CN115304483A - Production process for preparing dimethyl carbonate from synthesis gas - Google Patents

Production process for preparing dimethyl carbonate from synthesis gas Download PDF

Info

Publication number
CN115304483A
CN115304483A CN202211100514.5A CN202211100514A CN115304483A CN 115304483 A CN115304483 A CN 115304483A CN 202211100514 A CN202211100514 A CN 202211100514A CN 115304483 A CN115304483 A CN 115304483A
Authority
CN
China
Prior art keywords
dmc
gas
reactor
dimethyl carbonate
catalyst
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202211100514.5A
Other languages
Chinese (zh)
Inventor
陈高世
毛建忠
伊宝富
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to CN202211100514.5A priority Critical patent/CN115304483A/en
Publication of CN115304483A publication Critical patent/CN115304483A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C68/00—Preparation of esters of carbonic or haloformic acids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
    • B01J23/8926—Copper and noble metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J29/00—Catalysts comprising molecular sieves
    • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
    • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
    • B01J29/08—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y
    • B01J29/10—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y containing iron group metals, noble metals or copper
    • B01J29/14—Iron group metals or copper
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
    • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
    • B01J31/0234—Nitrogen-, phosphorus-, arsenic- or antimony-containing compounds
    • B01J31/0271—Nitrogen-, phosphorus-, arsenic- or antimony-containing compounds also containing elements or functional groups covered by B01J31/0201 - B01J31/0231
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/61—Surface area
    • B01J35/617—500-1000 m2/g
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/63—Pore volume
    • B01J35/633—Pore volume less than 0.5 ml/g
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C201/00—Preparation of esters of nitric or nitrous acid or of compounds containing nitro or nitroso groups bound to a carbon skeleton
    • C07C201/04—Preparation of esters of nitrous acid
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C203/00—Esters of nitric or nitrous acid
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
    • C07C69/96—Esters of carbonic or haloformic acids
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F9/00—Compounds containing elements of Groups 5 or 15 of the Periodic Table
    • C07F9/02—Phosphorus compounds
    • C07F9/28—Phosphorus compounds with one or more P—C bonds
    • C07F9/30—Phosphinic acids [R2P(=O)(OH)]; Thiophosphinic acids ; [R2P(=X1)(X2H) (X1, X2 are each independently O, S or Se)]
    • C07F9/36—Amides thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
    • B01J2229/10—After treatment, characterised by the effect to be obtained
    • B01J2229/18—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself
    • B01J2229/186—After treatment, characterised by the effect to be obtained to introduce other elements into or onto the molecular sieve itself not in framework positions

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Molecular Biology (AREA)
  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

The invention discloses a production process for preparing dimethyl carbonate from synthesis gas, belonging to the technical field of chemical production; the process method can improve the selectivity of the raw materials and the DMC space-time yield, and adopts a special structure aiming at the complexity of the esterification reaction, thereby eliminating potential safety hazards; the unique regeneration process of MN provides guarantee for the reaction of the system; the water and impurity removing device with independent intellectual property is adopted, the moisture generated in the esterification process is effectively solved, the coupling catalyst is protected, and the service life of the catalyst is prolonged.

