of the doped metal is 1 to 20 wt%, wherein the mass of the doped metal is based on the mass of the doped metal element.

[0015] Optionally, the upper limit of the doping amount of the doped metal in the carrier can be independently selected from 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%; the lower limit can be independently selected from 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%.

[0016] In another aspect of the present application, a method for preparing the above-mentioned supported catalyst is provided, and the preparation method includes:

[0017] (1) Mixing a surfactant, a silicon source, an alkaline substance and water, aging, hydrothermally treating, and filtering to obtain a precipitate;

[0018] (2) Placing the precipitate obtained in step (1) into an organic solution containing an inorganic salt of a doped metal and refluxing, and calcining to obtain the carrier material A;

[0019] (3) Impregnating the carrier into a solution containing a hydrogenation metal precursor to obtain the supported catalyst.

[0020] As a specific implementation method, the catalyst is prepared by the following method:

[0021] A surfactant, a silicon source, an alkaline substance, and deionized water are mixed and aged. After hydrothermal treatment, filtration, and drying at room temperature, the obtained substance is refluxed in an organic solution of an inorganic salt doped with a metal, and calcined in a muffle furnace to obtain a support. The support is impregnated into a solution containing a hydrogenation metal precursor to obtain the catalyst, wherein the support is a metal-doped MCM-41 molecular sieve.

[0022] Optionally, the surfactant is selected from at least one of cetyltrimethylammonium bromide and cetyltrimethylammonium chloride;

[0023] Optionally, the silicon source is selected from at least one of methyl orthosilicate, ethyl orthosilicate, butyl orthosilicate, and sodium silicate;

[0024] Optionally, the alkaline substance is selected from at least one of ammonia water, ammonium carbonate, and sodium bicarbonate;

[0025] Optionally, the inorganic salt doped with a metal is selected from at least one of nitrates and chlorides;

[0026] Optionally, the organic solution containing the inorganic salt doped with a metal further includes an organic solvent;

[0027] The organic solvent is selected from at least one of methanol, ethanol, ether, and acetonitrile;

[0028] Optionally, the hydrogenation precursor is a compound containing a hydrogenation metal, and the compound containing a hydrogenation metal is selected from at least one of ruthenium trichloride, rhodium nitrate, palladium chloride, chloroplatinic acid, nickel nitrate, cobalt chloride, and copper nitrate;

[0029] Optionally, step (3) specifically includes the following steps:

[0030] The support (metal-doped MCM-41 molecular sieve) is impregnated into a solution containing a hydrogenation metal precursor, and the catalyst is obtained through stirring, standing, drying, and reduction.

[0031] Optionally, the solvent in the solution containing the hydrogenation metal precursor is water, and the amount of water is the saturated water absorption of the support.

[0032] Optionally, the specific conditions for the stirring include:

[0033] The stirring speed is 250 to 1200 rpm, preferably 400 to 800 rpm;

[0034] The stirring time is 0.5 to 12 h, preferably 0.5 to 6 h, and most preferably 0.5 to 2 h;

[0035] The standing time for the standing is 6 to 96 h, preferably 6 to 48 h, and most preferably 12 to 24 h.

[0036] Optionally, the upper limit of the stirring speed can be independently selected from 300 rpm, 400 rpm, 500 rpm, 600 rpm, 650 rpm, 700 rpm, 800 rpm, 850 rpm, 900 rpm, 1000 rpm, 1100 rpm, 1200 rpm; the lower limit can be independently selected from 250 rpm, 300 rpm, 400 rpm, 500 rpm, 600 rpm, 650 rpm, 700 rpm, 800 rpm, 850 rpm, 900 rpm, 1000 rpm, 1100 rpm.

[0037] Optionally, the upper limit of the stirring time can be independently selected from 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h; the lower limit can be independently selected from 0.5 h, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h.

[0038] Optionally, the upper limit of the standing time can be independently selected from 12 h, 18 h, 24 h, 28 h, 30 h, 32 h, 36 h, 42 h, 48 h, 54 h, 72 h, 96 h; the lower limit can be independently selected from 6 h, 12 h, 18 h, 24 h, 28 h, 30 h, 32 h, 36 h, 42 h, 48 h, 54 h, 72 h.

[0039] Optionally, the specific conditions for the drying include:

[0040] The drying temperature is 100 to 180 °C, preferably 110 to 120 °C; the drying time is 5 to 15 h, preferably 10 to 12 h.

[0041] Optionally, the upper limit of the drying temperature can be independently selected from 110 °C, 115 °C, 120 °C, 125 °C, 130 °C, 135 °C, 140 °C, 145 °C, 150 °C, 160 °C, 170 °C, 180 °C; the lower limit can be independently selected from 100 °C, 110 °C, 115 °C, 120 °C, 125 °C, 130 °C, 135 °C, 140 °C, 145 °C, 150 °C, 160 °C, 170 °C.

[0042] Optionally, the upper limit of the drying time can be independently selected from 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h; the lower limit can be independently selected from 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h.

[0043] Optionally, the specific conditions for reduction include:

[0044] Reduction is carried out in a hydrogen atmosphere;

[0045] The reduction temperature is 200 - 600 °C, preferably 250 - 500 °C; the reduction time is 1 - 8 h, preferably 2 - 4 h.

[0046] Optionally, the upper limit of the reduction temperature can be independently selected from 220 °C, 250 °C, 280 °C, 300 °C, 320 °C, 350 °C, 400 °C, 450 °C, 480 °C, 500 °C, 550 °C, 600 °C; the lower limit can be independently selected from 200 °C, 220 °C, 250 °C, 280 °C, 300 °C, 320 °C, 350 °C, 400 °C, 450 °C, 480 °C, 500 °C, 550 °C.

[0047] Optionally, the upper limit of the reduction time can be independently selected from 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h; the lower limit can be independently selected from 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h.

[0048] Optionally, the mass ratio of the surfactant to the silicon source is 0.1 - 0.8;

[0049] Optionally, the upper limit of the mass ratio of the surfactant to the silicon source can be independently selected from 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8; the lower limit can be independently selected from 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7.

[0050] Optionally, the alkaline substance adjusts the pH of the mixed solution to 10.5 - 11.5;

[0051] Optionally, the upper limit of the pH of the mixed solution adjusted by the alkaline substance can be independently selected from 10.8, 11.0, 11.2, 11.5; the lower limit can be independently selected from 10.5, 10.8, 11.0, 11.2.

[0052] Optionally, the mass ratio of water to the silicon source is 8 - 15;

[0053] Optionally, the upper limit of the mass ratio of water to the silicon source can be independently selected from 9, 10, 11, 12, 13, 14, 15; the lower limit can be independently selected from 8, 9, 10, 11, 12, 13, 14.

