Method for synthesizing diene compounds based on aldehyde-ketone condensation reaction

A technology of ketone compounds and aldehyde compounds, applied in the field of diolefin synthesis, which can solve the problems of low yield, easy deactivation of catalysts, high reaction temperature, etc.

Inactive Publication Date: 2019-04-26
CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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Problems solved by technology

[0004] Benefiting from the rapid development of the bioethanol industry in recent years, the production of butadiene from ethanol has attracted much attention. This technology is divided into a two-step method and a one-step method. The reaction temperature is high (>300°C), and the requirements for the catalyst are high. The yield is difficult to exceed 60%. To increase the yield, a certain proportion of acetaldehyde must be mixed in the raw material, and the cost is relatively high.
Subsequently, a two-step synthesis route of butadiene was developed using C4 diol and C4 unsaturated alcohol as raw materials. Although this technology effectively improves the product yield, the two-step reaction still needs to be carried out at high temperature (>300°C). Higher yields may be obtained (Chem.Soc.Rev., 2014, 43, 7917-7953, Chem.Lett.2016, 45, 1036-1047)
In 2017, it was reported that tetrahydrofuran was used as raw material, and butadiene was formed after ring-opening with solid acid as a catalyst at 350°C, and the yield could reach 76%. Similarly, using 2-methyltetrahydrofuran as a raw material, m Pentadiene, but the catalyst is easily deactivated due to the rapid generation of carbon deposits, and the piperylene production rate decreases rapidly from 67.8% to 51.8%, and this data is obtained when the feed rate of the raw material is very small (the space velocity is 0.2s -1 ), increase the airspeed (>10s -1 ), the raw material conversion rate is reduced to <8.9%, so the production capacity of butadiene and piperylene prepared by this method is difficult to improve (ACSSustainable Chem.Eng.2017,5,3732-3736, ACS Catal.2017,7,5248-5256 )

Method used

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  • Method for synthesizing diene compounds based on aldehyde-ketone condensation reaction
  • Method for synthesizing diene compounds based on aldehyde-ketone condensation reaction
  • Method for synthesizing diene compounds based on aldehyde-ketone condensation reaction

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preparation example Construction

[0138] The preparation method of the supported heteropolyacid compound catalyst is as follows: at room temperature to 60°C and under stirring conditions, the carrier is added to the catalyst mother liquor, impregnated in equal volume, stirred for 6 to 24 hours, and then filtered, and the obtained solid catalyst is in the drying in an oven at 80-120° C. for 5-10 hours to obtain a supported catalyst. The catalyst preparation temperature is preferably room temperature-50°C; the stirring time is preferably 5-18 hours, more preferably 10-15 hours; the drying temperature is preferably 100-120°C; the drying time is preferably 7-10 hours. Among them, the carrier is preferably commercial Al 2 o 3 , SiO 2 , Molecular sieve series, no need to deal with. The molecular sieve series can specifically be one or more of ZSM, BEA, SBA, MCM, SAPO, AlPO, 3 / 4 / 5A molecular sieve, β molecular sieve and other series of molecular sieves, more preferably Al 2 o 3 , SiO 2 , ZSM, SBA, MCM, SAPO or ...

Embodiment 1

[0157] 1. Condensation reaction and catalyst

[0158] Acetone and paraformaldehyde weighed a total of 21g according to 7:3 (molar ratio), placed in a 100mL stainless steel reaction kettle with a PTFE liner, and added 0.3g Mg(OH) 2 20g of methanol / water (mass ratio 5:1) solution, sealed and stirred at 50°C for 10h, extracted with 3×10mL dichloromethane after the reaction, combined organic phases with rotary evaporation to obtain the condensation product, and the conversion rate of paraformaldehyde was ~93, the condensation product yield is ~82%;

[0159] The condensation product prepared in Example 1 of the present invention was characterized.

[0160] see figure 2 , figure 2 It is the MS spectrum of the condensation product prepared in Example 1 of the present invention.

[0161] 2. Reduction reaction and catalyst

[0162] Take 4g of the condensation product and place it in an ice bath in a 250mL round bottom flask, add a total of 50mL of tetrahydrofuran / water (volume r...

Embodiment 2

[0173] 1. Condensation reaction and catalyst

[0174] Butanone and formaldehyde 7:1 (molar ratio) weighed a total of 24g, placed in a 100mL stainless steel reactor with tetrafluoro liner, added 0.5g NH 4 -ZSM-5 catalyst and 20g methanol / water (mass ratio 5:1) solution, sealed and stirred at 35°C for 4h, extracted with 3×10mL dichloromethane after the reaction, combined organic phase and rotary evaporation to obtain the condensation product, formaldehyde The conversion rate was ~96%, and the condensation product yield was ~85%;

[0175] NH used 4 -The preparation of the ZSM-5 catalyst is as follows: under stirring conditions, 10g ZSM-5 is added to 100mL of prepared 20% ammonia water, stirred at room temperature for 12h, then filtered, and the resulting solid is placed in an oven at 110°C, and the drying time is preferably Be 8h, obtain catalyst;

[0176] 2. Reduction reaction and catalyst

[0177] Take 4g of the condensation product and place it in an ice bath in a 250mL ro...

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Abstract

The invention provides a method for synthesizing diene compounds based on an aldehyde-ketone condensation reaction. The method comprises the following steps: firstly, under the action of a condensation catalyst, performing a condensation reaction on ketone compounds and aldehyde compounds to obtain condensation products; then, under the action of a reduction catalyst, performing a reduction reaction on the condensation products obtained in the previous step to obtain reduction products; under the action of a catalyst, performing a dehydration reaction on the reduction products obtained in theprevious step to obtain the diene compounds. According to the method, ketone, aldehyde as well as homologues of ketone and aldehyde which are cheap and easy to obtain can be used as raw materials forsynthesizing the diene compounds such as butadiene, piperylene as well as homologues of butadiene and piperylene, experimental conditions are mild, the operation is simple, and a large-scale synthesisprospect is achieved.

Description

technical field [0001] The invention belongs to the technical field of diene synthesis, in particular to a method for synthesizing diene compounds based on aldehyde-ketone condensation reaction. Background technique [0002] Diene compounds, the general formula is C n h (2n-2) , are unsaturated hydrocarbons, hydrocarbon compounds containing two carbon-carbon double bonds. According to the relative position of the two double bonds in the molecule, it can be divided into: cumulative dienes, two double bonds in the molecule are connected to the same carbon atom; isolated dienes, two double bonds in the molecule are separated by more than one single bond Open; conjugated dienes, two double bonds in the molecule are separated by a single bond. Among them, the number of cumulative diolefins is very small, and the properties of isolated diolefins are similar to those of general olefins. Conjugated dienes are the most important and have some properties different from ordinary ol...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C11/167C07C11/20C07C11/12C07C1/24C07C31/20C07C29/143C07C49/17C07C45/75
CPCC07C1/24C07C29/143C07C45/75C07C2529/85C07C2531/02C07C2523/28C07C2527/188C07C2529/04C07C2523/20C07C49/17C07C31/207C07C11/167C07C11/20C07C11/12
Inventor 祁彦龙白晨曦崔龙代全权董巍
Owner CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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