CN117482854A - Method and device for preparing polymethoxy dimethyl ether from paraformaldehyde - Google Patents
Method and device for preparing polymethoxy dimethyl ether from paraformaldehyde Download PDFInfo
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- CN117482854A CN117482854A CN202210879219.8A CN202210879219A CN117482854A CN 117482854 A CN117482854 A CN 117482854A CN 202210879219 A CN202210879219 A CN 202210879219A CN 117482854 A CN117482854 A CN 117482854A
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- methanol
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- dimethyl ether
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- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 title claims abstract description 94
- 229930040373 Paraformaldehyde Natural products 0.000 title claims abstract description 48
- 229920002866 paraformaldehyde Polymers 0.000 title claims abstract description 48
- 238000000034 method Methods 0.000 title claims abstract description 25
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 141
- 230000003197 catalytic effect Effects 0.000 claims abstract description 43
- 238000006243 chemical reaction Methods 0.000 claims abstract description 37
- 239000003054 catalyst Substances 0.000 claims abstract description 35
- NKDDWNXOKDWJAK-UHFFFAOYSA-N dimethoxymethane Chemical compound COCOC NKDDWNXOKDWJAK-UHFFFAOYSA-N 0.000 claims abstract description 33
- 150000002373 hemiacetals Chemical class 0.000 claims abstract description 32
- 238000010528 free radical solution polymerization reaction Methods 0.000 claims abstract description 28
- 239000007788 liquid Substances 0.000 claims abstract description 28
- 238000010438 heat treatment Methods 0.000 claims abstract description 14
- 238000006555 catalytic reaction Methods 0.000 claims abstract description 13
- 239000000463 material Substances 0.000 claims abstract description 12
- 238000002156 mixing Methods 0.000 claims abstract description 9
- 229920002521 macromolecule Polymers 0.000 claims abstract description 8
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 claims abstract description 6
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 claims abstract description 4
- 239000003729 cation exchange resin Substances 0.000 claims abstract description 4
- 239000002253 acid Substances 0.000 claims abstract 2
- 239000000203 mixture Substances 0.000 claims description 21
- 238000007599 discharging Methods 0.000 claims description 18
- 239000007787 solid Substances 0.000 claims description 13
- 239000011973 solid acid Substances 0.000 claims description 12
- 238000000926 separation method Methods 0.000 claims description 11
- 239000002994 raw material Substances 0.000 claims description 8
- 238000011084 recovery Methods 0.000 claims description 7
- 230000015572 biosynthetic process Effects 0.000 claims description 6
- 238000003786 synthesis reaction Methods 0.000 claims description 6
- 238000006266 etherification reaction Methods 0.000 claims description 3
- 230000004048 modification Effects 0.000 claims description 3
- 238000012986 modification Methods 0.000 claims description 3
- 238000000746 purification Methods 0.000 claims description 2
- 238000000066 reactive distillation Methods 0.000 claims description 2
- 239000002245 particle Substances 0.000 claims 1
- 239000000843 powder Substances 0.000 claims 1
- 230000002194 synthesizing effect Effects 0.000 abstract description 6
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 42
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 15
- 239000000945 filler Substances 0.000 description 13
- 239000000126 substance Substances 0.000 description 12
- 238000009835 boiling Methods 0.000 description 10
- 239000000047 product Substances 0.000 description 10
- 239000002283 diesel fuel Substances 0.000 description 9
- 238000011049 filling Methods 0.000 description 7
- 238000002360 preparation method Methods 0.000 description 7
- 239000002808 molecular sieve Substances 0.000 description 6
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 238000010992 reflux Methods 0.000 description 5
- 229910000323 aluminium silicate Inorganic materials 0.000 description 4
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 4
- TZIHFWKZFHZASV-UHFFFAOYSA-N methyl formate Chemical compound COC=O TZIHFWKZFHZASV-UHFFFAOYSA-N 0.000 description 4
- 238000007789 sealing Methods 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- BGJSXRVXTHVRSN-UHFFFAOYSA-N 1,3,5-trioxane Chemical group C1OCOCO1 BGJSXRVXTHVRSN-UHFFFAOYSA-N 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 3
- 239000003377 acid catalyst Substances 0.000 description 3