Description

Production process for preparing dimethyl carbonate from synthesis gas
Technical Field
The invention belongs to the technical field of chemical production, and particularly relates to a production process for preparing dimethyl carbonate from synthesis gas.
Background
Dimethyl carbonate, an organic compound of formula C 3 H 6 O 3 The derivative is a chemical raw material with low toxicity, excellent environmental protection performance and wide application, is an important organic synthesis intermediate, contains functional groups such as carbonyl, methyl, methoxyl and the like in a molecular structure, has various reaction performances, and has the characteristics of safe and convenient use, less pollution, easy transportation and the like in production.
The main flow of the dimethyl carbonate synthesis process is as follows:
(1) Phosgene sodium alkoxide process
The reaction equation of the sodium methoxide method (also called a methanol chloroformate method) is as follows:
COCl 2 +2CH 3 ONa→2(CH 3 O) 2 CO+2NaCl
the method is a traditional process for producing DMC, and the process takes phosgene with high toxicity as a raw material, and has the problems of high toxicity, serious environmental pollution and the like. This process is not currently used except for the fact that some of the earlier built devices are in operation.
(2) Sodium chloromethane process
The method still uses sodium methoxide as a production raw material, and uses chloromethane to replace phosgene to produce DMC, and the specific reaction formula is as follows:
CH 3 ONa+CO 2 →NaOCOOCH 3
NaOCOOCH 3 +CH 3 Cl→(CH 3 O) 2 CO+NaCl
the method does not use phosgene, but the adopted chloromethane and the selenium-containing catalyst still have toxicity; in addition, in the production process of the method, a large amount of NaOH can be produced as a byproduct, so that the DMC product is rapidly hydrolyzed, the yield of DMC is greatly reduced, and the application of the method is limited.
(3) Liquid phase oxidative carbonylation process
As a non-phosgene method for producing DMC, the industrial production of DMC prepared by methanol liquid-phase oxidative carbonylation method was realized for the first time in 1983 by ENI chemical synthesis company in Italy, and the production scale reaches 12kt/a at present.
The reaction equation of the ENI liquid-phase oxidation carbonylation method is as follows:
2CH 3 OH+1/2O1+1CuCl→2Cu(OCH 3 )Cl+H 2 O
CO+2Cu(OCH 3 )Cl→(CH 3 O)CO+2CuCl
the method uses cuprous chloride as catalyst, and directly adds it into excessive methanol, and then introduces CO and O 2 . The reaction is carried out in two steps in two stirred tank reactors connected in series. Methanol is both a reactant and a solvent. The reaction temperature is controlled between 120 and 130 ℃, and the pressure is 2.0 to 3.0MPa. The process flow comprises an oxidative carbonylation section and a DMC separation and recovery section. The mixture of DMC and methanol was separated using chlorobenzene as extractant.
The method has the advantages of high yield, single-pass conversion rate of 32 percent and selectivity of more than 98 percent based on methanol. The weakness is that the production device adopts a kettle type reactor, and the adverse factors that the selectivity of CO to DMC is a time decreasing function, the hydrolysis of the catalyst and the like cannot be overcome. In order to keep the oxygen content in the off-gas out of the explosive range, the oxidation flow rate must be effectively controlled to extend the reaction time per pot, which inevitably results in CO 2 The yield of (A) is increased and the water produced in the reaction system cannot be removed in time, and under the action of these adverse factors, the selectivity of the reaction (in terms of CO) becomes very unstable, and the catalyst life is shortened and the corrosiveness to equipment is increased.
(4) Ester interchange method
The ester exchange method is firstly developed by Texaco company in 1992 in the United states, and the process is to prepare ethylene carbonate by ethylene oxide and CO2, and then carry out ester exchange reaction with methanol to synthesize DMC, and simultaneously by-product ethylene glycol; through research and development for more than ten years in China, the production technology of ethylene carbonate and propylene carbonate is mature, and the production technology of synthesizing dimethyl carbonate by using an ester exchange method is also mature. The best method currently used is the transesterification process using carbon dioxide, methanol and propylene oxide as starting materials.