[0054] Wherein, the surfactant is based on the weight of the surfactant itself, the ammonia water is based on the weight of the ammonia water itself, the water is based on the weight of the water itself, and the silicon source is based on the weight of the silicon source itself.

[0055] Optionally, in the organic solution containing the inorganic salt doped with a metal, the concentration of the inorganic salt doped with a metal is 0.01 to 0.1 mol / L, and the molar amount of the inorganic salt doped with a metal is based on the molar amount of the doped metal element;

[0056] Optionally, the upper limit of the concentration of the organic solution of the inorganic salt doped with a metal can be independently selected from 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, 0.1 mol / L; the lower limit can be independently selected from 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, 0.09 mol / L.

[0057] Optionally, the mass ratio of the inorganic salt doped with a metal to Substance A is 0.1 to 1.5, and the mass of the inorganic salt doped with a metal is based on its own weight.

[0058] Optionally, the upper limit of the mass ratio of the inorganic salt doped with a metal to the substance A obtained after hydrothermal treatment can be independently selected from 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5; the lower limit can be independently selected from 0.1, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4

[0059] Optionally, the aging temperature is 25 to 80 °C, and the aging time is 10 to 48 h;

[0060] Optionally, the aging temperature is 30 to 50 °C, and the aging time is 12 to 36 h;

[0061] Optionally, the aging time is 18 to 24 h.

[0062] Optionally, the upper limit of the aging temperature can be independently selected from 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C; the lower limit can be independently selected from 25 °C, 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C.

[0063] Optionally, the upper limit of the aging time can be independently selected from 12 h, 14 h, 16 h, 18 h, 20 h, 24 h, 26 h, 30 h, 32 h, 36 h, 42 h, 48 h; the lower limit can be independently selected from 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 24 h, 26 h, 30 h, 32 h, 36 h, 42 h.

[0064] Optionally, the hydrothermal temperature is 120 - 200 °C, and the hydrothermal time is 12 - 96 h;

[0065] Optionally, the hydrothermal temperature is 120 - 180 °C, and the hydrothermal time is 12 - 48 h;

[0066] Optionally, the hydrothermal time is 15 - 24 h.

[0067] Optionally, the upper limit of the hydrothermal temperature can be independently selected from 130 °C, 140 °C, 150 °C, 155 °C, 160 °C, 165 °C, 170 °C, 175 °C, 180 °C, 185 °C, 190 °C, 200 °C; the lower limit can be independently selected from 120 °C, 130 °C, 140 °C, 150 °C, 155 °C, 160 °C, 165 °C, 170 °C, 175 °C, 180 °C, 185 °C, 190 °C

[0068] Optionally, the upper limit of the hydrothermal time can be independently selected from 15 h, 16 h, 18 h, 22 h, 24 h, 30 h, 36 h, 42 h, 48 h, 52 h, 72 h, 96 h; the lower limit can be independently selected from 12 h, 15 h, 16 h, 18 h, 22 h, 24 h, 30 h, 36 h, 42 h, 48 h, 52 h, 72 h.

[0069] Optionally, the reflux temperature is 45 - 100 °C, and the reflux time is 0.5 - 10 h;

[0070] Optionally, the reflux temperature is 80 - 90 °C, and the reflux time is 1 - 8 h;

[0071] Optionally, the reflux time is 2 - 4 h

[0072] Optionally, the upper limit of the reflux temperature can be independently selected from 50 °C, 55 °C, 60 °C, 70 °C, 80 °C, 85 °C, 90 °C, 100 °C; the lower limit can be independently selected from 45 °C, 50 °C, 55 °C, 60 °C, 70 °C, 80 °C, 85 °C, 90 °C.

[0073] Optionally, the upper limit of the reflux time can be independently selected from 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h; the lower limit can be independently selected from 0.5 h, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h.

[0074] Optionally, the calcination temperature is 450 - 650 °C; the calcination time is 3 - 10 h.

[0075] Optionally, the calcination temperature is 500 - 550 °C, and the calcination time is 3 - 8 h;

[0076] Optionally, the calcination time is 5 to 6 h.

[0077] Optionally, the upper limit of the calcination temperature can be independently selected from 500 °C, 520 °C, 550 °C, 580 °C, 600 °C, 650 °C; and the lower limit can be independently selected from 450 °C, 500 °C, 520 °C, 550 °C, 580 °C, 600 °C.

[0078] Optionally, the upper limit of the calcination time is selected from 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h; and the lower limit is selected from 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h.

[0079] In another aspect of the present application, a method for catalyzing the preparation of glycine from glycolic acid, the method comprising:

[0080] Introducing hydrogen into a mixed solution containing glycolic acid, a catalyst, and ammonia water for reductive amination reaction to obtain glycine;

[0081] Wherein the catalyst is selected from the above-mentioned supported catalyst or the supported catalyst obtained according to the above-mentioned preparation method.

[0082] Optionally, the molar amount of the catalyst is 0.1 to 40% of the molar amount of glycolic acid, wherein the molar amount of the catalyst is based on the molar amount of the hydrogenation metal element;

[0083] Optionally, the upper limit of the percentage of the molar amount of the catalyst to the molar amount of glycolic acid can be independently selected from 0.8%, 1.0%, 2%, 3%, 4%, 5%, 8%, 10%, 20%, 25%, 30%, 40%; and the lower limit can be independently selected from 0.1%, 0.8%, 1.0%, 2%, 3%, 4%, 5%, 8%, 10%, 20%, 25%, 30%.

[0084] Optionally, the specific conditions of the reductive amination reaction include:

[0085] The hydrogen partial pressure is 1.0 to 4.0 MPa;

[0086] The reaction temperature is 150 to 260 °C;

[0087] The reaction time is 2 to 48 h.

[0088] Optionally, the specific conditions of the reductive amination reaction include:

[0089] The hydrogen source partial pressure is 1.0 to 2.0 MPa;

[0090] The reaction temperature is 200 to 240 °C;

[0091] The reaction time is 4 to 12 h.

[0092] Optionally, the upper limit of the hydrogen partial pressure can be independently selected from 1.5 MPa, 2.0 MPa, 2.5 MPa, 3.0 MPa, 3.5 MPa, 4.0 MPa; the lower limit can be independently selected from 1.0 MPa, 1.5 MPa, 2.0 MPa, 2.5 MPa, 3.0 MPa, 3.5 MPa.

