Method and process device for preparing acetic acid by catalyzing methyl acetate

Abstract

The invention discloses a method and a process device for preparing acetic acid through catalysis of methyl acetate, and in a reaction system containing a catalyst, the methyl acetate is contacted and reacted with carbon monoxide and water to prepare the acetic acid; the catalyst contains an active element M, and M is Rh and / or Ir. According to the method, methyl acetate reacts with carbon monoxide and water under metal catalysis under the action of an Rh or Ir catalyst to be converted into acetic acid and corresponding acid. Different from a traditional concentrated sulfuric acid or benzenesulfonic acid resin catalyzed methyl acetate hydrolysis catalytic reaction process, the invention creatively provides a method for converting methyl acetate into acetic acid in a high-activity and high-selectivity manner through reaction of metal catalyzed methyl acetate with carbon monoxide and water under the action of an Rh or Ir catalyst; the catalytic activity is more than 10 times that of concentrated sulfuric acid or benzenesulfonic acid resin for catalyzing the hydrolysis reaction of methyl acetate to prepare acetic acid, and the method can also be applied to other methyl ester compounds, such as methyl formate, methyl propionate, methyl butyrate and methyl benzoate.

Description

Technical Field

[0001] The present application relates to a method and process device for catalytically producing acetic acid from methyl acetate, belonging to the field of chemical catalytic conversion. Background Art

[0002] Acetic acid is one of the most important organic chemical raw materials. It is mainly used to produce important chemical products such as vinyl acetate, acetic anhydride, cellulose acetate, acetates, terephthalic acid, and chloroacetic acid. It is widely used in chemical, light industry, textile, pharmaceutical, printing and dyeing industries.

[0003] Currently, the main methods for producing acetic acid include acetaldehyde oxidation, direct olefin oxidation, methyl ester hydrolysis, and methanol carbonylation. Methyl ester hydrolysis and methanol carbonylation are the most commonly used industrial methods. The methyl ester hydrolysis method, such as the hydrolysis of methyl acetate, operates at relatively low pressures, typically atmospheric pressure. However, it requires the use of an acidic resin or concentrated sulfuric acid as a catalyst, and requires temperatures of 230-240°C. The reactant conversion rate is low, at 30-50%, and the space-time yield of the acetic acid product is low, at 0.5 g per gram of catalyst per hour. Continuous production consumes a high amount of energy. Summary of the Invention

[0004] In response to the shortcomings of the existing methyl acetate hydrolysis method, this patent innovatively proposes the use of metal catalysis, which can greatly improve the conversion rate of methyl acetate and the space-time yield of product acetic acid. The conversion rate of methyl acetate can be >90% to 95%, and the space-time yield of product acetic acid is 4 to 6 g per gram of catalyst per hour. The activity is 6 to 10 times higher than that of conventional concentrated sulfuric acid or benzenesulfonic acid-catalyzed methyl ester hydrolysis, and the energy consumption is greatly reduced. It is distinctively innovative. This method can also be extended to other methyl ester compounds, such as methyl formate, methyl propionate, methyl butyrate, methyl benzoate, etc.

[0005] The present invention aims to provide a novel process for producing acetic acid from methyl acetate.

[0006] In one aspect of the present application, a method for catalytically preparing acetic acid from methyl acetate is provided, wherein methyl acetate reacts with carbon monoxide and water over an Rh or Ir catalyst to be converted into acetic acid in a single step with high activity and selectivity, thereby achieving continuous engineering scale-up and production of methyl acetate to acetic acid.

[0007] Optionally, in a reaction system containing a catalyst, methyl acetate is contacted with carbon monoxide and water to react to produce acetic acid;

[0008] The catalyst contains an active element M, and the active element M is Rh and / or Ir.

[0009] In the present application, it is necessary to use an Rh or Ir-based catalyst, which can be a homogeneous catalyst or a supported heterogeneous catalyst.

[0010] Optionally, the catalyst is a homogeneous catalyst and / or a supported heterogeneous catalyst;

[0011] In the catalyst, the geometric molecular structure of the active element M is [M(CO) x I y ] δ- , wherein M is at least one of Rh and Ir;

[0012] 0≤x≤2, 0≤y≤4, 0≤δ≤2.