The method has the advantages that: the method has the advantages of simple and easy process, high yield, low corrosivity, mild reaction conditions, non-toxic reaction process and no pollution to the environment. But the price of the raw material propylene oxide/ethylene oxide is high and is influenced by the price of petroleum, the purity of the by-product propylene glycol/ethylene glycol is low, the market selling is poor, and the phenomenon that the product and the raw material are hung upside down exists once when the dimethyl carbonate is prepared by the ester exchange method. In addition, the reaction conversion rate is low and the production energy consumption is high due to the limitation of thermodynamic equilibrium.
Disclosure of Invention
The invention discloses a technical scheme for synthesizing dimethyl carbonate by CO. The reaction method is characterized in that CO does not synthesize dimethyl carbonate under oxygen atmosphere, so the selectivity of CO is up to 90 percent, the DMC space-time yield is higher and can reach 450-550 g/l-cat.
The technique adopted by the invention is as follows
A production process for preparing dimethyl carbonate from synthesis gas comprises the following steps: (1) Methyl Nitrite (MN) synthesis step; and (2) a dimethyl carbonate (DMC) synthesis step.
Preferably, the Methyl Nitrite (MN) synthesis step: mixing fresh oxygen, NO and NO-containing circulating gas from a dimethyl carbonate (DMC) synthesis process through a static mixer, then entering the bottom of a methyl nitrite reactor, and carrying out countercurrent contact on the mixed gas and methanol sprayed from the upper part of the reactor to generate methyl nitrite and water; methanol: NO: o is 2 Molar ratio =8 to 11:4 to 5:0.8 to 1.2 of N 2 Volume of NO and O 2 5 to 7 times of the sum of the components, the reaction pressure is 0.1 to 0.5MPa, the reaction temperature is 25 to 80 ℃, and the reaction time is 20 to 40min; cooling the gas at the outlet of the top of the reactor to a certain temperature, then sending the gas into a dimethyl carbonate unit, introducing the alcohol-containing wastewater discharged from the bottom of the reactor into a methanol recovery tower to recover methanol, and introducing the acid-containing wastewater at the bottom of the recovery tower into a wastewater treatment device.
Preferably, the dimethyl carbonate (DMC) synthesis step: the mixed gas containing MN from the synthesis process of Methyl Nitrite (MN) is mixed with fresh CO raw gas, wherein the molar ratio of MN to CO = 1-4 (molar ratio) is preheated to 100-120 ℃ by a DMC preheater, the mixture enters a DMC reactor, a catalyst with the volume of 10-30% of that of the DMC reactor is added into the reactor, the generated reactant enters the DMC preheater for heat exchange and cooling, then enters a DMC condenser for condensation at 25-60 ℃, the product is separated by a gas-liquid separator, 5-20% of a gas-phase product is sent to a tail gas treatment system, the rest is recycled to a methyl nitrite unit, and a liquid-phase product enters a DMC rectifying tower to produce a high-purity DMC product.
Preferably, the space velocity of the methyl nitrite is 1600-3200h -1 The space velocity of the carbon monoxide is 800-1600h -1 。
Preferably, the preheating temperature of the preheater is 110-165 ℃.
Preferably, the DMC reactor reaction pressure is controlled in the range of 0.1 to 1MPa.
Preferably, in the dimethyl carbonate (DMC) synthesis step, the top gas from the ester absorption tower is cooled by a condenser, then enters a gas-liquid separation tank, the separated non-condensable gas (mainly NO) is subjected to an esterification step, and the liquid is mixed with the liquid-phase working medium from the bottom of the absorption tower and then is pumped to the esterification step.
Preferably, the dimethyl carbonate synthesis catalyst consists of a main catalyst and a cocatalyst, wherein the main catalyst is Pd/Cu/Al 2 O 3 Pd in the catalyst 0.1-2.5 wt%, cu in the catalyst 0.01-1.5 wt%, FAU type molecular sieve with average grain size of 0.1-4 micron and molecular sieve pore volume of 0.21-0.37 cm 3 (g) the specific surface area of the molecular sieve is 750-950 m 2 /g。
Preferably, the molar ratio of the cocatalyst to the procatalyst is from 1:5 to 1: 15.
Preferably, the preparation method of the cocatalyst comprises the following steps:
s1: adding 10-30 parts of 2-mercapto-6-aminopyridine, 100-120 parts of DMF,3-7 parts of diphenylphosphine chloride and 2-5 parts of AlCl into a stirring kettle 3 Reacting for 0.5-1.5h at 50-60 ℃;
s2: then adding 2-5 parts of potassium tert-butoxide, 10-15 parts of copper acrylate, 0.2-1.6 parts of ammonium persulfate, reacting for 0.5-2.5h at 40-50 ℃, and removing DMF by reduced pressure distillation to obtain the cocatalyst.
Compared with the prior art, the invention has the beneficial effects that:
the invention ensures that CO does not react in the oxygen atmosphere, so the selectivity of CO is up to more than 90 percent, the DMC space-time yield is higher and can reach 450-550 g/l-cat.h; aiming at the complexity of the esterification reaction, a special structure is designed, so that potential safety hazards are eliminated; the unique regeneration process of MN provides guarantee for the reaction of the system; the device for removing water and impurities with independent intellectual property rights is adopted, so that the moisture generated in the esterification process is effectively solved, the coupling catalyst is protected, and the service life of the catalyst is prolonged.