[0093] Optionally, the upper limit of the reaction temperature can be independently selected from 170 °C, 180 °C, 190 °C, 200 °C, 210 °C, 220 °C, 225 °C, 230 °C, 240 °C, 245 °C, 250 °C, 260 °C; the lower limit can be independently selected from 150 °C, 170 °C, 180 °C, 190 °C, 200 °C, 210 °C, 220 °C, 225 °C, 230 °C, 240 °C, 245 °C, 250 °C.

[0094] Optionally, the upper limit of the reaction time is selected from 4 h, 5 h, 6 h, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, 24 h, 36 h, 48 h; the lower limit is selected from 2 h, 4 h, 5 h, 6 h, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, 24 h, 36 h.

[0095] As a specific embodiment, glycolic acid, a catalyst, and ammonia water are added to a reaction kettle, mixed, heated to 150 - 260 °C, the hydrogen partial pressure is 1.0 - 4.0 MPa, and the reaction time is 2 - 48 h, and glycolic acid is reductively aminated to glycine.

[0096] In a specific embodiment, the present invention provides a preparation method of a reductive amination catalyst and its application in the highly selective preparation of glycine from glycolic acid. In this method, a surfactant, a silicon source, an alkaline substance, and deionized water are mixed and aged, then hydrothermally treated, filtered, dried at room temperature, and then the obtained substance is refluxed in a metal salt organic solution and calcined in a muffle furnace to obtain a support. The support is impregnated into a solution containing a hydrogenation metal precursor to obtain the catalyst, wherein the support is a metal-doped MCM-41 molecular sieve. This method has a high product yield, the catalyst is easy to separate, and has good stability. The method and the catalyst have broad application prospects when used.

[0097] The glycine product obtained by this catalyst has a high yield, the catalyst preparation method is simple, it is easy to separate from the system, and it can still maintain a high catalytic activity after being recycled multiple times.

[0098] The beneficial effects that this application can produce include:

[0099] 1) For the method for the reductive amination of glycolic acid to prepare glycine provided by the present invention, due to the metal doping effect in the catalyst support, high selectivity for glycine can be achieved.

[0100] 2) The catalyst system used in this method has good stability, high product yield and selectivity, low dosage, simple preparation process, and the catalyst is easy to separate from the system, being environmentally friendly.

[0101] 3) After the catalyst in this application is recycled five times, it can still maintain good stability, and the product yield remains above 45%. Specific Embodiments

[0102] The following describes this application in detail with reference to the embodiments, but this application is not limited to these embodiments.

[0103] Unless otherwise specified, the raw materials in the embodiments of this application are all purchased through commercial channels.

[0104] In the embodiments of this application, the conversion rate and yield are calculated as follows:

[0105]

[0106]

[0107] Example 1

[0108] (1) 5 g of tetraethyl orthosilicate, a surfactant, ammonia water, and deionized water were mixed evenly, where: the surfactant was cetyltrimethylammonium bromide, the mass ratio of the surfactant to the mass of tetraethyl orthosilicate was 0.3, the ammonia water adjusted the pH of the mixed solution to 11.0, and the mass ratio of deionized water to the mass of tetraethyl orthosilicate was 13; after the obtained mixed solution was aged at 50 °C for 24 h, it was hydrothermally treated at 180 °C for 24 h, filtered and dried at room temperature to obtain a dried product;

[0109] (2) The dried product obtained in step (1) was put into a methanol solution of zirconium nitrate and refluxed at 80 °C for 4 h. The concentration of the zirconium nitrate methanol solution was 0.05 mol / L, and the mass ratio of the metal salt to the dried product obtained in step (1) was 1.2. After refluxing, it was filtered and calcined in a muffle furnace at 550 °C for 6 h to obtain an MCM-41 molecular sieve support doped with 8 wt% of metal;

[0110] (3) 0.1 g of the support and 5 wt% of ruthenium trichloride (calculated as ruthenium element) based on the mass of the support were added to water with a water absorption capacity saturated with 0.1 g of the support. After stirring at 800 rpm for 2 h, it was left standing at room temperature for 24 h and dried at 120 °C for 10 h to obtain a catalyst precursor, which was reduced in a hydrogen atmosphere at 350 °C for 2 h to obtain a catalyst.

[0111] Application Example 1

[0112] Application of a metal-doped MCM-41 molecular sieve supported ruthenium metal catalyst in the reductive amination of glycolic acid to prepare glycine:

[0113] Glycolic acid, the catalyst obtained in Example 1, and ammonia water (25 wt%) were added to a 15 mL reactor, and the reactor was closed. Among them, the amount of glycolic acid used was 1 mmol, the molar amount of ruthenium in the catalyst was 0.8% of the molar amount of glycolic acid, and the amount of ammonia water used was 5 mL; the air in the reactor was replaced with hydrogen 5 times, 2.0 MPa of hydrogen was charged, the temperature was raised to 200 °C, and the reaction was carried out at this temperature for 4 h. After the reaction was completed, the reaction mixture was naturally cooled to room temperature, and the catalyst was removed by centrifugation. The reaction solution was rotary evaporated to remove the solvent ammonia water, internal standard trioxane and deuterated water were added and mixed evenly, and samples were taken for NMR analysis. The conversion rate of glycolic acid was 99%, and the yield of glycine was 55%.

[0114] Example 2

[0115] (1) 5 g of methyl orthosilicate, a surfactant, ammonium carbonate, and deionized water were mixed evenly. Among them: the surfactant was cetyltrimethylammonium chloride, the mass ratio of the surfactant to the mass of methyl orthosilicate was 0.8, the pH of the mixed solution was adjusted to 11.5 with ammonium carbonate, and the mass ratio of deionized water to the mass of methyl orthosilicate was 15; after the obtained mixed solution was aged at 30 °C for 18 h, it was hydrothermally treated at 150 °C for 15 h, filtered and dried at room temperature to obtain a dried product;

[0116] (2) The dried product obtained in step (1) was put into an ethanol solution of calcium chloride and refluxed at 90 °C for 2 h. The concentration of the calcium chloride ethanol solution was 0.1 mol / L, and the mass ratio of the metal salt to the dried product obtained in step (1) was 0.1. After refluxing, it was filtered and calcined in a muffle furnace at 500 °C for 5 h to obtain an MCM-41 molecular sieve support doped with 2 wt% of metal;

[0117] (3) 0.1 g of the support and 2 wt% of rhodium nitrate (calculated as rhodium element) based on the mass of the support were added to the water with the saturated water absorption amount of 0.1 g of the support. After stirring at 400 rpm for 6 h, it was left standing at room temperature for 12 h and dried at 110 °C for 12 h to obtain a catalyst precursor, which was reduced at 250 °C for 4 h under a hydrogen atmosphere to obtain a catalyst.