- 239000012295 chemical reaction liquid Substances 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 239000005416 organic matter Substances 0.000 description 3
- 230000009257 reactivity Effects 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 239000002351 wastewater Substances 0.000 description 3
- 230000002378 acidificating effect Effects 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 239000012298 atmosphere Substances 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 238000005352 clarification Methods 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000012856 packing Methods 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- CIWBSHSKHKDKBQ-JLAZNSOCSA-N Ascorbic acid Chemical compound OC[C@H](O)[C@H]1OC(=O)C(O)=C1O CIWBSHSKHKDKBQ-JLAZNSOCSA-N 0.000 description 1
- LSNNMFCWUKXFEE-UHFFFAOYSA-M Bisulfite Chemical compound OS([O-])=O LSNNMFCWUKXFEE-UHFFFAOYSA-M 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 1
- 230000001174 ascending effect Effects 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000012752 auxiliary agent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000012459 cleaning agent Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000000976 ink Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- GBMDVOWEEQVZKZ-UHFFFAOYSA-N methanol;hydrate Chemical compound O.OC GBMDVOWEEQVZKZ-UHFFFAOYSA-N 0.000 description 1
- 125000005699 methyleneoxy group Chemical group [H]C([H])([*:1])O[*:2] 0.000 description 1
- GRVDJDISBSALJP-UHFFFAOYSA-N methyloxidanyl Chemical compound [O]C GRVDJDISBSALJP-UHFFFAOYSA-N 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229920006324 polyoxymethylene Polymers 0.000 description 1
- -1 polyoxymethylene dimethyl ethers Polymers 0.000 description 1
- 238000007639 printing Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000000859 sublimation Methods 0.000 description 1
- 230000008022 sublimation Effects 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000005829 trimerization reaction Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
Classifications
-
- 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
- B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
- B01J8/08—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with moving particles
- B01J8/10—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with moving particles moved by stirrers or by rotary drums or rotary receptacles or endless belts
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/009—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping in combination with chemical reactions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/34—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping with one or more auxiliary substances
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/48—Preparation of compounds having groups
- C07C41/50—Preparation of compounds having groups by reactions producing groups
- C07C41/56—Preparation of compounds having groups by reactions producing groups by condensation of aldehydes, paraformaldehyde, or ketones
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/48—Preparation of compounds having groups
- C07C41/58—Separation; Purification; Stabilisation; Use of additives
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
A method and a device for preparing polymethoxy dimethyl ether by paraformaldehyde are characterized in that: mixing paraformaldehyde with methanol, heating for reaction to generate hemiacetal, mixing the hemiacetal with recovered material, and catalytically rectifying with methylal under the catalysis of strong acid cation exchange resin to obtain polymethoxy dimethyl ether synthetic liquid, separating and purifying to obtain polymethoxy dimethyl ether, recovering formaldehyde, methylal, macromolecule, etc., and reusing the recovered formaldehyde, methylal, macromolecule, etc., to continue the reaction, wherein the synthesizing device mainly comprises: the catalyst comprises a solution polymerization kettle 1, a catalytic rectifying tower 2, a methanol condenser 3, a stirrer 4, a mixer 5, an azeotrope condenser 6, a solution polymerization kettle heating jacket 7, a catalytic rectifying tower heater 8, a methanol metering tank 20, a solution polymerization kettle thermo-well tube 21, a catalytic rectifying tower stripping section 22, a catalytic rectifying tower catalytic reaction section 23 and a catalytic rectifying tower rectifying section 24.
Description
Technical Field
The invention belongs to the technical field of energy and chemical industry, and particularly relates to a method and a device for preparing polymethoxy dimethyl ether from paraformaldehyde.
