CN108586210A - A kind of preparation method of dimethyl ether - Google Patents
A kind of preparation method of dimethyl ether Download PDFInfo
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- CN108586210A CN108586210A CN201810321792.0A CN201810321792A CN108586210A CN 108586210 A CN108586210 A CN 108586210A CN 201810321792 A CN201810321792 A CN 201810321792A CN 108586210 A CN108586210 A CN 108586210A
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- dimethyl ether
- preparation
- reaction
- iodomethane
- azeotropic
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/01—Preparation of ethers
- C07C41/16—Preparation of ethers by reaction of esters of mineral or organic acids with hydroxy or O-metal groups
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/01—Preparation of ethers
- C07C41/34—Separation; Purification; Stabilisation; Use of additives
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/01—Preparation of ethers
- C07C41/34—Separation; Purification; Stabilisation; Use of additives
- C07C41/40—Separation; Purification; Stabilisation; Use of additives by change of physical state, e.g. by crystallisation
- C07C41/42—Separation; Purification; Stabilisation; Use of additives by change of physical state, e.g. by crystallisation by distillation
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- Organic Chemistry (AREA)
- Crystallography & Structural Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The present invention provides a kind of preparation methods of dimethyl ether, it is related to chemical industry synthesis field, for the deficiency of existing dimethyl ether synthesis technology, this programme is using dipropylene glycol and iodomethane as reaction raw materials, under the action of basic catalyst, methylation reaction occurs and generates dimethyl ether, is then again separated target product dimethyl ether from reaction system by separating-purifying.Entire synthesis route is short, and good reaction selectivity is at low cost, and yield is high, and quality is high, and raw material is Ke Xunhuanliyong, is not related to high temperature and pressure, process safety is reliable, and operability is strong, and effect on environment is low.
Description
Technical field
The present invention relates to chemical industry synthesis fields, refer in particular to a kind of preparation method of dimethyl ether.
Background technology
Dimethyl ether is one kind of ternary ether, and structural formula is：CH3O(CH2CH2CH2O)2CH3Molecular formula is
C8H18O3.Dimethyl ether can aoxidize, hydrolysis, can be miscible with water, can be miscible in ethyl alcohol, ether.
Dimethyl ether is a kind of multipurpose environment protection type solvent, there is a faint ethers smell, evaporation rate appropriate,
Chemically excellent stability, extremely excellent solubility property have higher safety to people.The U.S. and European Union are classified as Non
The green solvent of HAP/NAP (Nonhazardous inthe list of air pollution).Usual dipropylene glycol diformazan
Ether can be used for it is aqueous and coating material solidified in, can replace N-Methyl pyrrolidone be used for used in electronic industry cleaning agent, additionally can be used
In synthesis polyurethane etc..
According to the synthesis technology of dimethyl ether in the world at present, mainly use dimethyl sulfate method, i.e., with
Dimethyl suflfate carries out methylation reaction as methylating reagent, with dipropylene glycol, obtains dimethyl ether.The technique
In, severe reaction conditions, product quality is not high, and yield is low, of high cost.
Invention content
The technical problem to be solved by the present invention is to：The synthesis technology of existing dimethyl ether is in the prevalence of reaction
Condition is harsh, and product quality is not high, and yield is low, problem of high cost.To need, one kind is novel, simple, it is industrialized to be suitable for
Dimethyl ether synthesis technology.
In order to solve the above-mentioned technical problem, the invention discloses a kind of preparation methods of dimethyl ether, specifically,
Include the following steps：
S1, it methylates, using dipropylene glycol and iodomethane as raw material, under basic catalyst effect, methylation reaction occurs,
Generate dimethyl ether；
S2, azeotropic dehydration carry out solvent azeotropic dehydration, so to the dimethyl ether system that S1 methylation reactions generate
Cooling salts out afterwards, is filtered to remove salt and obtains filtrate；
S3, product purification, the filtrate progress rectifying separation to gained in S2 azeotropic dehydration steps, normal pressure recycling design, then
The target product dimethyl ether that rectification under vacuum is purified.