[0013] Optionally, when the catalyst is a supported heterogeneous catalyst, it further comprises a carrier;

[0014] The carrier is an inorganic carbon carrier and / or a porous organic carbon carrier;

[0015] The inorganic carbon carrier is at least one of coconut shell activated carbon and apricot shell activated carbon, and the surface is modified with O functional groups;

[0016] The porous organic carbon carrier is at least one of artificial carbons containing N, O, P, and S functional groups.

[0017] Optionally, in the supported heterogeneous catalyst, the mass loading of the active element M is 0.1 to 2.0 wt%.

[0018] Optionally, the mass loading of the active element M is independently selected from any value among 0.1wt%, 0.2wt%, 0.5wt%, 0.8wt%, 1.0wt%, 1.5wt%, 2.0wt% or a range between any two of the above values.

[0019] Optionally, when the support is an inorganic carbon support, the active element M is anchored by interacting with the N, O, P, and S functional groups on the support surface through coordination bonds.

[0020] Optionally, when the support is a porous organic carbon support, the support surface contains organic functional groups and / or inorganic functional groups;

[0021] Wherein, the organic functional group is at least one of N, O, P, and S organic functional groups containing lone pair electrons;

[0022] The inorganic functional group is [N] + 、[P] + At least one of the inorganic functional groups of the structure;

[0023] The active element M interacts and anchors with the carrier in one of the ionic bond, ionic bond and coordination bond multiple coordination forms.

[0024] As a specific embodiment, when Rh or Ir is a homogeneous catalyst, the concentration of the substrate (methyl acetate) is 10 to 10000 ppm; the geometric molecular structure of Rh or Ir is [M(CO) x I y ] δ- , M is one or more of Rh or Ir, 0≤x≤2; 0≤y≤4; 0≤δ≤2.

[0025] When Rh or Ir is a supported heterogeneous catalyst, the geometric molecular structure of Rh or Ir is [M(CO) x I y ] δ- , M is one or more of Rh or Ir, 0≤x≤2; 0≤y≤4; 0≤δ≤2. When the carrier is an inorganic carbon carrier, Rh or Ir interacts and anchors with the N, O, P, S functional groups on the carrier surface through coordination bonds; when the carrier is a porous organic carbon carrier, the surface organic functional groups containing lone pairs of electrons such as N, O, P, S or [N] + 、[P] + The inorganic functional groups of the structure, or a combination of the two. Rh or Ir is anchored to the carrier through ionic bonds or ionic bonds + coordination bonds.

[0026] Optionally, in the catalyst, the precursor of the active element M is selected from at least one of M element, chloride containing element M, bromide containing element M, iodide containing element M, chlorinated carbonyl containing element M, brominated carbonyl containing element M, iodinated carbonyl containing element M, acetic acid compound containing element M, triphenylphosphine coordination compound containing element M, and chlorinated carbonyl compound containing element M.

[0027] Optionally, the catalyst further includes a promoter element I, wherein the promoter element I is at least one of Li, Na, and K;

[0028] In the catalyst, the molar ratio of the auxiliary element I to the active element is 0.1 to 10:1 times;

[0029] The precursor of the auxiliary element I is selected from one of iodide salts or acetates containing the auxiliary element I.

[0030] Optionally, the molar ratio of the auxiliary element I to the active element is independently selected from any value of 0.1:1, 1:1, 2:1, 5:1, 8:1, 10:1 or a range between any two of the above values.

[0031] Optionally, the catalyst further includes a promoter element II, and the promoter element II is at least one of Ru, Mn, and La;

[0032] In the catalyst, the molar ratio of the auxiliary element II to the active element is 1 to 5:1.

[0033] Optionally, the molar ratio of the auxiliary element II to the active element is independently selected from any value among 1:1, 2:1, 3:1, 4:1, 5:1 or a range between any two of the above.

[0034] Optionally, the reaction system further comprises a co-catalyst, that is, a certain amount of co-catalyst needs to be added during the reaction process;

[0035] The co-catalyst is methyl iodide;

[0036] The mass of the co-catalyst is 5% to 20% of the mass of the methyl acetate.

[0037] Optionally, the mass of the co-catalyst is independently selected from any value among 5%, 10%, 16%, 20% of the mass of the methyl acetate, or a range between any two of the above values.