Background
Polymethoxy dimethyl ether, also known as paraformaldehyde dimethyl ether, english name: polyoxymethylene dimethyl ethers, PODE or DMMn for short, is a low molecular weight acetal polymer with dimethoxy methane as a matrix and methyleneoxy as a main chain, and has the general formula shown as follows: CH3O (CH 2O) nCH3. Wherein, the polymethoxy dimethyl ether with the polymerization degree of 3-8 is abbreviated as DMM3-8, which is used for cleaning the blending components of diesel oil, the physical properties of the blending components are similar to those of the diesel oil, and the blending components are used in the diesel oil without modifying the oil supply system of the vehicle engine. The cetane number of the diesel oil is up to 76, the oxygen content is 47% -50%, the diesel oil is free of sulfur and aromatic hydrocarbon, 10% -20% of the diesel oil is blended in the diesel oil, the cold filter plugging point of the diesel oil can be obviously reduced, the combustion quality of the diesel oil in an engine can be improved, and the thermal efficiency is improved. Simultaneously, DMM2, DMM3, DMM4, DMM2-3, DMM3-4 and DMM4-6 are also solvents with extremely strong dissolving capacity, and are applied to paint, coating, printing ink, adhesive, cleaning agent, electrolyte solvent and the like.
Polymethoxy dimethyl ether is generally prepared by reacting methanol or methylal with trioxymethylene or paraformaldehyde in the presence of an acidic catalyst, and the basic equation of the reaction is as follows:
the acid catalyst is used for catalyzing and synthesizing the polymethoxy dimethyl ether, the content of a finished product component (DMM 3-8) in the synthetic liquid is lower and is generally lower than 40%, but the existence of a small amount of water promotes the balance to reversely move and has larger influence, so that a large amount of methanol, formaldehyde, paraformaldehyde, hemiacetal and the like are remained in the reaction liquid, the content of an effective component is lower, and the purification and low-cost preparation of the polymethoxy dimethyl ether are difficult; although the system water can be continuously removed in the synthesis process by utilizing the reactive distillation method to synthesize the polymethoxy dimethyl ether, so that the reaction yield is improved, the energy consumption is larger in the removal process of the excessive water, so that the cost is higher; it is therefore conceivable to use anhydrous or low-moisture formaldehyde, which is thought to be the synthesis of polymethoxy dimethyl ether by means of trioxymethylene, paraformaldehyde, synthetic anhydrous or low-moisture gaseous formaldehyde; among them, paraformaldehyde is easy to prepare, low in moisture content and low in cost, and is a good choice.
The catalyst for synthesizing the polymethoxy dimethyl ether generally comprises a liquid acid catalyst and a solid acid catalyst, wherein the liquid acid catalyst has high activity and good catalytic effect, but after the reaction is finished, alkali is added to neutralize the catalyst, so that waste water and organic matters are generated, water is introduced into the synthetic liquid, and the recycling of reclaimed materials is influenced; the sulfonic acid cation exchange resin is used as a solid acid catalyst for catalyzing and synthesizing the polymethoxy dimethyl ether, has good catalytic effect, is easy to separate after the reaction, and is the best choice of scientific researchers for numerous researches on the synthesis of the polymethoxy dimethyl ether; however, paraformaldehyde is not easy to dissolve or melt at a lower temperature, the solid acid catalyst is difficult to have an ideal catalytic effect, and the sulfonic cation exchange resin is easy to remove sulfonic groups at a higher temperature, so that the catalyst is easy to lose effectiveness, and after acidic substances are remained in the polymethoxy dimethyl ether synthetic liquid, the subsequent separation work is difficult.
So domestic and foreign use paraformaldehyde and methylal as raw materials and solid acid as catalyst to synthesize polymethoxy dimethyl ether, which has not been successful in industrialization.
Disclosure of Invention
(1) The invention aims to:
the invention aims to solve the problems that the conventional method for synthesizing the polymethoxy dimethyl ether by using the polymethoxy dimethyl ether as a raw material and using a solid acid catalyst is difficult to dissolve, the catalyst is difficult to have a good catalytic effect, and the like. The method has the advantages of low cost and easy acquisition of raw materials, convenience in realizing continuity and automation, low catalytic reaction temperature, no damage to a solid acid catalyst, active control of reaction balance during dehydration and condensation, high total yield, normal pressure operation, low cost, less waste water, low pollution, safety and environmental protection, and suitability for industrial production.
