Method for synthesizing cyclohexanone dimer by continuous catalytic reaction and distillation

Abstract

The invention discloses a method for synthesizing cyclohexanone dimer by continuous catalytic reaction and distillation. The method comprises the following steps that: a catalytic reaction and distillation device shown in a figure is adopted, and cyclohexanone enters the a tower from the middle part of the tower; a cyclohexanone dimer and water azeotropic mixture obtained by the condensation of overhead vapor is subjected to continuous low layer resultant water separation in a water knockout vessel, and the upper layer cyclohexanone flows into the top of the tower; and tower bottom residue isheated by a reboiler, the temperature of the residue is controlled to be 250 to 280 DEG C, and 60 to 90 mass percent cyclohexanone dimer can be obtained from liquid discharged from the bottom of the tower. The method adopts continuous catalytic reaction and distillation technology and removes water in products away from a reaction field in time, thereby promoting a reaction to move toward the direction of the formation of the cyclohexanone dimer; meanwhile, the method separates the products of the reaction from a stripping section at the lower part to further eliminate the opportunity for theproducts of the reaction to contact a catalyst, thereby improving the selectivity of the cyclohexanone dimer, ensuring continuous reaction, high production efficiency and high selectivity of the cyclohexanone dimer, and facilitating industrial production.

Description

technical field [0001] The invention relates to a compound synthesis method, in particular to a method for continuously catalytic reaction rectification to synthesize cyclohexanone dimer. Background technique [0002] Ortho-phenylphenol (OPP) is an important chemical product, which is widely used in anticorrosion, flame retardant, disinfection and other fields. The production process of OPP with good prospects widely studied at present is a two-step method of dehydration and dehydrogenation of cyclohexanone, that is, cyclohexanone is first dehydrated under the action of a dehydration catalyst to form a dimer of cyclohexanone, and then the dimer is dehydrated under the action of a dehydrogenation catalyst. Under the action of dehydrogenation to generate OPP. The process can be expressed as follows: [0003] [0004] Wherein 2-(1-cyclohexenyl) cyclohexanone (I) and 2-cyclohexylene alkyl cyclohexanone (II) are isomers, all are dimers of cyclohexanone, and it is not necessa...

AI Technical Summary

Problems solved by technology

The problem with this method is that most resins have an upper limit temperature, which is easy to deactivate, and the reaction needs to be operated under reduced pressure, which increases the cost of power

Although the solid catalyst does not produce a large amount of waste water, the reaction is slow and the dimer yield is low because the acidity and alkalinity of the solid catalyst is not as good as that of the inorganic acid and base.

Although the use of alumina can improve the conversion rate of cyclohexanone and the yield of dimer, the catalyst is easily deactivated and inhibits the occurrence of positive reaction because it is placed in the mixed solution to absorb water, so it needs to be calcined at a higher temperature. reuse

[0008] The above reports using inorganic acids or alkalis and resins all react under stirring and heating in a reactor. Because the concentration of the reactants is high and fully in contact with the catalyst, and the catalyst is strong in acid or alkalinity, the reaction rate is fast, but the reaction selectivity Low; after changing to a solid catalyst with weaker acidity and alkalinity, the catalyst is easily deactivated; the gas-solid or liquid-solid form is used to react in a tubular reactor, and the one-way yield is not ideal

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