CN109824466A - A method of preparing 2- methyl-1,3-pentylene - Google Patents
A method of preparing 2- methyl-1,3-pentylene Download PDFInfo
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- CN109824466A CN109824466A CN201910201904.3A CN201910201904A CN109824466A CN 109824466 A CN109824466 A CN 109824466A CN 201910201904 A CN201910201904 A CN 201910201904A CN 109824466 A CN109824466 A CN 109824466A
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Abstract
A kind of to prepare 2- methyl-1, the method for 3- pentadiene is related to 2- methyl-1,3- pentadiene.2- methyl -2,4 pentanediol is sloughed into a molecular water, obtains 4- methyl -4- amylene -2- alcohol；4- methyl -4- amylene -2- alcohol is sloughed into a molecular water, obtains 2- methyl-1,3- pentadiene.2- methyl-1, the yield of 3- pentadiene, 2- methyl-1,3- pentadiene and 4- methyl-1 are improved, the ratio of 3 pentadienes can be improved to 9 ︰ 1,2- methyl-1, and the yield of 3- pentadiene is greater than 80%.Using weakly acidic catalyst, the loss to equipment is reduced.Mild catalyst is selected, the loss to equipment is reduced, improves the environment friendly of reaction.Using the method for substep dehydration, reaction is set to greatly reduce 4- methyl-1, the generation of 3 pentadienes improves 2- methyl-1, the yield of 3 pentadienes.
Description
Technical field
The present invention relates to 2- methyl-1,3- pentadiene prepares 2- methyl-1, the side of 3- pentadiene more particularly, to a kind of
Method.
Background technique
2- methyl-1,3- pentadiene are the important intermediates of synthetic perfume, it can be carried out with other unsaturated alkene
Diels-Alder reaction, synthesizing cyclohexane 1 vinyl derivative perfume molecules, such as ligustral.Ligustral has strong green grass and hay-scented
Fragrance can be used in daily chemical essence formula, be particularly appropriate for soap, synthetic detergent, cosmetic essence formula.It can increase essence
Freshness and extension.Whole world demand belongs to important perfume material at 2000 tons/year or so at present.Therefore ligustral is prepared
Precursor 2- methyl-1,3-pentylene is particularly important.
The method for preparing 2- methyl-1,3-pentylene at present is mainly -2,4 pentanediol of 2- methyl as made of condensation of acetone
It is dehydrated and obtains, British patent GB572602 discloses 2- methyl -2,4 pentanediol dehydration preparation 2- methyl-under iodine or hydrochloric acid effect
1,3-pentadiene and 4- methyl-1,3 pentadiene mixtures, but the catalyst of strong acid has strong corrosion to consersion unit
Property.It is catalyst that United States Patent (USP) US20060058561, which then utilizes mineral acid salt, and the dehydration for carrying out 2- methyl -2,4 pentanediol is anti-
It answers.Obtain 2- methyl-1,3-pentylene and 4- methyl-1, the mixture of 3 pentadienes.Addition polyethylene glycols are also needed to help in reaction
Agent, to take away reaction heat.Since reaction temperature is higher, industrial application is more difficult.Former Soviet Union patent SU1759825 is in ethylene glycol
Under the conditions of equal solvent, dehydration obtains 2- methyl-1,3- pentadiene and 4- methyl-1, the isomers of 3 pentadienes under inorganic acid catalysis
Mixture, the ratio of two kinds of isomers is between 3 ︰, 1 to 4 ︰ 1.
From the foregoing, it will be observed that 2- methyl-1,3- pentadiene generally passes through 2- methyl -2,4 penta as the intermediate for preparing ligustral
The problems such as diol dehydratase obtains, and it is strong that previous report has a reaction acidity of catalyst more, corrosivity, reaction temperature is high.And
The dehydration of 2- methyl -2,4 pentanediol outside 3- pentadiene, also inevitably generates corresponding isomers in addition to obtaining 2- methyl-1
4- methyl-1,3 pentadienes, the ratio of two kinds of alkene is between 3 ︰, 1 to 4 ︰ 1.Due to 4- methyl-1,3 pentadienes can not be with other not
The alkene of saturation carries out Diels-Alder reaction, can only often be handled as useless by-product, limit 2- methyl-
The yield of 1,3- pentadiene.