(2) The technical scheme is as follows:
the invention relates to a method for preparing polymethoxy dimethyl ether by paraformaldehyde and methanol, which comprises mixing paraformaldehyde and methanol, heating to depolymerize the paraformaldehyde, re-polymerizing and arranging the paraformaldehyde on a molecular chain with single methanol as a single terminal group to form hemiacetal with lower melting point and higher reactivity, mixing the hemiacetal with higher reactivity with reclaimed materials, feeding the hemiacetal into a catalytic rectifying tower from the upper part of a filling catalyst filler section, flowing downwards in a dispersed manner under a certain condition, passing through a catalyst filler layer, vaporizing with methylal entering from the lower part of the filling catalyst filler section, countercurrent contacting, carrying out water and methanol generated by reaction along with methylal, generating polymethoxy dimethyl ether, continuing to move downwards, obtaining polymethoxy dimethyl ether synthetic liquid after passing through a stripping section filled with aluminosilicate molecular sieve filler, further separating and recycling low boiling substances and macromolecules to obtain polymethoxy dimethyl ether with different grades, wherein the basic reaction equation is as follows:
the synthesizing device mainly comprises: the catalyst comprises a solution polymerization kettle 1, a catalytic rectification tower 2, a methanol condenser 3, a stirrer 4, a mixer 5, an azeotrope condenser 6, a solution polymerization kettle heating jacket 7, a catalytic rectification tower heater 8, a methanol discharging pipe 9, a hemiacetal discharging pipe 10, a solid paraformaldehyde charging port 11, a solution polymerization kettle pressure balance port 12, a methanol feeding pipe 13, a recovery feeding pipe 14, a mixture feeding pipe 15, a fine methylal feeding pipe 16, an azeotrope return pipe 17, a DMMn synthetic liquid discharging pipe 18, an azeotrope discharging pipe 19, a methanol metering tank 20, a solution polymerization kettle thermometer sleeve 21, a catalytic rectification tower stripping section 22, a catalytic rectification tower catalytic reaction section 23 and a catalytic rectification tower rectifying section 24.
(3) The technical effects are as follows: the method and the device for preparing the polymethoxy dimethyl ether from the paraformaldehyde have the advantages of low price, normal-pressure feeding of solid paraformaldehyde, simple process, convenience for realizing continuity and automation, control of reaction balance to gradually move in the forward direction during catalytic reaction, low energy consumption, high atomic utilization rate, high yield, low cost, low wastewater pollution, safety and environmental protection, and suitability for industrial production, and raw materials of the method and the device are paraformaldehyde, methanol and methylal.
The specific aspects are as follows:
1. the invention adopts paraformaldehyde as the raw material of formaldehyde source, so that the production is simpler and the product cost is lower.
2. The invention adopts methanol as an auxiliary agent to prepare the low-moisture-content oligomeric hemiacetal, has high reactivity, stable and reliable melting point, good fluidity, no sublimation, high efficiency, easy operation and no pollution to subsequent materials.
3. The invention solves the problems of insoluble and infusible solid property of paraformaldehyde, such as low activity and difficult transportation.
4. In the reaction process, the water generated by the reaction is brought out by azeotropy, so that the reaction balance is promoted to move forward, all hydroxyl groups are almost completely sealed, the etherification rate is high, the effective product yield is high, and the synthesis efficiency is high.
5. The reaction process of the invention controls the molecular weight distribution of the synthetic liquid by proper adjustment, thereby greatly improving the synthetic efficiency.
6. The continuous device of the invention can make the productivity of a single device bigger.
7. The invention uses solid acid catalyst, which has good catalytic effect, safety and environmental protection.
8. The invention uses molecular sieve filler to fill the extracting section, plays a role in stabilizing the synthetic liquid, and improves the separation efficiency and the separation yield.
4. Description of the drawings:
fig. 1 is a diagram of an apparatus of the present invention, comprising: the catalyst comprises a solution polymerization kettle 1, a catalytic rectification tower 2, a methanol condenser 3, a stirrer 4, a mixer 5, an azeotrope condenser 6, a solution polymerization kettle heating jacket 7, a catalytic rectification tower heater 8, a methanol discharging pipe 9, a hemiacetal discharging pipe 10, a solid paraformaldehyde charging port 11, a solution polymerization kettle pressure balance port 12, a methanol feeding pipe 13, a recovery feeding pipe 14, a mixture feeding pipe 15, a fine methylal feeding pipe 16, an azeotrope return pipe 17, a DMMn synthetic liquid discharging pipe 18, an azeotrope discharging pipe 19, a methanol metering tank 20, a solution polymerization kettle thermometer sleeve 21, a catalytic rectification tower stripping section 22, a catalytic rectification tower catalytic reaction section 23 and a catalytic rectification tower rectifying section 24.