[0118] Application Example 2

[0119] Application of a catalyst with metal rhodium supported on doped metal MCM-41 molecular sieve in the reductive amination of glycolic acid to prepare glycine:

[0120] Glycolic acid, the catalyst obtained in Example 2, and ammonia water (25 wt%) were added to a 15 mL autoclave, and the autoclave was closed. Among them, the amount of glycolic acid used was 1 mmol, the molar amount of rhodium in the catalyst was 1.0% of the molar amount of glycolic acid, and the amount of ammonia water used was 5 mL; the air in the autoclave was replaced with hydrogen 5 times, 1.0 MPa of hydrogen was charged, the temperature was raised to 180 °C, and the reaction was carried out at this temperature for 12 h. After the reaction was completed, it was cooled and sampled for analysis according to the method described in Application Example 1. The conversion rate of glycolic acid was 99%, and the yield of glycine was 53%.

[0121] Example 3

[0122] (1) 5 g of tetrabutyl orthosilicate, a surfactant, sodium bicarbonate, and deionized water were mixed evenly. Among them: the surfactant was cetyltrimethylammonium chloride, the mass ratio of the surfactant to tetrabutyl orthosilicate was 0.1, the pH of the mixed solution was adjusted to 10.5 with sodium bicarbonate, and the mass ratio of deionized water to tetrabutyl orthosilicate was 8; after the obtained mixed solution was aged at 25 °C for 36 h, it was hydrothermally treated at 120 °C for 96 h, filtered and dried at room temperature to obtain a dried product;

[0123] (2) The dried product obtained in step (1) was put into an ether solution of aluminum nitrate and refluxed at 45 °C for 8 h. The concentration of the aluminum nitrate ether solution was 0.01 mol / L, and the mass ratio of the metal salt to the dried product obtained in step (1) was 1.5. After refluxing, it was filtered and calcined in a muffle furnace at 650 °C for 3 h to obtain an MCM-41 molecular sieve support doped with 18 wt% of metal;

[0124] (3) 0.1 g of the support and 10 wt% of palladium chloride (calculated as palladium element) based on the mass of the support were added to water with a saturated water absorption amount of 0.1 g of the support. After stirring at 250 rpm for 12 h, it was left standing at room temperature for 96 h and dried at 100 °C for 15 h to obtain a catalyst precursor, which was reduced at 200 °C for 8 h in a hydrogen atmosphere to obtain a catalyst.

[0125] Application Example 3

[0126] Application of a catalyst with metal-doped MCM-41 molecular sieve supported on metal palladium in the reductive amination of glycolic acid to prepare glycine:

[0127] Glycolic acid, the catalyst obtained in Example 3, and ammonia water (25 wt%) were added to a 15 mL autoclave, and the autoclave was closed. Among them, the amount of glycolic acid used was 1 mmol, the molar amount of palladium in the catalyst was 0.1% of the molar amount of glycolic acid, and the amount of ammonia water used was 5 mL; the air in the autoclave was replaced with hydrogen 5 times, 4.0 MPa of hydrogen was charged, the temperature was raised to 240 °C, and the reaction was carried out at this temperature for 2 h. After the reaction was completed, it was cooled and sampled for analysis according to the method described in Application Example 1. The conversion rate of glycolic acid was 99%, and the yield of glycine was 52%.

[0128] Example 4

[0129] (1) Mix 5 g of sodium silicate surfactant, ammonia water, and deionized water evenly. Among them: the surfactant is cetyltrimethylammonium bromide, the mass ratio of the surfactant to the mass of sodium silicate is 0.5, the ammonia water adjusts the pH of the mixed solution to 11.2, and the mass ratio of deionized water to the mass of sodium silicate is 10; After aging the obtained mixed solution at 80 °C for 10 h, perform hydrothermal treatment at 200 °C for 12 h, filter and dry at room temperature to obtain a dried product

[0130] (2) Put the dried product obtained in step (1) into an acetonitrile solution of cerium nitrate and reflux at 100 °C for 0.5 h. The concentration of the cerium nitrate acetonitrile solution is 0.08 mol / L, and the mass ratio of the metal salt to the dried product obtained in step (1) is 0.8. After refluxing, filter and calcine in a muffle furnace at 450 °C for 10 h to obtain an MCM-41 molecular sieve support doped with 20 wt% of metal;

[0131] (3) Add 0.1 g of the support and 12 wt% of nickel nitrate (calculated as nickel element) based on the mass of the support to water with a saturated water absorption capacity of 0.1 g of the support. Stir at 1200 rpm for 0.5 h, then let it stand at room temperature for 6 h, and dry at 180 °C for 5 h to obtain a catalyst precursor, which is reduced at 500 °C for 6 h under a hydrogen atmosphere to obtain a catalyst.

[0132] Application Example 4

[0133] Application of the metal-doped MCM-41 molecular sieve supported metal nickel catalyst in the reductive amination of glycolic acid to prepare glycine:

[0134] Add glycolic acid, the catalyst prepared in Example 4, and ammonia water (25 wt%) to a 15 mL reaction kettle, close the kettle. Among them, the dosage of glycolic acid is 1 mmol, the molar amount of nickel in the catalyst is 20% of the molar amount of glycolic acid, and the dosage of ammonia water is 5 mL; Replace the air in the kettle with hydrogen 5 times, fill in 3.0 MPa of hydrogen, heat up to 150 °C, and react at this temperature for 48 h. After the reaction is completed, cool and sample for analysis according to the method described in Application Example 1. The conversion rate of glycolic acid is 99%, and the yield of glycine is 53%.

[0135] Example 5

[0136] (1) Mix 5 g of tetraethyl orthosilicate, surfactant, ammonia water, and deionized water evenly. Among them: the surfactant is cetyltrimethylammonium chloride, the mass ratio of the surfactant to the mass of tetraethyl orthosilicate is 0.7, the ammonia water adjusts the pH of the mixed solution to 10.8, and the mass ratio of deionized water to the mass of tetraethyl orthosilicate is 9; After aging the obtained mixed solution at 35 °C for 14 h, perform hydrothermal treatment at 130 °C for 72 h, filter and dry at room temperature to obtain a dried product;

[0137] (2) Put the dried product obtained in step (1) into an ethyl ether solution of sodium chloride and reflux at 50 °C for 9 h. The concentration of the sodium chloride ethyl ether solution is 0.04 mol / L, and the mass ratio of the metal salt to the dried product obtained in step (1) is 0.9. After the reflux is completed, filter, and calcine in a muffle furnace at 550 °C for 9 h to obtain an MCM-41 molecular sieve support doped with 1 wt% of metal.