Summary of the invention
It is an object of the invention to for existing -2,4 pentanediol of 2- methyl dehydration preparation 2- methyl-1,3-pentylene method
Deficiency, provide that a kind of two steps by using weakly acidic catalyst are dehydrated a kind of prepares 2- methyl-1,3- penta 2
The method of alkene.
The present invention the following steps are included:
1) 2- methyl -2,4 pentanediol is sloughed into a molecular water, obtains 4- methyl -4- amylene -2- alcohol；
2) 4- methyl -4- amylene -2- alcohol is sloughed into a molecular water, obtains 2- methyl-1,3- pentadiene.
In step 1), the specific method that 2- methyl -2,4 pentanediol is sloughed a molecular water can are as follows: connects at top
In the reactor for having thorn shape still and condenser pipe, 2- methyl -2,4 pentanediol steams product 4- methyl -4- while reacting
Amylene -2- alcohol；The temperature of the reaction can be 110~140 DEG C；The catalyst of the reaction can be to be carried on montmorillonite chlorination
The mass ratio of iron, iron chloride and montmorillonite can be (0.05~0.5) ︰ 1.
In step 2), the specific method that 4- methyl -4- amylene -2- alcohol is sloughed a molecular water can are as follows: on a top
Portion is connected in the reactor of thorn shape still and condenser pipe, and 4- methyl -4- amylene -2- alcohol steams product 2- first while reacting
Base -1,3- pentadiene；The temperature of the reaction can be 120~150 DEG C, and the catalyst of the reaction can be oxalic acid, citric acid, sulphur
At least one of potassium hydrogen phthalate, iron chloride etc..
Reaction process of the invention is as follows:
The present invention improves 2- methyl-1, the yield of 3- pentadiene, 2- methyl-1,3- pentadiene and 4- methyl-1, and 3 penta 2
The ratio of alkene can be improved to 9 ︰ 1,2- methyl-1, and the yield of 3- pentadiene is greater than 80%.The present invention uses weakly acidic catalyst,
Reduce the loss to equipment.
The method that the present invention uses the dehydration of two steps, selects mild catalyst, obtains higher 2- methyl-1,3 pentadienes
Yield.Compared with existing other technologies, advantages of the present invention is as follows:
1) mild catalyst is selected, reduces the loss to equipment, improves the environment friendly of reaction.
2) using the method for substep dehydration, reaction is made to greatly reduce 4- methyl-1, the generation of 3 pentadienes improves 2-
Methyl-1, the yield of 3 pentadienes.
Specific embodiment
The present invention is further illustrated for following embodiment.
Embodiment 1
(1) 4- methyl -4- amylene -2- alcohol is prepared
300g2- methyl -2,4 pentanediol is added in the 500ml there-necked flask with stirring magneton, 3g is carried on montmorillonite
Ferric chloride catalyst (0.1 ︰ 1 of iron chloride and the mass ratio of montmorillonite), connect thorn shape still, condenser pipe on there-necked flask and connect
It receives bottle to be reacted in 110~140 DEG C of conditions, produces product 4- methyl -4- amylene -2- alcohol, gas phase in reaction process on one side
Chromatography 4- methyl -4- amylene -2- alcohol content is greater than 90%.4- methyl -4- amylene -2- alcohol is reacted (2).
(2) 2- methyl-1,3 pentadienes are prepared
300g4- methyl -4- amylene -2- alcohol, 6g oxalic acid and chlorination are added in the 500ml there-necked flask with stirring magneton
The mixture (3 ︰ 2 of mass ratio) of iron connects thorn shape still, condenser pipe and receiving bottle on there-necked flask, in 120~150 DEG C of conditions,
It is reacted, produces product 2- methyl-1,3 pentadienes, gas chromatographic analysis 2- methyl-1,3 pentadienes in reaction process on one side
Content is greater than 90% and a small amount of 4- methyl-1,3 amylenes.
Two step 2- methyl-1s, the total recovery 83% of 3 pentadienes.