The 2-mercapto-6-aminopyridine and diphenylphosphonyl chloride generate amide, and the mercapto group of the amide and copper acrylate undergo addition reaction to obtain the cocatalyst.
Drawings
FIG. 1 is a synthesis process diagram.
Detailed Description
The present invention will be described in further detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.
Example 1
A production process for preparing dimethyl carbonate from synthesis gas specifically comprises the following steps:
(1) A Methyl Nitrite (MN) synthesis step;
mixing fresh oxygen, NO and circulating gas containing NO from a dimethyl carbonate (DMC) synthesis process through a static mixer, then entering the bottom of a methyl nitrite reactor, and carrying out countercurrent contact with methanol sprayed from the upper part of the reactor to generate methyl nitrite and water; methanol: NO: o is 2 Molar ratio =8:4:0.8, N 2 Volume of NO and O 2 5 times of the sum, the reaction pressure is 0.1MPa, the reaction temperature is 25 ℃, and the reaction time is 40min; cooling the gas at the outlet of the top of the reactor to a certain temperature, sending the gas into a dimethyl carbonate unit, introducing alcohol-containing wastewater discharged from the bottom of the reactor into a methanol recovery tower to recover methanol, and treating the acid-containing wastewater at the bottom of the recovery tower to obtain wastewaterProvided is a device.
(2) Dimethyl carbonate (DMC) synthesis process.
The mixed gas containing MN from the synthesis process of Methyl Nitrite (MN) is mixed with fresh CO raw gas, wherein the molar ratio of MN to CO =1 is preheated to 100 ℃ by a DMC preheater, the mixed gas enters a DMC reactor, a catalyst with the volume of 10 percent of that of the DMC reactor is added into the reactor, the generated reactant enters a DMC preheater for heat exchange and cooling, the condensed reactant enters a DMC condenser for condensation for 25 ℃, the condensed reactant is separated by a gas-liquid separator, 5 percent of gas phase products are removed and sent to a tail gas treatment system, the rest is recycled to a methyl nitrite unit for recycling, and liquid phase products enter a DMC rectifying tower for producing high-purity DMC products.
The airspeed of the methyl nitrite is 1600h -1 The space velocity of carbon monoxide is 800h -1 。
The preheating temperature of the preheater is 110 ℃.
The DMC reactor reaction pressure was controlled at 0.1MPa.
And in the dimethyl carbonate (DMC) synthesis process, the tower top gas from the ester absorption tower is cooled by a condenser and then enters a gas-liquid separation tank, the separated noncondensable gas (mainly NO) is subjected to an esterification process, and the liquid is mixed with the liquid phase working medium from the bottom of the absorption tower and then is pumped to the esterification process.
The dimethyl carbonate synthesis catalyst consists of a main catalyst and a cocatalyst, wherein the main catalyst is Pd/Cu/Al 2 O 3 Pd accounting for 0.1wt% of the catalyst, cu accounting for 1.5wt% of the catalyst, the molecular sieve is an FAU type molecular sieve, the average particle size is 4 micrometers, and the sieve pore volume of the molecular sieve is 0.37cm 3 Per g, the specific surface area of the molecular sieve is 950m 2 /g。。
The molar ratio of the cocatalyst to the main catalyst is 1: 5.
The preparation method of the cocatalyst comprises the following steps:
s1: to a stirred tank were added 10kg of 2-mercapto-6-aminopyridine, 100kg of DMF,3kg of diphenylphosphonyl chloride, 2kg of AlCl 3 Reacting for 1.5h at 50 ℃;
s2: then 2kg of potassium tert-butoxide, 10kg of copper acrylate and 0.2kg of ammonium persulfate are added to react for 2.5h at 40 ℃, and DMF is removed by reduced pressure distillation to obtain the cocatalyst.
Example 2
A production process for preparing dimethyl carbonate from synthesis gas specifically comprises the following steps:
(1) A Methyl Nitrite (MN) synthesis step;
mixing fresh oxygen, NO and circulating gas containing NO from a dimethyl carbonate (DMC) synthesis process through a static mixer, then entering the bottom of a methyl nitrite reactor, and carrying out countercurrent contact with methanol sprayed from the upper part of the reactor to generate methyl nitrite and water; methanol: NO: o is 2 Molar ratio =9:49:0.89, N 2 Volume of NO and O 2 5 times of the sum, the reaction pressure is 0.3MPa, the reaction temperature is 35 ℃, and the reaction time is 20min; cooling the gas at the outlet of the top of the reactor to a certain temperature, then sending the gas into a dimethyl carbonate unit, introducing the alcohol-containing wastewater discharged from the bottom of the reactor into a methanol recovery tower to recover methanol, and introducing the acid-containing wastewater at the bottom of the recovery tower into a wastewater treatment device.