Further, in the S1 methylation reactions, the basic catalyst is potassium hydroxide.
Further, in the S1 demethylation steps, material is with the molar ratio of Er Bing bis- Chun ︰ Qing Yangization Jia ︰ iodomethane
The ratio of 1.0 ︰, 2.1~2.2 ︰ 2.0 feeds intake.
Further, in the S1 methylation reactions, reaction temperature is 30~50 DEG C, and reaction pressure is normal pressure.
Further, in the S1 methylation reactions, iodomethane is added by the way of being gradually added dropwise to reaction system
Material.
Further, in the S2 azeotropic dehydrations step, using atent solvent, from S1 methylation reaction systems altogether by water
Boiling comes out, and the temperature of azeotropic dehydration is gradually warming up to 90 DEG C from 60 DEG C under normal pressure.
Further, in the S3 product purifications step, rectification under vacuum temperature is 72~150 DEG C, and the rectification under vacuum
Vacuum degree be -0.09~-0.095MPa, collect 110 DEG C when fraction be dimethyl ether.
Further, the atent solvent in the S2 azeotropic dehydrations step is hexamethylene or butanone.
Further, further include S4 salt recycling steps, the step S2 iodate sylvite being obtained by filtration and step S3 are refined into institute
After the iodate sylvite of precipitation merges, with phosphoric acid in molar ratio 1：1 is reacted, and potassium dihydrogen phosphate and hydrogen iodide, hydrogen iodide are obtained
Absorbed with water is hydroiodic acid.
Further, further include that S5 hydroiodic acids recycle, by the hydroiodic acid of gained in step S4 and 3- methoxypropionic acids
It is reacted according to 1 ︰ 1 of molar ratio, obtains iodomethane.
The preparation method of dimethyl ether disclosed by the invention is mainly that reaction is former with dipropylene glycol and potassium iodide
Material occurs methylation reaction and generates dimethyl ether and other products, then pass through again under the action of basic catalyst
Separating-purifying isolates target product dimethyl ether from reaction system.Entire synthesis route is short, reaction choosing
Selecting property is good, at low cost, and yield is high, and quality is high, and raw material is Ke Xunhuanliyong, is not related to high temperature and pressure, process safety is reliable, operable
Property is strong, and effect on environment is low.
Specific implementation mode
To explain the technical content, the achieved purpose and the effect of the present invention in detail, it is explained in detail below in conjunction with embodiment.
Embodiment 1
It methylates
By 1.05mol dipropylene glycol (DPG), 2.2mol potassium hydroxide solids, 120g butanone is put into reaction kettle as molten
Agent, solvent use hexamethylene or butanone, and it is to play diluting effect that solvent, which is added, in reaction process, the material in extraction filtering salt
Use solvent.Wherein basic catalyst of the potassium hydroxide as the methylation reaction, it is 30 DEG C to keep temperature of reaction kettle, Yu Chang
2mol iodomethane is slowly added dropwise in pressure, drips off within 1~2 hour, and because methylation reaction is exothermic reaction, iodomethane is used and is gradually added dropwise
Mode enter the progress that reaction system is more advantageous to methylation reaction.Then 2~6 hours are kept the temperature again, it is made fully to react, instead
It includes dimethyl ether to answer in product, and specific reaction equation is as follows：
HO(CH2CH2CH2O)2H+2CH3I+2KOH=CH3O(CH2CH2CH2O)2CH3+2KI+2H2O
Extraction
The solidliquid mixture obtained in above-mentioned demethylation step is filtered, solid potassium iodide and dipropylene glycol containing product are obtained
Solid sodium iodide, is used the agitator treatings of butanone 120g × 22 times by the butanone solution of dimethyl ether again, and butanone mixing is obtained by filtration respectively
Liquid merges filtered filtrate three times, includes butanone solvent, water, dimethyl ether and potassium iodide in the filtrate.
Distillation
The filtrate of gained in above-mentioned extraction step is distilled, after steaming whole liquid, and potassium iodide solid is precipitated.
Rectifying
The liquid that step 3 is distilled out carries out atmospheric distillation again, and the fraction being collected at 72 DEG C is butanone, and butanone can also return
It receives and recycles, again separate target product from reaction system as extractant, the fraction being collected at 100 DEG C is
Water, the fraction being collected at 190 DEG C, as final target product dimethyl ether obtain 137g, and yield is up to 85%.
Potassium iodide recycles
It is 284g after obtained potassium iodide solid in extraction step and distilation steps is merged drying, it then will be acquired
Potassium iodide solid and phosphoric acid in molar ratio 1：1 is reacted, and potassium dihydrogen phosphate and hydrogen iodide are obtained, and potassium dihydrogen phosphate filtering is dried
260g being obtained after dry, and the potassium dihydrogen phosphate subsequently can be used as fertilizer application, hydrogen iodide is then absorbed to obtain 40% hydroiodic acid with water,
In case follow-up use, to accomplish that the various products in the step are all recycling.
Hydroiodic acid recycles
By the obtained hydroiodic acid of above-mentioned steps and 3- methoxypropionic acids in molar ratio 1：1 reaction, obtains iodomethane
135.7g and 3- hydracrylic acids so that iodomethane can reuse, and be re-used for methylation reaction, and iodomethane in the program
Recycling rate of waterused is 95.5%.
For whole synthetic schemes, the present invention has synthetic route short, and reaction condition is mild, at low cost, and yield is high,
The characteristics of three-waste free discharge, raw material is recycled recycling, has apparent progress, more suitable for industry compared with the prior art
Metaplasia is produced.
Embodiment 2
Under conditions of other conditions are identical with embodiment 1, butanone is replaced using hexamethylene and makees solvent, final mesh
Product dimethyl ether is marked, obtains 139g, yield is up to 86.2%.
Embodiment 3
Under conditions of other conditions are identical with embodiment 2, Product recycling is carried out using vacuum distillation mode, is collected
Fraction is dimethyl ether at 110 DEG C, and rectifying vacuum degree is -0.09~-0.095MPa.Final target product two
Propylene Glycol Dimethyl Ether, obtains 144g, and yield is up to 89.3%.
For whole synthetic schemes, the present invention has synthetic route short, and reaction condition is mild, at low cost, and yield is high,
The characteristics of three-waste free discharge, raw material is recycled recycling, has apparent progress, more suitable for industry compared with the prior art
Metaplasia is produced.
Example the above is only the implementation of the present invention is not intended to limit the scope of the invention, every to utilize this hair
Equivalent process transformation made by bright description is applied directly or indirectly in other relevant technical fields, and similarly wraps
It includes in the scope of patent protection of the present invention.
Claims (10)
1. a kind of preparation method of dimethyl ether, which is characterized in that include the following steps：
S1, it methylates, using dipropylene glycol and iodomethane as raw material, under basic catalyst effect, methylation reaction occurs, generates
Dimethyl ether；
S2, azeotropic dehydration carry out solvent azeotropic dehydration to the dimethyl ether system that S1 methylation reactions generate, then drop
Temperature salts out, and is filtered to remove salt and obtains filtrate；
S3, product purification carry out rectifying separation, normal pressure recycling design to the filtrate of gained in S2 azeotropic dehydration steps, then depressurize
The target product dimethyl ether that rectifying is purified.
2. the preparation method of dimethyl ether as described in claim 1, which is characterized in that the S1 methylation reactions
In, the basic catalyst is potassium hydroxide.
3. the preparation method of dimethyl ether as claimed in claim 2, which is characterized in that the S1 demethylation steps
In, material is fed intake with the ratio that the molar ratio of Er Bing bis- Chun ︰ Qing Yangization Jia ︰ iodomethane is 1.0 ︰, 2.1~2.2 ︰ 2.0.
4. the preparation method of dimethyl ether as claimed in claim 3, which is characterized in that the S1 methylation reactions
In, reaction temperature is 30~50 DEG C, and reaction pressure is normal pressure.
5. the preparation method of dimethyl ether as claimed in claim 4, which is characterized in that the S1 methylation reactions
In, iodomethane is fed by the way of being gradually added dropwise to reaction system.
6. such as the preparation method of claim 2-5 any one of them dimethyl ethers, which is characterized in that the S2 azeotropic
In dehydration, using atent solvent, by water, azeotropic comes out from S1 methylation reaction systems, the temperature of azeotropic dehydration under normal pressure
It is gradually warming up to 90 DEG C from 60 DEG C.
7. the preparation method of dimethyl ether as claimed in claim 6, which is characterized in that the S3 product purifications step
In, rectification under vacuum temperature is 72~150 DEG C, and the vacuum degree of the rectification under vacuum is -0.09~-0.095MPa, collects 110 DEG C
When fraction be dimethyl ether.
8. the preparation method of dimethyl ether as claimed in claim 7, which is characterized in that the S2 azeotropic dehydrations step
In atent solvent be hexamethylene or butanone.
9. the preparation method of dimethyl ether as claimed in claim 2, which is characterized in that further include S4 salt recycling step
Suddenly, after the refined iodate sylvite be precipitated of the step S2 iodate sylvite being obtained by filtration and step S3 being merged, with phosphoric acid by mole
Than 1：1 is reacted, and obtains potassium dihydrogen phosphate and hydrogen iodide, it is hydroiodic acid that hydrogen iodide water, which absorbs,.
10. the preparation method of dimethyl ether as claimed in claim 9, which is characterized in that further include that S5 hydroiodic acids follow
Ring utilizes, and the hydroiodic acid of gained in step S4 is reacted with 3- methoxypropionic acids according to 1 ︰ 1 of molar ratio, iodomethane is obtained.
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| CN201810321792.0A CN108586210A (en) | 2018-04-11 | 2018-04-11 | A kind of preparation method of dimethyl ether |
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| CN201810321792.0A CN108586210A (en) | 2018-04-11 | 2018-04-11 | A kind of preparation method of dimethyl ether |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3635447A1 (en) * | 1986-10-18 | 1988-04-21 | Hoechst Ag | Process for the preparation of aliphatic compounds containing 2 to 6 alkoxy groups |
| CN102295519A (en) * | 2011-07-26 | 2011-12-28 | 太仓沪试试剂有限公司 | Preparation method for iodomethane |
| JP2015196680A (en) * | 2014-03-31 | 2015-11-09 | 日本乳化剤株式会社 | (poly)alkylene glycol dialkyl ether production method |
| WO2017174953A1 (en) * | 2016-04-07 | 2017-10-12 | Pivert | Alkylation method |
-
2018
- 2018-04-11 CN CN201810321792.0A patent/CN108586210A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3635447A1 (en) * | 1986-10-18 | 1988-04-21 | Hoechst Ag | Process for the preparation of aliphatic compounds containing 2 to 6 alkoxy groups |
| CN102295519A (en) * | 2011-07-26 | 2011-12-28 | 太仓沪试试剂有限公司 | Preparation method for iodomethane |
| JP2015196680A (en) * | 2014-03-31 | 2015-11-09 | 日本乳化剤株式会社 | (poly)alkylene glycol dialkyl ether production method |
| WO2017174953A1 (en) * | 2016-04-07 | 2017-10-12 | Pivert | Alkylation method |
Non-Patent Citations (1)
| Title |
|---|
| 杨振平,等: "制备碘甲烷不同方法比较", 《浙江工业大学学报》 * |
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Application publication date: 20180928 |