[0138] (3) Add 0.1 g of the support and cobalt chloride (calculated as cobalt element) accounting for 20 wt% of the mass of the support to the water with a saturated water absorption capacity of 0.1 g of the support. Stir at 500 rpm for 3 h, then let it stand at room temperature for 18 h, and dry at 160 °C for 6 h to obtain a catalyst precursor. Reduce it in a hydrogen atmosphere at 600 °C for 5 h to obtain the catalyst.

[0139] Application Example 5

[0140] Application of a catalyst of metal-doped MCM-41 molecular sieve supported with metal cobalt in the reductive amination of glycolic acid to prepare glycine:

[0141] Add glycolic acid, the catalyst prepared in Example 5, and ammonia water (25 wt%) into a 15 mL reaction kettle, close the kettle. Among them, the dosage of glycolic acid is 1 mmol, the molar amount of cobalt in the catalyst is 30% of the molar amount of glycolic acid, and the dosage of ammonia water is 5 mL; displace the air in the kettle with hydrogen 5 times, fill in 3.5 MPa of hydrogen, heat up to 260 °C, and react at this temperature for 6 h. After the reaction is completed, cool and sample for analysis according to the method described in Application Example 1. The conversion rate of glycolic acid is 99%, and the yield of glycine is 51%.

[0142] Example 6

[0143] (1) Mix 5 g of methyl orthosilicate, a surfactant, ammonium carbonate, and deionized water evenly. Among them: the surfactant is cetyltrimethylammonium bromide, the mass ratio of the surfactant to the mass of methyl orthosilicate is 0.3, the ammonium carbonate adjusts the pH of the mixed solution to 11.5, and the mass ratio of the deionized water to the mass of methyl orthosilicate is 10; after aging the obtained mixed solution at 45 °C for 42 h, conduct hydrothermal treatment at 190 °C for 30 h, filter and dry at room temperature to obtain a dried product;

[0144] (2) Put the dried product obtained in step (1) into a methanol solution of potassium nitrate and reflux at 80 °C for 5 h. The concentration of the potassium nitrate methanol solution is 0.09 mol / L, and the mass ratio of the metal salt to the dried product obtained in step (1) is 1.3. After the reflux is completed, filter, and calcine in a muffle furnace at 500 °C for 6 h to obtain an MCM-41 molecular sieve support doped with 15 wt% of metal.

[0145] (3) Add 0.1 g of the support and 30 wt% of copper nitrate (calculated as copper element) based on the mass of the support to the water with a water absorption capacity saturated with 0.1 g of the support. After stirring at 900 rpm for 5 h, let it stand at room temperature for 30 h, and then dry at 170 °C for 5 h to obtain the catalyst precursor, which is reduced at 550 °C for 3 h under a hydrogen atmosphere to obtain the catalyst.

[0146] Application Example 6

[0147] Application of the catalyst with metal-doped MCM-41 molecular sieve supported on metallic copper in the reductive amination of glycolic acid to prepare glycine:

[0148] Add glycolic acid, the catalyst obtained in Example 6, and ammonia water (25 wt%) to a 15 mL reaction kettle, close the kettle. Among them, the dosage of glycolic acid is 1 mmol, the molar amount of copper in the catalyst is 40% of the molar amount of glycolic acid, and the dosage of ammonia water is 5 mL; displace the air in the kettle with hydrogen 5 times, fill in 2.5 MPa of hydrogen, heat up to 220 °C, and react at this temperature for 36 h. After the reaction is completed, cool and sample for analysis according to the method described in Application Example 1. The conversion rate of glycolic acid is 99%, and the yield of glycine is 50%.

[0149] Example 7

[0150] (1) Mix 5 g of tetraethyl orthosilicate, surfactant, sodium bicarbonate, and deionized water evenly. Among them: the surfactant is cetyltrimethylammonium bromide, the mass ratio of the surfactant to tetraethyl orthosilicate is 0.4, sodium bicarbonate adjusts the pH of the mixed solution to 10.5, and the mass ratio of deionized water to tetraethyl orthosilicate is 12; after aging the obtained mixed solution at 60 °C for 12 h, perform hydrothermal treatment at 160 °C for 48 h, filter and dry at room temperature to obtain a dried product;

[0151] (2) Put the dried product obtained in step (1) into a methanol solution of magnesium nitrate and reflux at 70 °C for 10 h. The concentration of the magnesium nitrate methanol solution is 0.03 mol / L, and the mass ratio of the metal salt to the dried product obtained in step (1) is 0.6. After refluxing, filter and calcine in a muffle furnace at 600 °C for 8 h to obtain an MCM-41 molecular sieve support doped with 6 wt% of metal;

[0152] (3) Add 0.1 g of the support and 0.2 wt% of chloroplatinic acid (calculated as platinum element) based on the mass of the support to the water with a water absorption capacity saturated with 0.1 g of the support. After stirring at 1000 rpm for 4 h, let it stand at room temperature for 48 h, and then dry at 150 °C for 8 h to obtain the catalyst precursor, which is reduced at 450 °C for 1 h under a hydrogen atmosphere to obtain the catalyst.

[0153] Application Example 7

[0154] Application of a catalyst composed of platinum supported on metal-doped MCM-41 molecular sieve in the reductive amination of glycolic acid to prepare glycine:

[0155] Glycolic acid, the catalyst obtained in Example 7, and ammonia water (25 wt%) were added to a 15 mL autoclave, and the autoclave was closed. Among them, the amount of glycolic acid used was 1 mmol, the molar amount of platinum in the catalyst was 10% of the molar amount of glycolic acid, and the amount of ammonia water used was 5 mL. The air in the autoclave was replaced with hydrogen 5 times, 1.5 MPa of hydrogen was charged, the temperature was raised to 250 °C, and the reaction was carried out at this temperature for 8 h. After the reaction was completed, it was cooled and sampled for analysis according to the method described in Application Example 1. The conversion rate of glycolic acid was 99%, and the yield of glycine was 53%.

[0156] Example 8

[0157] (1) 5 g of tetrabutyl orthosilicate, a surfactant, ammonia water, and deionized water were mixed evenly. Among them: the surfactant was cetyltrimethylammonium chloride, the mass ratio of the surfactant to the mass of tetrabutyl orthosilicate was 0.6, the pH of the mixed solution was adjusted to 10.8 with ammonia water, and the mass ratio of deionized water to the mass of tetrabutyl orthosilicate was 14. After the obtained mixed solution was aged at 40 °C for 48 h, it was hydrothermally treated at 140 °C for 36 h, filtered and dried at room temperature to obtain a dried product;

[0158] (2) The dried product obtained in step (1) was placed in an ether solution of ferric chloride and refluxed at 60 °C for 1 h. The concentration of the ferric chloride ether solution was 0.06 mol / L, and the mass ratio of the metal salt to the dried product obtained in step (1) was 1.0. After refluxing, it was filtered and calcined in a muffle furnace at 580 °C for 4 h to obtain an MCM-41 molecular sieve support doped with 5 wt% of metal;

[0159] (3) 0.1 g of the support and 8 wt% of ruthenium trichloride (calculated based on ruthenium element) of the mass of the support were added to water with a saturated water absorption amount of 0.1 g of the support. After stirring at 600 rpm for 1 h, it was left standing at room temperature for 36 h and dried at 130 °C for 9 h to obtain a catalyst precursor, which was reduced in a hydrogen atmosphere at 300 °C for 3 h to obtain a catalyst.