(2) Dimethyl carbonate (DMC) synthesis process.
The mixed gas containing MN from the synthesis process of Methyl Nitrite (MN) is mixed with fresh CO raw gas, wherein the molar ratio of MN to CO =2 is preheated to 100 ℃ by a DMC preheater, the mixed gas enters a DMC reactor, a catalyst with the volume of 15 percent of that of the DMC reactor is added into the reactor, the generated reactant enters a DMC preheater for heat exchange and cooling, the condensed reactant enters a DMC condenser for condensation at 45 ℃, the condensed reactant is separated by a gas-liquid separator, 10 percent of gas phase products are removed and sent to a tail gas treatment system, the rest is recycled to a methyl nitrite unit for recycling, and liquid phase products enter a DMC rectifying tower for producing high-purity DMC products.
The space velocity of the methyl nitrite is 2400h -1 The space velocity of carbon monoxide is 1200h -1 。
The preheating temperature of the preheater is 125 ℃.
The DMC reactor reaction pressure was controlled at 0.4MPa.
In the dimethyl carbonate (DMC) synthesis process, the tower top gas from an ester absorption tower enters a gas-liquid separation tank after being cooled by a condenser, the separated noncondensable gas (mainly NO) is subjected to an esterification process, and the liquid is mixed with the liquid phase working medium from the bottom of the absorption tower and then is pumped to the esterification process.
The dimethyl carbonate synthesis catalyst consists of a main catalyst and a cocatalyst, wherein the main catalyst is Pd/Cu/Al 2 O 3 Pd accounting for 0.9wt% of the catalyst, cu accounting for 1.0wt% of the catalyst, the molecular sieve is an FAU type molecular sieve, the average particle size is 2 microns, and the pore volume of the molecular sieve is 0.32m 3 (g) the specific surface area of the molecular sieve is 850m 2 /g。。
The molar ratio of the cocatalyst to the main catalyst is 1: 8.
The preparation method of the cocatalyst comprises the following steps:
s1: 1691g of 2-mercapto-6-aminopyridine, 100kg of DMF,4kg of diphenylphosphonyl chloride and 3kg of AlCl were added into a stirred tank 3 Reacting for 1.0h at 50 ℃;
s2: then 3kg of potassium tert-butoxide, 12kg of copper acrylate and 0.6kg of ammonium persulfate are added to react for 1.0h at the temperature of 40 ℃, and DMF is removed by reduced pressure distillation to obtain the cocatalyst.
Example 3
A production process for preparing dimethyl carbonate from synthesis gas specifically comprises the following steps:
(1) A Methyl Nitrite (MN) synthesis step;
mixing fresh oxygen, NO and circulating gas containing NO from a dimethyl carbonate (DMC) synthesis process through a static mixer, then entering the bottom of a methyl nitrite reactor, and carrying out countercurrent contact with methanol sprayed from the upper part of the reactor to generate methyl nitrite and water; methanol: NO: o is 2 Molar ratio =10:5:0.8, N 2 Volume of NO and O 2 6 times of the sum, the reaction pressure is 0.4MPa, the reaction temperature is 65 ℃, and the reaction time is 30min; cooling the gas at the outlet of the top of the reactor to a certain temperature, then sending the gas into a dimethyl carbonate unit, introducing the alcohol-containing wastewater discharged from the bottom of the reactor into a methanol recovery tower to recover methanol, and introducing the acid-containing wastewater at the bottom of the recovery tower into a wastewater treatment device.
(2) Dimethyl carbonate (DMC) synthesis process.
The mixed gas containing MN from the synthesis process of Methyl Nitrite (MN) is mixed with fresh CO raw gas, wherein the molar ratio of MN to CO =3 is preheated to 110 ℃ by a DMC preheater, the mixed gas enters a DMC reactor, a catalyst with the volume of 20% of that of the DMC reactor is added into the reactor, the generated reactant enters a DMC preheater for heat exchange and cooling, the condensed reactant enters a DMC condenser for condensation at 45 ℃, the condensed reactant is separated by a gas-liquid separator, 15% of a gas-phase product is removed and sent to a tail gas treatment system, the rest is recycled to a methyl nitrite unit for recycling, and a liquid-phase product enters a DMC rectifying tower for producing a high-purity DMC product.
The space velocity of the methyl nitrite is 2800h -1 The space velocity of carbon monoxide is 1400h -1 。
The preheating temperature of the preheater is 145 ℃.
The DMC reactor reaction pressure was controlled at 0.8MPa.
And in the dimethyl carbonate (DMC) synthesis process, the tower top gas from the ester absorption tower is cooled by a condenser and then enters a gas-liquid separation tank, the separated noncondensable gas (mainly NO) is subjected to an esterification process, and the liquid is mixed with the liquid phase working medium from the bottom of the absorption tower and then is pumped to the esterification process.