5. The specific embodiments of the present invention are as follows:
the invention will now be described in further detail with reference to the drawings and by means of specific examples, which are given by way of illustration only and are not intended to limit the scope of the invention.
As shown in fig. 1, the device of the method for preparing polymethoxy dimethyl ether by paraformaldehyde mainly comprises: the catalyst comprises a solution polymerization kettle 1, a catalytic rectification tower 2, a methanol condenser 3, a stirrer 4, a mixer 5, an azeotrope condenser 6, a solution polymerization kettle heating jacket 7, a catalytic rectification tower heater 8, a methanol discharging pipe 9, a hemiacetal discharging pipe 10, a solid paraformaldehyde charging port 11, a solution polymerization kettle pressure balance port 12, a methanol feeding pipe 13, a recovery feeding pipe 14, a mixture feeding pipe 15, a fine methylal feeding pipe 16, an azeotrope return pipe 17, a DMMn synthetic liquid discharging pipe 18, an azeotrope discharging pipe 19, a methanol metering tank 20, a solution polymerization kettle thermometer sleeve 21, a catalytic rectification tower stripping section 22, a catalytic rectification tower catalytic reaction section 23 and a catalytic rectification tower rectifying section 24.
The mass ratio of the paraformaldehyde to the methanol is as follows: methanol=1-10:1, then the solid paraformaldehyde is added into a solution polymerization kettle 1 through a solid paraformaldehyde feeding hole 11, then a heating medium is introduced into a solution polymerization kettle heating sleeve 7, the temperature is raised to 65-165 ℃ and the solution polymerization kettle is subjected to reflux reaction through a methanol condenser 3, constant pressure is kept through a solution polymerization kettle pressure balance hole 12 and is communicated with the atmosphere or certain pressure is kept according to specific requirements, after the solid paraformaldehyde is completely dissolved, the hemiacetal is continuously extracted from a hemiacetal discharging pipe 10 at the bottom of the reaction kettle, mixed with a recycle material 14 in a mixer 5, enters a distributor of a catalytic rectifying tower from the upper part of a catalytic reaction section 23 filled with catalyst filler through a mixture feeding pipe 15, flows downwards in a dispersed mode, flows back through a tower bottom heating 8 and a tower top reflux 17, the temperature of the catalytic rectifying tower bottom 8 is controlled to be 65-135 ℃, the temperature of the catalytic reaction section 23 is controlled to be 45-95 ℃, and the temperature of the tower top is controlled to be 35-75 ℃, the mixture is in countercurrent contact after being gasified with refined methylal continuously entering from the lower part of a section 23 filled with the catalyst filler through a catalyst filler layer 23, water and methanol carried by the mixture and water and methanol generated by reaction are carried out azeotropically along with upward gaseous methylal, after being condensed by an azeotrope condenser 6, a part of the mixture flows back to the top of the tower through an azeotrope return pipe 17, a part of the mixture is extracted through an azeotrope discharge pipe 19, the polymethoxy dimethyl ether is continuously generated by catalysis, hydroxyl groups in the mixture are almost totally capped and etherified, after passing through a stripping section 22 filled with aluminosilicate molecular sieve filler, the polymethoxy dimethyl ether synthetic liquid is intensively collected at the bottom 8 of the tower and is continuously extracted from a DMMn synthetic liquid discharge pipe 18 at the bottom of a reaction rectifying tower, the polymethoxy dimethyl ether synthetic liquid is separated and purified to prepare finished polymethoxy dimethyl ether (DMM 2, DMM3, DMM4, DMM3-6, DMM3-8, and the like), and the recovered formaldehyde, methylal, macromolecules, and the like are returned to the reuse to continue the reaction.
