A kind of method of synthesizing vinyl norbornene

Abstract

The invention discloses a method of synthesizing vinyl norbornene by utilizing a circulating tubular reactor. The method incudes 1) a step of adding an inert organic solvent, cyclopentadiene (CPD) and 1,3-butadiene (BD) into the circulating tubular reactor to synthesize the vinyl norbornene (VNB), returning a part of a reaction solution in the outlet of the reactor into the circulating tubular reactor for continuous reaction, and feeding the rest of the reaction solution into a VNB purifying unit, 2) a step of feeding the rest of the reaction solution in the outlet of the reactor in the step 1) into a light component removing column, and rectifying to obtain the high-purity VNB from the top of the column. A process and a route of the method are simple and reliable. The using amount of the solvent is reduced. The amount of a crude product to the processed is greatly reduced, thus reducing the product purification cost.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a method for synthesizing vinyl norbornene by using a reaction liquid circulation method. Background technique [0002] Vinyl norbornene is an important intermediate for the synthesis of ethylidene norbornene. It can be converted to ethylidene norbornene by isomerization. Ethylidene norbornene, as the preferred third monomer for the synthesis of ethylene propylene diene monomer (EPDM), has many excellent properties, and is currently receiving more and more attention. [0003] Vinyl norbornene is synthesized by Diels-Alder reaction of 1,3-butadiene and cyclopentadiene. However, since both cyclopentadiene and 1,3-butadiene are conjugated dienes, they are dienes and dienophiles crossing each other. Therefore, the reaction process will be accompanied by side reactions such as self-polymerization and copolymerization, which will produce vinyl cyclohexene (VCH)...

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Problems solved by technology

[0008] Chinese patent CN1580015A discloses a method for producing an ethylidene norbornene intermediate. The patent describes that the batch-type reactor is fed once, with benzene or n-hexane as the solvent, and the mass fraction of the reaction material cyclopentadiene solution is 70-80%, the molar ratio of BD / DCPD is (1~2):1, the concentration of the reactants will gradually decrease in the batch reaction, resulting in a decrease in the selectivity and conversion rate of the product VNB; and it is considered to operate under the state of full liquid as much as possible It will be beneficial to this reaction, so it is also proposed to adopt a single-into-single-out tubular continuous reactor, the residence time is 0.25-1h, and the VNB selectivity is only 25.91-36.28%

[0010] Chinese patent CN102123973A discloses a preparation method of ethylidene norbornene, which describes the preparation of high-purity CPD by cracking DCPD with inert diphenyl ether as a solvent in a tank reactor, but has no effect on the VNB synthesis process. detailed description

Since the single-pass VNB yield is not high, the solvent accounts for more than half of the proportion, which makes the cost of product refining and solvent recycling very high

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