The dimethyl carbonate synthesis catalyst consists of a main catalyst and a cocatalyst, wherein the main catalyst is Pd/Cu/Al 2 O 3 Pd accounting for 1.7wt% of the catalyst and Cu accounting for 0.5wt% of the catalyst, wherein the molecular sieve is an FAU type molecular sieve with an average particle size of 1 micron and a molecular sieve pore volume of 0.26cm 3 Per g, the specific surface area of the molecular sieve is 800m 2 /g。
The molar ratio of the cocatalyst to the main catalyst is 1: 12.
The preparation method of the cocatalyst comprises the following steps:
s1: 24kg of 2-mercapto-6-aminopyridine, 120kg of DMF,6kg of diphenylphosphonyl chloride and 4kg of AlCl were added to a stirred tank 3 Reacting for 0.5h at the temperature of 60 ℃,
s2: then 4kg of potassium tert-butoxide, 15kg of copper acrylate and 1.2kg of ammonium persulfate are added to react for 0.5h at 50 ℃, and DMF is removed by reduced pressure distillation to obtain the cocatalyst.
Example 4
A production process for preparing dimethyl carbonate from synthesis gas specifically comprises the following steps:
(1) A Methyl Nitrite (MN) synthesis step;
mixing fresh oxygen, NO and circulating gas containing NO from a dimethyl carbonate (DMC) synthesis process through a static mixer, then entering the bottom of a methyl nitrite reactor, and carrying out countercurrent contact with methanol sprayed from the upper part of the reactor to generate methyl nitrite and water; methanol: NO: o is 2 Molar ratio =11:5:1.2, N 2 Volume of NO and O 2 7 times of the sum, the reaction pressure is 0.5MPa, the reaction temperature is 80 ℃, and the reaction time is 20min; cooling the gas at the outlet of the top of the reactor to a certain temperature, then sending the gas into a dimethyl carbonate unit, introducing the alcohol-containing wastewater discharged from the bottom of the reactor into a methanol recovery tower to recover methanol, and introducing the acid-containing wastewater at the bottom of the recovery tower into a wastewater treatment device.
(2) Dimethyl carbonate (DMC) synthesis process.
The mixed gas containing MN from the synthesis process of Methyl Nitrite (MN) is mixed with fresh CO raw gas, wherein the molar ratio of MN to CO =4 is preheated to 120 ℃ by a DMC preheater, the mixed gas enters a DMC reactor, a catalyst with the volume of 30% of that of the DMC reactor is added into the reactor, the generated reactant enters a DMC preheater for heat exchange and cooling, the condensed reactant enters a DMC condenser for condensation at 60 ℃, the condensed reactant is separated by a gas-liquid separator, 20% of a gas-phase product is removed and sent to a tail gas treatment system, the rest is recycled to a methyl nitrite unit for recycling, and a liquid-phase product enters a DMC rectifying tower for producing a high-purity DMC product.
The airspeed of the methyl nitrite is 3200h -1 The space velocity of carbon monoxide is 1600h -1 。
The preheating temperature of the preheater is 165 ℃.
The DMC reactor reaction pressure was controlled at 1MPa.
In the dimethyl carbonate (DMC) synthesis process, the tower top gas from an ester absorption tower enters a gas-liquid separation tank after being cooled by a condenser, the separated noncondensable gas (mainly NO) is subjected to an esterification process, and the liquid is mixed with the liquid phase working medium from the bottom of the absorption tower and then is pumped to the esterification process.
The dimethyl carbonate synthesis catalyst consists of a main catalyst and a cocatalyst, wherein the main catalyst is Pd/Cu/Al 2 O 3 Pd accounts for 2.5wt% of the catalyst, and Cu accounts for 0wt% of the catalyst.1wt% of FAU type molecular sieve with average particle diameter of 0.1 micrometer and molecular sieve pore volume of 0.21cm 3 (ii)/g, specific surface area of molecular sieve 750m 2 /g。
The molar ratio of the cocatalyst to the main catalyst is 1: 15.
The preparation method of the cocatalyst comprises the following steps:
s1: 30kg of 2-mercapto-6-aminopyridine, 120kg of DMF,7kg of diphenylphosphonyl chloride and 5kg of AlCl were added to a stirred tank 3 Reacting for 1.5h at the temperature of 60 ℃,
s2: then 5kg of potassium tert-butoxide, 15kg of copper acrylate and 1.6kg of ammonium persulfate are added to react for 2.5h at 50 ℃, and DMF is removed by reduced pressure distillation to obtain the cocatalyst.
Characterization and testing
The product was qualitatively and quantitatively analyzed using a gas chromatograph (FULI 9790 II) equipped with a hydrogen Flame Ionization Detector (FID) and a SE-54 capillary column (50 m.times.0.32 mm.times.1 um).
Test results
Selectivity to CO% DMC space-time yield g/l-cat.h
Example 1 90.3 453
Example 2 90.7 487
Example 3 91.0 512
Example 4 91.2 551