Example 1:
according to the specific preparation method, 75kg of paraformaldehyde (content 96%) and 25kg of methanol are put into a 150L solution polymerization kettle through a solid paraformaldehyde feed inlet 11, then the solution polymerization kettle is covered with the feed inlet, heat conduction oil is introduced through a heating sleeve of the solution polymerization kettle, the temperature is gradually increased to 115 ℃, the solution polymerization kettle is subjected to reflux reaction for 3 hours through a methanol condenser, and is communicated with the atmosphere or a constant pressure system through a pressure balance port of the solution polymerization kettle to keep constant pressure, after the solid paraformaldehyde is completely dissolved, hemiacetal is continuously extracted from a hemiacetal discharge pipe at the bottom of the reaction kettle at a speed of 2 kg/hour, mixed with recovered low-boiling substances and macromolecular substances in a mixer, enters a distributor of a catalytic rectifying tower from the upper part of a filling section of the catalyst, flows downwards, continuously enters the refined methylal from the lower part of the filling section of the catalyst at a speed of 17000mL/h, after heated and vaporized, the mixture moves upwards, the bottom of the catalytic rectifying tower is controlled at 90 ℃ through heating, the temperature of the catalytic section is controlled at 62 ℃, the temperature of the top of the tower is controlled at 41 ℃ through reflux of the top of the tower, the mixture passes through a catalyst packing layer and contacts with rising gaseous refined methylal in countercurrent, water carried by the semiacetal and water generated by reaction are carried out azeotropically along with the gaseous methylal upwards to generate the polymethoxy dimethyl ether, hydroxyl groups in the mixture are almost totally blocked and etherified, the mixture is concentrated at the bottom of the tower after passing through a stripping section filled with aluminosilicate molecular sieve packing to obtain polymethoxy dimethyl ether synthetic liquid, the polymethoxy dimethyl ether synthetic liquid is continuously extracted from the bottom of the reactive rectifying tower, low-boiling substances and macromolecules (applied to a mixer) are recovered through further separation, and then the polymethoxy dimethyl ether finished product is obtained, after 10 hours of continuous feeding, 21.5kg of hemiacetal is consumed, 31.44kg of DMM3-8 mixture is obtained after rectification and separation, and the total yield of organic matters is 97.0 percent after total (deducting the reclaimed materials). The weight yield to formaldehyde (reduced purity) was 203%.
Example 2: (comparative example: without recycle)
The hemiacetal is prepared by the preparation method of the hemiacetal, the hemiacetal is continuously extracted from a hemiacetal discharging pipe at the bottom of a reaction kettle at the speed of 2 kg/hour, is mixed with methylal in a mixer, enters a distributor of a catalytic rectifying tower from the upper part of a filling catalyst filler section, flows downwards, continuously enters refined methylal from the lower part of the filling catalyst filler section at the speed of 17000 mL/hour, moves upwards after being heated and gasified, the temperature of the bottom of the catalytic rectifying tower is controlled at 90 ℃ by heating control, the temperature of the top of the catalytic section is controlled at 62 ℃ by tower top reflux control, the mixture passes through a catalyst filler layer and is in countercurrent contact with ascending gaseous refined methylal, the water carried by the hemiacetal and the water generated by the reaction are carried out azeotropically along with the gaseous methylal upwards, the polymethoxy dimethyl ether is generated and continuously goes downwards, the hydroxyl groups in the mixed material are almost totally blocked and etherified, polymethoxy dimethyl ether synthetic liquid is collected in a concentrated way at the bottom of a stripping section filled with aluminosilicate molecular sieve filler, the polymethoxy dimethyl ether synthetic liquid is continuously extracted from the bottom of a reaction rectifying tower, low-boiling substances and macromolecules are recovered through further separation (applied to a mixer) to obtain a polymethoxy dimethyl ether finished product, 20.3kg of the hemiacetal is consumed after continuous feeding for 10 hours, 24.6kg of a DMM3-8 mixture is obtained after rectification separation, and the total organic matter yield is 97.6% after buckling recovery. The weight yield to formaldehyde (reduced purity) was 168.3%.