[0038] Optionally, the reaction system further comprises hydrogen, that is, a certain amount of hydrogen is added during the reaction to maintain the stability or activity of the catalyst;

[0039] The volume content of the hydrogen is 2% to 10% of the volume of CO.

[0040] Optionally, the volume content of hydrogen is independently selected from any value among 2%, 4%, 6%, 8%, 10% of the volume of CO, or a range between any two of the above.

[0041] Optionally, in the reaction system, the mass space velocity of methyl acetate is 2 to 6 h -1 ;

[0042] The molar ratio of carbon monoxide to methyl acetate is 0.5 to 2;

[0043] The mass content of the water is 5% to 30% of the methyl acetate.

[0044] Optionally, when the catalyst is a homogeneous catalyst, the concentration of methyl acetate is 10 to 10,000 ppm.

[0045] Alternatively, the mass space velocity of methyl acetate is independently selected from 2h -1 , 3h -1 , 4h -1 , 5h -1 , 6h -1 Any value in or a range of values ​​between any two of the above.

[0046] Optionally, the molar ratio of carbon monoxide to methyl acetate is independently selected from any value among 0.5, 1, 1.5, 2, or a range between any two of the above.

[0047] Optionally, the mass content of water is independently selected from any value among 5%, 10%, 15%, 20%, 30% or a range between any two of the above values ​​based on the mass of methyl acetate.

[0048] Optionally, the reaction pressure is 1 to 5 MPa;

[0049] The reaction time is 150-250°C.

[0050] Optionally, the reaction pressure is independently selected from any value among 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, or a range between any two of the above values.

[0051] Optionally, the reaction time is independently selected from any value among 150°C, 175°C, 200°C, 235°C, 250°C, or a range between any two of the above values.

[0052] Another aspect of the present application provides a process apparatus for preparing acetic acid using the above-mentioned method, characterized in that the process apparatus comprises:

[0053] The process device comprises a reaction unit and a separation unit connected in sequence;

[0054] The separation unit includes a high-pressure separation tank, a high-pressure washing tower, a low-pressure flash tank, a low-temperature washing tower, and a deweighting tower, wherein the top outlet I of the high-pressure separation tank is connected to the high-pressure washing tower, and the bottom outlet II of the high-pressure separation tank is connected to the low-pressure flash tank; the top outlet II and the bottom outlet II of the high-pressure washing tower are respectively connected to the reaction unit; the top outlet III of the low-pressure flash tank is connected to the low-temperature washing tower, and the bottom outlet III of the low-pressure flash tank is connected to the deweighting tower; the top outlet IV and the bottom outlet IV of the low-temperature washing tower are respectively connected to the reaction unit, and are connected to a discharge port for venting gas; the deweighting tower is provided with a top outlet V and a bottom outlet V;

[0055] The high-pressure separation tank is connected to the reaction unit;

[0056] The reaction unit is composed of one reactor or two reactors connected in series, which further improves the yield of the product.

[0057] Optionally, the reactor is at least one of a tank reactor, a bubble column reactor, and a fixed bed reactor;

[0058] The reactor is made of C276 or Zr704 and is corrosion-resistant.

[0059] The product also contains trace amounts of by-products such as methanol, methyl ether, acetaldehyde, propionic acid, methane, and carbon dioxide.

[0060] As a specific implementation method, the separation of the products after the reaction requires the use of a high-pressure separation tank, a high-pressure washing tower, a low-pressure flash tank, a low-temperature washing tower, an acetic acid dehydration tower or an acetic acid refining tower for product separation and purification.

[0061] The high-pressure separator is primarily used to separate the gas and liquid phases, the low-pressure flash tank is primarily used to separate heavy components such as acetic acid and water, and the high-pressure scrubber is used to scrub methyl iodide from the gas phase. The low-temperature scrubber is primarily used to recover as much iodine as possible from the product to meet environmental impact assessment emission standards. Unreacted methyl ester, methanol in the product, and methyl iodide are returned to the reactor. The acetic acid separation and refining tower is primarily used to separate the corresponding acid from the acetic acid in the acetic acid.

[0062] By adopting the present method, acetic acid can be prepared from methyl ester in one step with high activity and high selectivity.

[0063] The beneficial effects of this application include:

[0064] (1) Different from the traditional catalytic reaction process of hydrolyzing methyl acetate catalyzed by concentrated sulfuric acid or benzenesulfonic acid resin, this application innovatively proposes to convert methyl acetate into acetic acid with high activity and high selectivity by reacting methyl acetate with carbon monoxide and water in the presence of Rh or Ir catalysts through metal catalysis.

[0065] (2) This method utilizes metal catalysis to significantly increase the conversion rate of methyl acetate and the space-time yield of the product acetic acid. The conversion rate of methyl acetate can reach >90% to 95%, and the space-time yield of the product acetic acid is 4 to 6 g per gram of catalyst per hour. This activity is 6 to 10 times higher than that of conventional concentrated sulfuric acid or benzenesulfonic acid-catalyzed methyl ester hydrolysis, and the energy consumption is significantly reduced, which is a distinct innovation. This method can also be extended to other methyl ester compounds, such as methyl formate, methyl propionate, methyl butyrate, and methyl benzoate. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 This is a HAADF-STEM image of the activated carbon AC-supported Ir-Ru catalyst (Ir-Ru / AC) used in Example 2 of the present application, where the scale is 5 nm, and the metal atoms can be dispersed at the single-atom level.

[0067] Figure 2 This is a simplified flow chart of the process for producing acetic acid by one-step catalytic conversion of methyl acetate in the examples of this application. DETAILED DESCRIPTION

[0068] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0069] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0070] The process equipment and process flow used in the embodiments of this application are as follows Figure 2 As shown, it includes a reactor, a high-pressure separation tank, a high-pressure washing tower, a low-pressure flash tank, a low-temperature washing tower, and a de-weighting tower, wherein the top outlet I of the high-pressure separation tank is connected to the high-pressure washing tower, and the bottom outlet II of the high-pressure separation tank is connected to the low-pressure flash tank; the top outlet II and the bottom outlet II of the high-pressure washing tower are respectively connected to the reactor; the top outlet III of the low-pressure flash tank is connected to the low-temperature washing tower, and the bottom outlet III of the low-pressure flash tank is connected to the de-weighting tower; the top outlet IV and the bottom outlet IV of the low-temperature washing tower are respectively connected to the reactor and are connected to a discharge port for venting gas; the de-weighting tower is provided with a top outlet V and a bottom outlet V; the high-pressure separation tank is connected to the reactor.

[0071] The high-pressure separation tank is mainly used to separate the gas-liquid two phases, and the low-pressure flash tank is mainly used to separate the heavy components such as acid, acetic acid and water.

[0072] High-pressure scrubbers are mainly used to separate methyl ester and water from light components such as methanol, methyl ester, methyl iodide and water.

[0073] The low-temperature washing tower is mainly used to recover the iodine in the product as much as possible to meet the environmental impact assessment emission standards, unreacted methyl ester, methanol in the product, and methyl iodide reaction reactor.

[0074] The deweighting tower is mainly used to separate the corresponding acid and acetic acid from acetic acid.

[0075] Preparation Example 1

[0076] Dissolve 1 mol of Ir precursor (IrCl3 or H2IrO4) and 2 mol of Ru precursor (RuCl3) in a 0.5 mol / L dilute hydrochloric acid solution, add 19 kg of activated carbon support, dry at 90°C until free-flowing, and then dry at 120°C. Calcinate at 400°C under N2 for 4 hours. Then switch to H2 for in-situ reduction at 400°C for 2 hours. Then, use CO2 to bubble CH3I from the device container through a bubbling device, treat at 240°C for 2-5 hours, and then cool to room temperature to obtain the Ir-Ru / AC catalyst.

[0077] The catalysts of other examples were prepared by referring to the method of Preparation Example 1.

[0078] Example 1

[0079] Catalyst: Ir / AC, Ir loading 1.0 wt.%.

[0080] Raw materials: methyl acetate + CO + H2 + water

[0081] Reactor type: fixed bed reactor

[0082] Material: Zirconium 702

[0083] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), H2O / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio);

[0084] Example 2

[0085] Catalyst: Ir-Ru / AC (catalyst obtained in Preparation Example 1), Ir loading amount 1.0 wt.%, Ru:Ir=2 (molar ratio).

[0086] Raw materials: methyl acetate + CO + H2 + water

[0087] Reactor type: fixed bed reactor

[0088] Material: Zirconium 702

[0089] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), H2O / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio);

[0090] Among them, the HAADF-STEM image of the catalyst is as follows Figure 1 As shown by Figure 1 It can be seen that Ir and Ru are dispersed on the support surface at the single-atom level.

[0091] Example 3

[0092] Catalyst: Ir-Li / AC, Ir loading 1.0 wt.%, Li:Ir=5 (molar ratio).

[0093] Raw materials: methyl acetate + CO + H2 + water

[0094] Reactor type: fixed bed reactor

[0095] Material: Zirconium 702

[0096] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1, CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1);

[0097] Example 4

[0098] Catalyst: Ir-Ru-Li / AC, Ir loading 1.0 wt.%, Ru:Ir=2 (molar ratio), Li:Ir=5 (molar ratio).

[0099] Raw materials: methyl acetate + CO + H2 + water

[0100] Reactor type: fixed bed reactor

[0101] Material: Zirconium 702

[0102] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), H2O / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio);

[0103] Example 5

[0104] Catalyst: Rh / AC, Rh loading 0.5 wt.%.

[0105] Raw materials: methyl acetate + CO + H2 + water

[0106] Reactor type: fixed bed reactor

[0107] Material: Zirconium 702

[0108] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), H2O / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio);

[0109] Example 6

[0110] Catalyst: Rh-Li / AC, Rh loading 0.5 wt.%, Li / Rh=5 (molar ratio).

[0111] Raw materials: methyl acetate + CO + H2 + water

[0112] Reactor type: fixed bed reactor

[0113] Material: Zirconium 702

[0114] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1 (molar ratio);

[0115] Example 7

[0116] Catalyst: Rh-Ru / AC, Rh loading 0.5 wt.%, Ru / Rh=2 (molar ratio).

[0117] Raw materials: methyl acetate + CO + H2 + water

[0118] Reactor type: fixed bed reactor

[0119] Material: Zirconium 702

[0120] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1 (molar ratio);

[0121] Example 8

[0122] Catalyst: Rh-Ru-Li / AC, Rh loading 0.5 wt.%, Ru / Rh=2 (molar ratio), Li / Rh=5 (molar ratio).

[0123] Reactor type: fixed bed reactor

[0124] Material: Zirconium 702

[0125] Raw materials: methyl acetate + CO + H2 + water

[0126] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1 (molar ratio);

[0127] Example 9

[0128] Catalyst: Rh / PIPs-N, Rh loading 0.5 wt.%.

[0129] Reactor type: fixed bed reactor

[0130] Material: Zirconium 702

[0131] Raw materials: methyl acetate + CO + H2 + water

[0132] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1 (molar ratio);

[0133] Example 10

[0134] Catalyst: Rh-Li / PIPs-N, Rh loading 0.5 wt.%, Li / Rh=5 (molar ratio).

[0135] Reactor type: fixed bed reactor

[0136] Material: Zirconium 702

[0137] Raw materials: methyl acetate + CO + H2 + water

[0138] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1 (molar ratio);

[0139] Example 11

[0140] Catalyst: Rh-Ru / PIPs-N, Rh loading 0.5 wt.%, Li / Rh=5 (molar ratio).

[0141] Raw materials: methyl acetate + CO + H2 + water

[0142] Reactor type: fixed bed reactor

[0143] Material: Zirconium 702

[0144] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1 (molar ratio);

[0145] Example 12

[0146] Catalyst: Rh-Ru-Li / PIPs-N, Rh loading 0.5 wt.%, Ru / Rh=2 (molar ratio), Li / Rh=5 (molar ratio).

[0147] Reactor type: fixed bed reactor

[0148] Material: Zirconium 702

[0149] Raw materials: methyl acetate + CO + H2 + water

[0150] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1 (molar ratio);

[0151] Example 13

[0152] Catalyst: Rh / PIPs-P, Rh loading 0.5wt.%

[0153] Reactor type: fixed bed reactor

[0154] Material: Zirconium 702

[0155] Raw materials: methyl acetate + CO + H2 + water

[0156] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1 (molar ratio);

[0157] Example 14

[0158] Catalyst: Rh-Li / PIPs-P, Rh loading 0.5 wt.%, Li / Rh=5 (molar ratio).

[0159] Reactor type: fixed bed reactor

[0160] Material: Zirconium 702

[0161] Raw materials: methyl acetate + CO + H2 + water

[0162] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1 (molar ratio);

[0163] Example 15

[0164] Catalyst: Rh-Ru / PIPs-P, Rh loading 0.5 wt.%, Ru / Rh=2 (molar ratio).

[0165] Reactor type: fixed bed reactor

[0166] Material: Zirconium 702

[0167] Raw materials: methyl acetate + CO + H2 + water

[0168] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1 (molar ratio);

[0169] Example 16

[0170] Catalyst: Rh-Ru-Li / PIPs-P, Rh loading 0.5 wt.%, Ru / Rh=2 (molar ratio), Li / Rh=5 (molar ratio).

[0171] Reactor type: fixed bed reactor

[0172] Material: Zirconium 702

[0173] Raw materials: methyl acetate + CO + H2 + water

[0174] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1 (molar ratio);

[0175] Example 17

[0176] Catalyst: Rh-Ru-Li / AC-N, Rh loading 0.5 wt.%, Ru / Rh=2 (molar ratio), Li / Rh=5 (molar ratio).

[0177] Reactor type: fixed bed reactor

[0178] Material: Zirconium 702

[0179] Raw materials: methyl acetate + CO + H2 + water

[0180] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1 (molar ratio);

[0181] Example 18

[0182] Catalyst: Rh-Ru-Li / AC-P, Rh loading 0.5 wt.%, Ru / Rh=2 (molar ratio), Li / Rh=5 (molar ratio).

[0183] Reactor type: fixed bed reactor

[0184] Material: Zirconium 702

[0185] Raw materials: methyl acetate + CO + H2 + water

[0186] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1 (molar ratio);

[0187] Example 19

[0188] Catalyst: Rh-Ru-Li / AC-S, Rh loading 0.5 wt.%, Ru / Rh=2 (molar ratio), Li / Rh=5 (molar ratio).

[0189] Reactor type: fixed bed reactor

[0190] Material: Zirconium 702

[0191] Raw materials: methyl acetate + CO + H2 + water

[0192] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1 , CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1 (molar ratio);

[0193] Example 20

[0194] Catalyst: Rh-Ru-K / AC, Rh loading 0.5 wt.%, Ru / Rh=2 (molar ratio), Li / Rh=5 (molar ratio).

[0195] Reactor type: fixed bed reactor

[0196] Material: Zirconium 702

[0197] Raw materials: methyl acetate + CO + H2 + water

[0198] Production conditions: methyl acetate reaction unit (235 ° C, 3.0 MPa, space velocity 4.0 h -1, CO / H2=10 (volume ratio), CO / methyl acetate=1 (molar ratio), methyl acetate / CH3I=6 (mass ratio), methyl acetate / water=1 (molar ratio)).

[0199] Acetic acid was prepared using Example 1-20. The carbonylation activity and product acetic acid selectivity are shown in Table 1.

[0200] Table 1 Summary of results of metal-catalyzed conversion of methyl acetate to acetic acid

[0201]

[0202]

[0203] The calculation of TOF refers to the molar ratio of CO converted per unit time to the molar ratio of Rh or Ir in the catalyst.

[0204] Conversion rate of methyl acetate = 100 - number of moles of methyl acetate in the product / number of moles of methyl acetate in the reactants * 100%

[0205] Acetic acid selectivity = moles of acetic acid in the product / (moles of acetic acid + acetaldehyde + methanol + dimethyl ether + propionic acid in the product) * 100%;

[0206] The results show that:

[0207] The results of Examples 1-20 indicate that, under the action of Rh, Ir, Ru, and Li co-catalysts, acetic acid can be prepared from methyl acetate, CO, and water in a single step with high activity and high selectivity.

[0208] The above descriptions are merely a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, they are not intended to limit the present application. Any technical personnel familiar with the present profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing acetic acid by catalysis of methyl acetate, characterized in that: In a reaction system containing a catalyst, methyl acetate is contacted with carbon monoxide and water to react to produce acetic acid; The catalyst contains an active element M, and the active element M is Rh and / or Ir.

2. The method according to claim 1, characterized in that The catalyst is a homogeneous catalyst and / or a supported heterogeneous catalyst; In the catalyst, the geometric molecular structure of the active element M is [M(CO) x I y ] δ- , wherein M is at least one of Rh and Ir; 0≤x≤2, 0≤y≤4, 0≤δ≤2.

3. The method according to claim 2, characterized in that When the catalyst is a supported heterogeneous catalyst, it also includes a carrier; The carrier is an inorganic carbon carrier and / or a porous organic carbon carrier; The inorganic carbon carrier is at least one of coconut shell activated carbon and apricot shell activated carbon, and the surface is modified with O functional groups; The porous organic carbon support is at least one of carbon-based supports containing N, O, P, and S functional groups; Preferably, in the supported heterogeneous catalyst, the mass loading of the active element M is 0.1 to 2.0 wt%; Preferably, when the support is an inorganic carbon support, the active element M is anchored by interacting with the N, O, P, and S functional groups on the support surface in the form of coordination bonds; Preferably, when the support is a porous organic carbon support, the support surface contains organic functional groups and / or inorganic functional groups; Wherein, the organic functional group is at least one of N, O, P, and S organic functional groups containing lone pair electrons; The inorganic functional group is [N] + 、[P] + At least one of the inorganic functional groups of the structure; The active element M interacts and anchors with the carrier in one of the ionic bond, ionic bond and coordination bond multiple coordination forms.

4. The method according to claim 2, characterized in that In the catalyst, the precursor of the active element M is selected from at least one of a simple substance containing the M element, chloride, bromide, iodide, carbonyl chloride, carbonyl bromide, carbonyl iodide, acetic acid compound, triphenylphosphine coordination compound, and carbonyl chloride compound.

5. The method according to claim 1, wherein The catalyst further includes a promoter element I, wherein the promoter element I is at least one of Li, Na, and K; In the catalyst, the molar ratio of the auxiliary element I to the active element is 0.1 to 10:1; The precursor of the auxiliary element I is selected from one of an iodide salt or an acetate containing the auxiliary element I; Preferably, the catalyst further comprises a promoter element II, and the promoter element II is at least one of Ru, Mn, and La; In the catalyst, the molar ratio of the auxiliary element II to the active element is 1 to 5:

1.

6. The method according to claim 1, characterized in that The reaction system further includes a co-catalyst; The co-catalyst is methyl iodide; The mass of the co-catalyst is 5% to 20% of the mass of the methyl acetate.

7. The method according to claim 1, characterized in that The reaction system further includes hydrogen; The volume content of the hydrogen is 2% to 10% of the volume of CO.

8. The method according to claim 1, characterized in that In the reaction system, the mass space velocity of methyl acetate is 2 to 6 h -1 ; The molar ratio of carbon monoxide to methyl acetate is 0.5 to 2; The mass of the water is 5% to 30% of methyl acetate; Preferably, when the catalyst is a homogeneous catalyst, the concentration of methyl acetate is 10 to 10000 ppm; Preferably, the reaction pressure is 1 to 5 MPa; The reaction time is 150-250°C.

9. A process device for preparing acetic acid by the method according to any one of claims 1 to 8, characterized in that: The process device comprises: The process device comprises a reaction unit and a separation unit connected in sequence; The separation unit includes a high-pressure separation tank, a high-pressure washing tower, a low-pressure flash tank, a low-temperature washing tower, and a de-weighting tower, wherein the top outlet I of the high-pressure separation tank is connected to the high-pressure washing tower, and the bottom outlet I of the high-pressure separation tank is connected to the low-pressure flash tank; the top outlet II and the bottom outlet II of the high-pressure washing tower are respectively connected to the reaction unit; the top outlet III of the low-pressure flash tank is connected to the low-temperature washing tower, and the bottom outlet III of the low-pressure flash tank is connected to the de-weighting tower; the top outlet IV and the bottom outlet IV of the low-temperature washing tower are respectively connected to the reaction unit, and are connected to a discharge port for venting gas; the de-weighting tower is provided with a top outlet V and a bottom outlet V; The high-pressure separation tank is connected to the reaction unit; The reaction unit consists of one reactor or two reactors connected in series.

10. The process device according to claim 9, characterized in that: The reactor is at least one of a tank reactor, a bubble column reactor, and a fixed bed reactor; The material of the reactor is one of C276 and Zr704.

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