[0160] Application Example 8

[0161] Application of a catalyst composed of ruthenium supported on metal-doped MCM-41 molecular sieve in the reductive amination of glycolic acid to prepare glycine:

[0162] Glycolic acid, the catalyst obtained in Example 8, and ammonia water (25 wt%) were added to a 15 mL reactor, and the reactor was closed. Among them, the amount of glycolic acid used was 1 mmol, the molar amount of ruthenium in the catalyst was 5% of the molar amount of glycolic acid, and the amount of ammonia water used was 5 mL; the air in the reactor was replaced with hydrogen 5 times, 2.0 MPa of hydrogen was charged, the temperature was raised to 230 °C, and the reaction was carried out at this temperature for 10 h. After the reaction was completed, it was cooled and sampled for analysis according to the method described in Application Example 1. The conversion rate of glycolic acid was 99%, and the yield of glycine was 51%.

[0163] Example 9

[0164] (1) 5 g of sodium silicate, a surfactant, ammonium carbonate, and deionized water were mixed evenly. Among them: the surfactant was cetyltrimethylammonium bromide, the mass ratio of the surfactant to the mass of sodium silicate was 0.2, the ammonium carbonate adjusted the pH of the mixed solution to 11.2, and the mass ratio of deionized water to the mass of sodium silicate was 11; after the obtained mixed solution was aged at 70 °C for 30 h, it was hydrothermally treated at 170 °C for 18 h, filtered and dried at room temperature to obtain a dried product;

[0165] (2) The dried product obtained in step (1) was put into a methanol solution of strontium chloride and refluxed at 85 °C for 3 h. The concentration of the strontium chloride methanol solution was 0.07 mol / L, and the mass ratio of the metal salt to the dried product obtained in step (1) was 0.4. After refluxing, it was filtered and calcined in a muffle furnace at 520 °C for 7 h to obtain an MCM-41 molecular sieve support doped with 12 wt% of metal;

[0166] (3) 0.1 g of the support and rhodium nitrate (calculated as rhodium element) accounting for 4 wt% of the mass of the support were added to water with a saturated water absorption amount of 0.1 g of the support. After stirring at 700 rpm for 8 h, it was left standing at room temperature for 72 h, dried at 140 °C for 7 h to obtain a catalyst precursor, and reduced in a hydrogen atmosphere at 400 °C for 2 h to obtain a catalyst.

[0167] Application Example 9

[0168] Application of a catalyst with metal-doped MCM-41 molecular sieve supported on metal rhodium in the reductive amination of glycolic acid to prepare glycine:

[0169] Glycolic acid, the catalyst obtained in Example 9, and ammonia water (25 wt%) were added to a 15 mL reactor, and the reactor was closed. Among them, the amount of glycolic acid used was 1 mmol, the molar amount of rhodium in the catalyst was 2% of the molar amount of glycolic acid, and the amount of ammonia water used was 5 mL; the air in the reactor was replaced with hydrogen 5 times, 1.5 MPa of hydrogen was charged, the temperature was raised to 210 °C, and the reaction was carried out at this temperature for 14 h. After the reaction was completed, it was cooled and sampled for analysis according to the method described in Application Example 1. The conversion rate of glycolic acid was 99%, and the yield of glycine was 53%.

[0170] Example 10

[0171] (1) Mix 5 g of tetraethyl orthosilicate, surfactant, ammonia water, and deionized water evenly. Among them: the surfactant is cetyltrimethylammonium bromide, the mass ratio of the surfactant to tetraethyl orthosilicate is 0.5, the ammonia water adjusts the pH of the mixed solution to 11.0, and the mass ratio of deionized water to tetraethyl orthosilicate is 13; After aging the obtained mixed solution at 55 °C for 20 h, perform hydrothermal treatment at 155 °C for 42 h, filter and dry at room temperature to obtain a dried product;

[0172] (2) Put the dried product obtained in step (1) into an ethanol solution of lithium chloride and reflux at 100 °C for 6 h. The concentration of the lithium chloride ethanol solution is 0.02 mol / L, and the mass ratio of the metal salt to the dried product obtained in step (1) is 0.7. After refluxing, filter and calcine in a muffle furnace at 580 °C for 8 h to obtain an MCM-41 molecular sieve support doped with 3 wt% of metal;

[0173] (3) Add 0.1 g of the support and 3 wt% of palladium chloride (calculated as palladium element) based on the mass of the support to water with a saturated water absorption capacity of 0.1 g of the support. Stir at 1100 rpm for 7 h, then let stand at room temperature for 42 h, and dry at 115 °C for 11 h to obtain a catalyst precursor, which is reduced at 280 °C for 7 h under a hydrogen atmosphere to obtain a catalyst.

[0174] Application Example 10

[0175] Application of the catalyst of metal-doped MCM-41 molecular sieve supported on metallic palladium in the reductive amination of glycolic acid to prepare glycine:

[0176] Add glycolic acid, the catalyst prepared in Example 10, and ammonia water (25 wt%) to a 15 mL reaction kettle, close the kettle. Among them, the dosage of glycolic acid is 1 mmol, the molar amount of palladium in the catalyst is 8% of the molar amount of glycolic acid, and the dosage of ammonia water is 5 mL; Replace the air in the kettle with hydrogen 5 times, fill in 2.5 MPa of hydrogen, heat up to 190 °C, and react at this temperature for 18 h. After the reaction is completed, cool and sample for analysis according to the method described in Application Example 1. The conversion rate of glycolic acid is 99%, and the yield of glycine is 51%.