Embodiment 2
(1) 4- methyl -4- amylene -2- alcohol is prepared
300g2- methyl -2,4 pentanediol is added in the 500ml there-necked flask with stirring magneton, 3g is carried on montmorillonite
Ferric chloride catalyst (0.3 ︰ 1 of iron chloride and the mass ratio of montmorillonite), connect thorn shape still, condenser pipe on there-necked flask and connect
It receives bottle to be reacted in 110~130 DEG C of conditions, produces product 4- methyl -4- amylene -2- alcohol, gas phase in reaction process on one side
Chromatography 4- methyl -4- amylene -2- alcohol content is greater than 90%.4- methyl -4- amylene -2- alcohol is reacted (2).
(2) 2- methyl-1,3 pentadienes are prepared
300g 4- methyl -4- amylene -2- alcohol, 6g oxalic acid and lemon are added in the 500ml there-necked flask with stirring magneton
The mixture (1 ︰ 1 of mass ratio) of acid connects thorn shape still, condenser pipe and receiving bottle on there-necked flask, in 120~150 DEG C of conditions,
It is reacted, produces product 2- methyl-1,3 pentadienes, gas chromatographic analysis 2- methyl-1,3 pentadienes in reaction process on one side
Content is greater than 90%, there was only a small amount of 4- methyl-1,3 amylenes in the product of extraction.
2- methyl-1, the yield 82% of 3 pentadienes.
Embodiment 3
(1) 4- methyl -4- amylene -2- alcohol is prepared
300g 2- methyl -2,4 pentanediol is added in the 500ml there-necked flask with stirring magneton, 3g is carried on montmorillonite
Ferric chloride catalyst (0.5 ︰ 1 of iron chloride and the mass ratio of montmorillonite), connect thorn shape still, condenser pipe on there-necked flask and connect
It receives bottle to be reacted in 110~130 DEG C of conditions, produces product 4- methyl -4- amylene -2- alcohol, gas phase in reaction process on one side
Chromatography 4- methyl -4- amylene -2- alcohol content is greater than 90%.4- methyl -4- amylene -2- alcohol is reacted (2).
(2) 2- methyl-1,3 pentadienes are prepared
With stirring magneton 500ml there-necked flask in be added 300g4- methyl -4- amylene -2- alcohol, 6g potassium acid sulfate and
The mixture (1 ︰ 2 of mass ratio) of citric acid connects thorn shape still, condenser pipe and receiving bottle on there-necked flask, at 120~150 DEG C
Condition is reacted, and produces product 2- methyl-1 in reaction process on one side, 3 pentadienes, gas chromatographic analysis 2- methyl-1, and 3 penta
Diene content is greater than 92%, there was only a small amount of 4- methyl-1,3 amylenes in the product of extraction.
2- methyl-1, the yield 85% of 3 pentadienes.
Claims (8)
1. a kind of prepare 2- methyl-1, the method for 3- pentadiene, it is characterised in that the following steps are included:
1) 2- methyl -2,4 pentanediol is sloughed into a molecular water, obtains 4- methyl -4- amylene -2- alcohol；
2) 4- methyl -4- amylene -2- alcohol is sloughed into a molecular water, obtains 2- methyl-1,3- pentadiene.
2. a kind of as described in claim 1 prepare 2- methyl-1, the method for 3- pentadiene, it is characterised in that in step 1), institute
It states and -2,4 pentanediol of 2- methyl is sloughed into a molecular water method particularly includes: be connected to the anti-of thorn shape still and condenser pipe at top
It answers in device, 2- methyl -2,4 pentanediol steams product 4- methyl -4- amylene -2- alcohol while reacting.
3. a kind of as claimed in claim 2 prepare 2- methyl-1, the method for 3- pentadiene, it is characterised in that the temperature of the reaction
It is 110~140 DEG C.
4. a kind of as claimed in claim 2 prepare 2- methyl-1, the method for 3- pentadiene, it is characterised in that the catalysis of the reaction
Agent is to be carried on montmorillonite iron chloride, and the mass ratio of iron chloride and montmorillonite is (0.05~0.5) ︰ 1.