Example 3: comparative example batch Synthesis
The hemiacetal is prepared according to the preparation method of the hemiacetal, 1kg of the hemiacetal is taken and put into a 5L pressure reactor, 2kg of refined methylal and 50g of large Kong Huangsuan resin dry product are added, after sealing, the temperature is raised to 60 ℃ and stirring is carried out for 2 hours, 2880g of synthesized liquid is discharged, and after analysis, the synthesized liquid is formed into groups: (%)
| Methanol | Water and its preparation method | DMM1 | DMM2 | DMM3 | DMM4 | DMM5 | DMM6 | DMM7 | DMM8 | DMM9 | Formaldehyde |
| 7.14 | 1.49 | 38.61 | 17.94 | 12.95 | 6.06 | 2.27 | 0.94 | 0.33 | 0.10 | 0.06 | 12.1 |
After low-boiling substances and formaldehyde are distilled off at the normal pressure and the temperature of 140 ℃, 453g of DMM3-8 is collected, and the total organic matter yield is 89.6% (more low-boiling substances are lost) after the recovery material is deducted. The weight yield to formaldehyde (reduced purity) was 62.9%.
Example 4: (comparative example: dissolution without methanol)
250g (96%) of paraformaldehyde is taken and put into a 1L pressure reactor, 500g of refined methylal and 20g of large Kong Huangsuan resin dry product are added, after sealing, the temperature is raised to 60 ℃ and stirring reaction is carried out for 2 hours, and then the feed liquid is turbid, and the paraformaldehyde is granular and has almost no reaction phenomenon.
Example 5: (comparative example: dissolution without methanol)
250g (96%) of paraformaldehyde is taken and put into a 1L pressure reactor, 500g of refined methylal and 20g of large Kong Huangsuan resin dry product are added, after sealing, the temperature is raised to 120 ℃ and stirring reaction is carried out for 2 hours, 719g (clarification) of reaction liquid is discharged, and the mixture is formed by analysis: (%)
| Methanol | Trimerization | Methyl formate | Water and its preparation method | DMM1 | DMM2 | DMM3 | DMM4 | DMM5 | DMM6 | DMM7 | DMM8 | DMM9 | DMM10 | Formaldehyde |
| 2.3 | 2.8 | 3.06 | 0.33 | 32.8 | 18.14 | 13.4 | 8.59 | 5.14 | 2.88 | 1.57 | 0.85 | 0.45 | 0.23 | 5.82 |
After low-boiling substances and formaldehyde are distilled off at the normal pressure and the temperature of 140 ℃, 46.6g of DMM3-8 is collected, and the total organic matter yield is 58.6% (the loss of the low-boiling substances is more) after the recovery materials are deducted. The weight yield to formaldehyde (reduced purity) was 19.4% (severe decomposition of the product components).
Example 6: ( Comparative example: without dissolving in methanol and using liquid sulfuric acid as catalyst )
250g (96%) of paraformaldehyde is taken and put into a 1L pressure reactor, 500g of refined methylal and 1.3g of concentrated sulfuric acid are added, after sealing, the temperature is raised to 60 ℃ and stirring reaction is carried out for 2 hours, 745g (clarification) of reaction liquid is discharged, and the mixture is formed by analysis: (%)
| Methanol | TOX | Methyl formate | Water and its preparation method | DMM1 | DMM2 | DMM3 | DMM4 | DMM5 | DMM6 | DMM7 | DMM8 | DMM9 | DMM10 | Formaldehyde |
| 2.47 | 1.0 | 0.03 | 0.27 | 32.5 | 18.8 | 15.42 | 10.9 | 6.6 | 3.37 | 1.53 | 0.64 | 0.19 | 0.01 | 5.29 |
26g of 5% aqueous alkali solution was added for neutralization, and the aqueous layer was separated, and after distillation of low boiling substances and formaldehyde at 140℃and atmospheric pressure, 195g of DMM3-8 was collected, and the total yield of organic matters (more loss of low boiling substances) was 94.2% by total (deducting the recovered materials). The weight yield to formaldehyde (reduced purity) was 81.3%.
The invention solves the problems that the solid state of the paraformaldehyde is unfavorable for continuous transportation, the activity of the paraformaldehyde is low, the melting point is high, the reaction temperature needs to reach more than 110 ℃ when solid acid is used as a catalyst, the solid acid catalyst is easy to deacidify and deactivate, the stability of the synthetic liquid separation is poor, the byproducts are more, the yield is low, the energy consumption is high, the separation is difficult, and the like when the paraformaldehyde is used as the raw material for producing the polymethoxy dimethyl ether at present. According to the invention, paraformaldehyde and methanol are firstly dissolved into hemiacetal, then a catalytic reaction rectifying tower is utilized, and the polymethoxy dimethyl ether is continuously catalyzed and synthesized under the catalysis of a solid acid catalyst, so that the conventional reaction balance etherification is thoroughly broken, the process is simple, the synthetic conversion rate is higher, the separation is easy after the process is reformed by a molecular sieve filling section, the byproducts are fewer, and the content proportion of excellent components DMM3-4 in the product DMM3-8 is higher. The invention has low investment cost, low production and driving risk and high operation profit.