[0177] Example 11

[0178] (1) Mix 5 g of tetramethyl orthosilicate, surfactant, ammonium carbonate, and deionized water evenly. Among them: the surfactant is cetyltrimethylammonium chloride, the mass ratio of the surfactant to tetramethyl orthosilicate is 0.3, the ammonium carbonate adjusts the pH of the mixed solution to 10.5, and the mass ratio of deionized water to tetramethyl orthosilicate is 11; After aging the obtained mixed solution at 65 °C for 26 h, perform hydrothermal treatment at 165 °C for 22 h, filter and dry at room temperature to obtain a dried product;

[0179] (2) Put the dried product obtained in step (1) into an acetonitrile solution of cesium chloride and reflux at 90 °C for 7 h. The concentration of the cesium chloride acetonitrile solution is 0.08 mol / L, and the mass ratio of the metal salt to the dried product obtained in step (1) is 1.4. After the reflux ends, filter, and calcine in a muffle furnace at 600 °C for 4 h to obtain an MCM-41 molecular sieve support doped with 10 wt% of metal.

[0180] (3) Add 0.1 g of the support and nickel nitrate (calculated as nickel element) accounting for 25 wt% of the mass of the support to water with a saturated water absorption capacity of 0.1 g of the support. Stir at 300 rpm for 10 h, then let it stand at room temperature for 54 h, and dry at 125 °C for 13 h to obtain a catalyst precursor, which is reduced in a hydrogen atmosphere at 480 °C for 6 h to obtain the catalyst.

[0181] Application Example 11

[0182] Application of a catalyst composed of metal-doped MCM-41 molecular sieve supported with metallic nickel in the reductive amination of glycolic acid to prepare glycine:

[0183] Add glycolic acid, the catalyst prepared in Example 11, and ammonia water (25 wt%) to a 15 mL autoclave, close the autoclave. Among them, the dosage of glycolic acid is 1 mmol, the molar amount of nickel in the catalyst is 25% of the molar amount of glycolic acid, and the dosage of ammonia water is 5 mL; displace the air in the autoclave with hydrogen 5 times, fill in 2.0 MPa of hydrogen, heat up to 245 °C, and react at this temperature for 5 h. After the reaction ends, cool and sample for analysis according to the method described in Application Example 1. The conversion rate of glycolic acid is 99%, and the yield of glycine is 50%.

[0184] Example 12

[0185] (1) Mix 5 g of tetrabutyl orthosilicate, surfactant, ammonia water, and deionized water evenly. Among them: the surfactant is cetyltrimethylammonium bromide, the mass ratio of the surfactant to tetrabutyl orthosilicate is 0.4, the ammonia water adjusts the pH of the mixed solution to 11.5, and the mass ratio of deionized water to tetrabutyl orthosilicate is 13; after aging the obtained mixed solution at 75 °C for 32 h, perform hydrothermal treatment at 175 °C for 52 h, filter and dry at room temperature to obtain a dried product;

[0186] (2) Put the dried product obtained in step (1) into a methanol solution of manganese nitrate and reflux at 90 °C for 6 h. The concentration of the manganese nitrate methanol solution is 0.09 mol / L, and the mass ratio of the metal salt to the dried product obtained in step (1) is 0.5. After the reflux ends, filter, and calcine in a muffle furnace at 500 °C for 8 h to obtain an MCM-41 molecular sieve support doped with 4 wt% of metal.

[0187] (3) 0.1 g of the support and 1 wt% of chloroplatinic acid (calculated as platinum element) based on the mass of the support were added to water with a mass equal to the saturated water absorption capacity of 0.1 g of the support. After stirring at 650 rpm for 9 h, the mixture was allowed to stand at room temperature for 28 h and then dried at 135 °C for 14 h to obtain a catalyst precursor, which was reduced in a hydrogen atmosphere at 220 °C for 3 h to obtain the catalyst.

[0188] Application Example 12

[0189] Application of a catalyst comprising platinum supported on a metal-doped MCM-41 molecular sieve in the reductive amination of glycolic acid to prepare glycine:

[0190] Glycolic acid, the catalyst prepared in Example 12, and ammonia water (25 wt%) were added to a 15 mL autoclave, and the autoclave was closed. Among them, the amount of glycolic acid used was 1 mmol, the molar amount of platinum in the catalyst was 3% of the molar amount of glycolic acid, and the amount of ammonia water used was 5 mL; the air in the autoclave was replaced with hydrogen 5 times, 1.0 MPa of hydrogen was charged, and the temperature was raised to 170 °C, and the reaction was carried out at this temperature for 24 h. After the reaction was completed, it was cooled and sampled for analysis according to the method described in Application Example 1. The conversion rate of glycolic acid was 99%, and the yield of glycine was 52%.

[0191] Example 13

[0192] (1) 5 g of tetraethyl orthosilicate, a surfactant, sodium bicarbonate, and deionized water were mixed evenly. Among them: the surfactant was cetyltrimethylammonium bromide, the mass ratio of the surfactant to tetraethyl orthosilicate was 0.5, the pH of the mixed solution was adjusted to 10.8 with sodium bicarbonate, and the mass ratio of deionized water to tetraethyl orthosilicate was 15; after the obtained mixed solution was aged at 55 °C for 16 h, it was hydrothermally treated at 185 °C for 16 h, filtered, and dried at room temperature to obtain a dried product;

[0193] (2) The dried product obtained in step (1) was placed in an ether solution of barium chloride and refluxed at 55 °C for 4 h. The concentration of the barium chloride ether solution was 0.05 mol / L, and the mass ratio of the metal salt to the dried product obtained in step (1) was 1.1. After refluxing, it was filtered and calcined in a muffle furnace at 550 °C for 8 h to obtain an MCM-41 molecular sieve support doped with 7 wt% of metal;

[0194] (3) 0.1 g of the support and 6 wt% of palladium chloride (calculated as palladium element) based on the mass of the support were added to water with a mass equal to the saturated water absorption capacity of 0.1 g of the support. After stirring at 850 rpm for 11 h, the mixture was allowed to stand at room temperature for 32 h and then dried at 145 °C for 8 h to obtain a catalyst precursor, which was reduced in a hydrogen atmosphere at 320 °C for 4 h to obtain the catalyst.

[0195] Application Example 13

[0196] Application of Palladium-Metal-Loaded Catalyst on Metal-Doped MCM-41 Molecular Sieve in the Preparation of Glycine by Reductive Amination of Glycolic Acid

[0197] Glycolic acid, the catalyst prepared in Example 13, and ammonia water (25 wt%) were added into a 15 mL autoclave, and the autoclave was closed. Among them, the dosage of glycolic acid was 1 mmol, the molar amount of palladium in the catalyst was 4% of the molar amount of glycolic acid, and the dosage of ammonia water was 5 mL. The air in the autoclave was replaced with hydrogen 5 times, 1.5 MPa hydrogen was charged, and the temperature was raised to 225 °C, and the reaction was carried out at this temperature for 16 h. After the reaction was completed, it was cooled and sampled for analysis according to the method described in Application Example 1. The conversion rate of glycolic acid was 99%, and the yield of glycine was 53%.

[0198] Application Example 14

[0199] After the catalyst was prepared and reduced according to the conditions of Example 1, it was used in the reductive amination reaction of glycolic acid according to the conditions of Application Example 1. Different from Application Example 1: after the reaction was completed, the catalyst was centrifuged and separated, and the catalyst was continuously centrifuged and washed with water 5 times, and the reductive amination reaction of glycolic acid was recycled again. In this way, the catalyst was recycled 5 times, and the results are shown in Table 1.

[0200] Table 1. Recycling effect of the catalyst on the reductive amination of glycolic acid

[0201] Number of cycles Conversion rate of glycolic acid (C%) Yield of glycine (C%) 1 99 55 2 99 54 3 99 53 4 99 53 5 99 52

[0202] It can be seen from Table 1 that the prepared catalyst can still maintain high catalytic activity after being recycled 5 times for the reductive amination of glycolic acid, and the yield of glycine remains above 52%. The catalysts provided in Examples 2 to 13 were recycled under the same conditions and could also maintain high catalytic activity. After being recycled 5 times, the yield of glycine remained above 45%.

[0203] Comparative Example 1

[0204] After the catalyst was prepared and reduced according to the conditions of Example 1 and used in the reductive amination reaction of glycolic acid, different from Example 1: during the catalyst preparation process, after the support was hydrothermally treated, it was filtered and dried at room temperature to obtain a dried product. The obtained dried product was calcined in a muffle furnace at 550 °C for 6 h to obtain an MCM-41 molecular sieve support, and then an MCM-41 molecular sieve-supported ruthenium metal catalyst was obtained through subsequent operations. The conversion rate of glycolic acid was 99%, and the yield of glycine was 20%.

[0205] The preparation method of the present invention has a simple and easy operation process, the catalyst is easy to separate from the system, and it can still maintain high catalytic activity after being recycled many times. The prepared hydrogenation metal-supported catalyst on the metal-doped MCM-41 molecular sieve can selectively prepare glycine in the reductive amination of glycolic acid, and has broad application prospects.

[0206] As described above, these are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the relevant art, without departing from the technical solution of the present application, making some changes or modifications using the disclosed technical content above is equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A method for catalyzing the preparation of glycine from glycolic acid, characterized in that, Hydrogen is introduced into a mixed solution containing glycolic acid, a supported catalyst, and ammonia water for reductive amination reaction to obtain glycine; The supported catalyst includes a carrier and a hydrogenation metal supported on the carrier; The carrier is a metal-doped MCM-41 molecular sieve; The hydrogenation metal is selected from at least one of Ru, Pd, Pt, Rh, Ni, Co, and Cu; The doped metal is selected from at least one of Li, Na, K, Cs, Mg, Ca, Ba, Sr, Mn, Al, Zr, Ce, and Fe.

2. The method according to claim 1, wherein in the supported catalyst, the loading amount of the hydrogenation metal is 0.2-30 wt%, wherein the mass of the supported catalyst is based on the mass of the carrier, and the mass of the hydrogenation metal is based on the mass of the hydrogenation metal element.

3. The method according to claim 1, wherein in the supported catalyst, the loading amount of the hydrogenation metal is 2-20 wt%.

4. The method according to claim 3, wherein in the supported catalyst, the loading amount of the hydrogenation metal is 2-10 wt%.

5. The method according to claim 1, wherein in the carrier, the doping amount of the doped metal is 1-20 wt%, wherein the mass of the doped metal is based on the mass of the doped metal element.

6. The method according to claim 1, characterized in that The preparation method of the supported catalyst includes: (1) Mixing a surfactant, a silicon source, an alkaline substance and water, aging, hydrothermally treating, and filtering to obtain a precipitate; (2) Placing the precipitate obtained in step (1) into an organic solution containing an inorganic salt of a doped metal and refluxing, and calcining to obtain the carrier substance A; (3) Impregnating the carrier into a solution containing a hydrogenation metal precursor and reducing to obtain the supported catalyst.

7. The method according to claim 1, wherein the surfactant is selected from at least one of cetyltrimethylammonium bromide and cetyltrimethylammonium chloride; the silicon source is selected from at least one of methyl orthosilicate, ethyl orthosilicate, butyl orthosilicate, and sodium silicate; the alkaline substance is selected from at least one of ammonia water, ammonium carbonate, and sodium bicarbonate.

8. The method according to claim 6, characterized in that, The inorganic salt of the doped metal is selected from at least one of nitrate and chloride.

9. The method according to claim 6, wherein The organic solution containing the inorganic salt of the doped metal further includes an organic solvent; the organic solvent is selected from at least one of methanol, ethanol, ether, and acetonitrile.

10. The method according to claim 6, characterized in that, The hydrogenation precursor is a compound containing a hydrogenation metal, and the compound containing a hydrogenation metal is selected from at least one of ruthenium trichloride, rhodium nitrate, palladium chloride, chloroplatinic acid, nickel nitrate, cobalt chloride, and copper nitrate.

11. The method according to claim 6, characterized in that The mass ratio of the surfactant to the silicon source is 0.1-0.8; the alkaline substance adjusts the pH of the mixed solution to 10.5-11.5; the mass ratio of water to the silicon source is 8-15; wherein the surfactant is based on the weight of the surfactant itself, the ammonia water is based on the weight of the ammonia water itself, the water is based on the weight of the water itself, and the silicon source is based on the weight of the silicon source itself.

12. The preparation method according to claim 6, wherein In the organic solution containing the inorganic salt doped with a metal, the concentration of the inorganic salt doped with the metal is 0.01 to 0.1 mol / L, and the molar amount of the inorganic salt doped with the metal is based on the molar amount of the doped metal element.

13. The preparation method according to claim 6, characterized in that the aging temperature is 25 to 80 °C, and the aging time is 10 to 48 h; the hydrothermal temperature is 120 to 200 °C, and the hydrothermal time is 12 to 96 h; the reflux temperature is 45 to 100 °C, and the reflux time is 0.5 to 10 h; the calcination temperature is 450 to 650 °C; the calcination time is 3 to 10 h; the reduction is carried out in a hydrogen atmosphere; the reduction temperature is 200 to 600 °C; the reduction time is 1 to 8 h.

14. The method according to claim 1, characterized in that the molar amount of the catalyst is 0.1 to 40% of the molar amount of the glycolic acid, wherein the molar amount of the catalyst is based on the molar amount of the hydrogenation metal element.

15. The method according to claim 1, characterized in that the specific conditions of the reductive amination reaction include: the hydrogen partial pressure is 1.0 to 4.0 MPa; the reaction temperature is 150 to 260 °C; the reaction time is 2 to 48 h.

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