Claims (10)

1. A production process for preparing dimethyl carbonate from synthesis gas comprises the following steps: (1) Methyl Nitrite (MN) synthesis step; and (2) a dimethyl carbonate (DMC) synthesis step.
2. The method of claim 1, wherein: the Methyl Nitrite (MN) synthesis step: mixing fresh oxygen, NO and circulating gas containing NO from a dimethyl carbonate (DMC) synthesis process through a static mixer, then entering the bottom of a methyl nitrite reactor, and carrying out countercurrent contact with methanol sprayed from the upper part of the reactor to generate methyl nitrite and water; methanol: NO: o is 2 Molar ratio =8 to 11:4 to 5:0.8 to 1.2 of N 2 Volume of NO and O 2 5 to 7 times of the sum of the components, the reaction pressure is 0.1 to 0.5MPa, the reaction temperature is 25 to 80 ℃, and the reaction time is 20 to 40min; cooling the gas at the outlet of the top of the reactor to a certain temperature, then sending the gas into a dimethyl carbonate unit, introducing the alcohol-containing wastewater discharged from the bottom of the reactor into a methanol recovery tower to recover methanol, and introducing the acid-containing wastewater at the bottom of the recovery tower into a wastewater treatment device.
3. The method of claim 1, wherein: the dimethyl carbonate (DMC) synthesis procedure: the mixed gas containing MN from the synthesis process of Methyl Nitrite (MN) is mixed with fresh CO raw gas, wherein the molar ratio of MN to CO = 1-4 (molar ratio) is preheated to 100-120 ℃ by a DMC preheater, the mixture enters a DMC reactor, a catalyst with the volume of 10-30% of that of the DMC reactor is added into the reactor, the generated reactant enters the DMC preheater for heat exchange and cooling, then enters a DMC condenser for condensation at 25-60 ℃, the product is separated by a gas-liquid separator, 5-20% of a gas-phase product is sent to a tail gas treatment system, the rest is recycled to a methyl nitrite unit, and a liquid-phase product enters a DMC rectifying tower to produce a high-purity DMC product.
4. The method of claim 3, wherein: the airspeed of the methyl nitrite is 1600-3200h -1 The space velocity of the carbon monoxide is 800-1600h -1 。
5. The method of claim 3, wherein: the preheating temperature of the preheater is 110-165 ℃.
6. The method of claim 3, wherein: the DMC reactor reaction pressure is controlled between 0.1 and 1MPa.
7. The method of claim 3, wherein: and in the dimethyl carbonate (DMC) synthesis process, the tower top gas from the ester absorption tower is cooled by a condenser and then enters a gas-liquid separation tank, the separated noncondensable gas (mainly NO) is subjected to an esterification process, and the liquid is mixed with the liquid phase working medium from the bottom of the absorption tower and then is pumped to the esterification process.
8. The method of claim 3, wherein: the dimethyl carbonate synthesis catalyst consists of a main catalyst and a cocatalyst, wherein the main catalyst is Pd/Cu/Al 2 O 3 Pd in the catalyst 0.1-2.5 wt%, cu in the catalyst 0.01-1.5 wt%, FAU type molecular sieve with average grain size of 0.1-4 micron and molecular sieve pore volume of 0.21-0.37 cm 3 G, the specific surface area of the molecular sieve is 750-950 m 2 /g。
9. The method of claim 8, wherein: the molar ratio of the cocatalyst to the main catalyst is 1:5 to 1: 15.
10. The method of claim 8, wherein: the preparation method of the cocatalyst comprises the following steps:
s1: adding 10-30 parts of 2-mercapto-6-aminopyridine, 100-120 parts of DMF (dimethyl formamide), 3-7 parts of diphenylphosphonic chloride and 2-5 parts of AlCl into a stirring kettle 3 Reacting for 0.5-1.5h at 50-60 ℃;
s2: then adding 2-5 parts of potassium tert-butoxide, 10-15 parts of copper acrylate, 0.2-1.6 parts of ammonium persulfate, reacting for 0.5-2.5h at 40-50 ℃, and removing DMF by reduced pressure distillation to obtain the cocatalyst.
CN202211100514.5A 2022-09-08 2022-09-08 Production process for preparing dimethyl carbonate from synthesis gas Pending CN115304483A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202211100514.5A CN115304483A (en) 2022-09-08 2022-09-08 Production process for preparing dimethyl carbonate from synthesis gas