Finally, the following is to be described: the foregoing description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but although the present invention has been described in detail with reference to the foregoing examples, it will be apparent to those skilled in the art that modifications may be made to the technical solutions described in the foregoing embodiments, or equivalents may be substituted for some of the technical features thereof. Such as: dissolving gaseous formaldehyde into methanol, mixing a certain amount of trioxymethylene into the prepared hemiacetal, and introducing the catalytic rectifying tower into an auxiliary azeotropic water carrying agent along with the methylal, wherein any modification, equivalent replacement, improvement and the like which are made are included in the scope of the invention.
Claims (10)
1. The method and the device for preparing the polymethoxy dimethyl ether by the paraformaldehyde are characterized by comprising the following steps: after mixing paraformaldehyde and methanol, heating for reaction to generate hemiacetal, then removing methylal from the hemiacetal or the mixture of the hemiacetal and reclaimed materials, and carrying out etherification end-capping reaction on the hemiacetal or the mixture of the hemiacetal and reclaimed materials in a reactor filled with a solid acid catalyst to obtain polymethoxy dimethyl ether synthetic liquid, wherein the polymethoxy dimethyl ether synthetic liquid is separated and purified to prepare finished polymethoxy dimethyl ether, the finished polymethoxy dimethyl ether comprises DMM2, DMM3, DMM4, DMM3-6, DMM3-8 and the like, and formaldehyde, methylal, macromolecules and the like recovered after separation and purification of the polymethoxy dimethyl ether synthetic liquid are returned to be used for continuous reaction, and the synthesis device mainly comprises: the catalyst comprises a solution polymerization kettle 1, a catalytic rectification tower 2, a methanol condenser 3, a stirrer 4, a mixer 5, an azeotrope condenser 6, a solution polymerization kettle heating jacket 7, a catalytic rectification tower heater 8, a methanol discharging pipe 9, a hemiacetal discharging pipe 10, a solid paraformaldehyde charging port 11, a solution polymerization kettle pressure balance port 12, a methanol feeding pipe 13, a recovery feeding pipe 14, a mixture feeding pipe 15, a fine methylal feeding pipe 16, an azeotrope return pipe 17, a DMMn synthetic liquid discharging pipe 18, an azeotrope discharging pipe 19, a methanol metering tank 20, a solution polymerization kettle thermometer sleeve 21, a catalytic rectification tower stripping section 22, a catalytic rectification tower catalytic reaction section 23 and a catalytic rectification tower rectifying section 24.
2. The method according to claim 1, wherein the raw material paraformaldehyde is solid paraformaldehyde particles or powder with a content of 93% or more in a commercial form.
3. The method according to claim 1, wherein the raw material methanol is anhydrous methanol having a content of 98% or more.
4. The method according to claim 1, wherein the raw methylal is anhydrous fine methylal or crude methylal.
5. The method according to claim 1, wherein the mass ratio of paraformaldehyde to methanol is paraformaldehyde: methanol=1 to 10:1.
6. The method of claim 1, wherein the solid acid catalyst is a strong acid cation exchange resin and modifications thereof.
7. The method according to claim 1, wherein the reaction temperature of paraformaldehyde and methanol is 65-165 ℃.
8. The method according to claim 1, wherein the reactor comprises a pressure reactor or a reactive distillation column.
9. The method according to claim 1 or 8, wherein the reaction temperature of the pressure reactor is 40-80 ℃.
10. The method according to claim 1 and 8, wherein the temperature of the top of the catalytic rectifying tower is controlled to be 35-75 ℃, the temperature of the catalytic section is controlled to be 45-95 ℃, and the temperature of the bottom of the catalytic rectifying tower is controlled to be 65-135 ℃.
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