5. a kind of as described in claim 1 prepare 2- methyl-1, the method for 3- pentadiene, it is characterised in that in step 2), institute
It states and 4- methyl -4- amylene -2- alcohol is sloughed into a molecular water method particularly includes: be connected to thorn shape still and condenser pipe at a top
Reactor in, 4- methyl -4- amylene -2- alcohol steams product 2- methyl-1,3- pentadiene while reacting.
6. a kind of as claimed in claim 5 prepare 2- methyl-1, the method for 3- pentadiene, it is characterised in that the temperature of the reaction
It is 120~150 DEG C.
7. a kind of as claimed in claim 5 prepare 2- methyl-1, the method for 3- pentadiene, it is characterised in that the catalysis of the reaction
Agent is at least one of oxalic acid, citric acid, potassium acid sulfate, iron chloride.
8. a kind of as described in claim 1 prepare 2- methyl-1, the method for 3- pentadiene, it is characterised in that its reaction process is such as
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111925267A (en) * | 2020-07-30 | 2020-11-13 | 山东新和成药业有限公司 | Preparation method of 2-methyl-1, 3-pentadiene |
| CN114380659A (en) * | 2020-10-22 | 2022-04-22 | 中国科学院大连化学物理研究所 | Method for preparing isoprene from isobutene-methanol |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB572602A (en) * | 1942-07-04 | 1945-10-16 | Shell Dev | Production of methyl pentadienes |
| JPS6157525A (en) * | 1984-08-28 | 1986-03-24 | Kao Corp | Production of methylpentadiene |
| SU1759825A1 (en) * | 1990-07-26 | 1992-09-07 | Всесоюзный научно-исследовательский институт синтетических и натуральных душистых веществ | Method of producing a mixture of 2-methyl- and 4-methylpenta-1,3-dienes |
| US20060058561A1 (en) * | 2004-09-11 | 2006-03-16 | Celanese Chemicals Europe Gmbh | Process for dehydrating 2-methylpentane-2,4-diol |
-
2019
- 2019-03-18 CN CN201910201904.3A patent/CN109824466B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB572602A (en) * | 1942-07-04 | 1945-10-16 | Shell Dev | Production of methyl pentadienes |
| JPS6157525A (en) * | 1984-08-28 | 1986-03-24 | Kao Corp | Production of methylpentadiene |
| SU1759825A1 (en) * | 1990-07-26 | 1992-09-07 | Всесоюзный научно-исследовательский институт синтетических и натуральных душистых веществ | Method of producing a mixture of 2-methyl- and 4-methylpenta-1,3-dienes |
| US20060058561A1 (en) * | 2004-09-11 | 2006-03-16 | Celanese Chemicals Europe Gmbh | Process for dehydrating 2-methylpentane-2,4-diol |
Non-Patent Citations (3)
| Title |
|---|
| IPATIEF, V. N.ET AL.,: "Dehydration of 2-methyl-2,4-pentanediol and 4-methyl-x-penten-2-ol under", 《JACS》 * |
| SATOSHI SATO, ET AL.,: "Dehydration of diols catalyzed by CeO2", 《JOURNAL OF MOLECULAR CATALYSIS A:CHEMICAL》 * |
| TRAYNELIS, VINCENT J. ET AL.,: "Dehydration of alcohols, diols, and related compounds in dimethyl", 《JOURNAL OF ORGANIC CHEMISTRY》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111925267A (en) * | 2020-07-30 | 2020-11-13 | 山东新和成药业有限公司 | Preparation method of 2-methyl-1, 3-pentadiene |
| CN111925267B (en) * | 2020-07-30 | 2023-03-28 | 山东新和成药业有限公司 | Preparation method of 2-methyl-1, 3-pentadiene |
| CN114380659A (en) * | 2020-10-22 | 2022-04-22 | 中国科学院大连化学物理研究所 | Method for preparing isoprene from isobutene-methanol |
| CN114380659B (en) * | 2020-10-22 | 2024-01-23 | 中国科学院大连化学物理研究所 | Method for preparing isoprene from isobutene-methanol |
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