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211100514.5A CN115304483A (en) 2022-09-08 2022-09-08 Production process for preparing dimethyl carbonate from synthesis gas

Publications (1)

Publication Number Publication Date
CN115304483A true CN115304483A (en) 2022-11-08

Family

ID=83865672

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202211100514.5A Pending CN115304483A (en) 2022-09-08 2022-09-08 Production process for preparing dimethyl carbonate from synthesis gas

Country Status (1)

Country Link
CN (1) CN115304483A (en)

Similar Documents

Publication Publication Date Title
KR930010407B1 (en) Process for production of dimethyl carbonate
CN104844556B (en) Method for continuously preparing vinylene carbonate by tubular reactor
WO2021078239A1 (en) Gas-liquid bubbling bed reactor, reaction system and method for synthesizing carbonate
CN108997085B (en) Method and system for recovering by-products in dimethyl oxalate synthesis process
CN100364956C (en) Method of distillation and ester exchange reaction for producing dimethyl carbonate and dihydroxyl alcohols
AU2015203732B2 (en) Method for producing dimethyl oxalate
CN111825568A (en) Synthesis method of perfluoroisobutyronitrile
EP0046598B1 (en) Process for continuously preparing a diester of oxalic acid
CN1227839A (en) Process for low-pressure synthesis of dimethyl carbonate by carbon monoxide
CN110922292B (en) Preparation method of chloromethane
CN114163333B (en) Method for synthesizing methyl ethyl carbonate in one step
CN111848444A (en) Synthesis method of perfluoroisobutyronitrile
US5631396A (en) Process for continuously producing dimethyl carbonate
CN106518675B (en) The method for producing dimethyl oxalate and by-product dimethyl carbonate
CN113816826A (en) Purification method of electronic-grade monofluoromethane
US5534648A (en) Process for continuously producing dimethyl carbonate
CN115304483A (en) Production process for preparing dimethyl carbonate from synthesis gas
CN108586243B (en) Method for indirectly synthesizing organic carbonate from carbon dioxide and organic amine
JP3358631B2 (en) Method for dehydrogenation of methanol
CN116265056A (en) Product separation refining device and method for preparing dimethyl carbonate by CO esterification
CN112028771A (en) Method and system for producing alkyl carbonate
CN219848214U (en) Recovery device for dimethyl carbonate as byproduct of dimethyl oxalate synthesis
CN1318384C (en) Polyphosphoric acid catalyzed dimethyl carbonate synthesizing process
CN111943927B (en) Method for preparing propylene (or ethylene) carbonate by continuous reaction injection
CA1055525A (en) Method for decomposing an aromatic aldehyde-hydrogen fluoride-boron trifluoride complex

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication