Industrial continuous process for preparation of p-tert-butylphenol

Abstract

The invention discloses an industrial continuous process for preparation of p-tert-butylphenol. According to the process, phenol and isobutene are used as raw materials and allowed to pass through a fixed-bed reactor under the action of a catalyst, wherein continuous operation via multiple tandem kettles is carried out in the fixed-bed reactor; phenol is added from a first kettle; isobutene is added in a manner of multi-kettle continuous introduction; a reaction device is directly connected with a rectification device for separation of the raw materials and a product; the raw materials are returned to a catalytic tower for continuous operation; and the product is directly connected with a product storage tank after rectification. The method has the beneficial effects of good selectivity, high conversion rate, high yield, and almost no wastewater during production.

Description

technical field [0001] The invention belongs to the technical field of chemical industry and relates to an industrialized continuous method for preparing tert-butylphenol. Background technique [0002] p-tert-butylphenol is an important raw material of p-tert-phenol formaldehyde resin, widely used in the synthesis of oil-soluble phenolic resin, plasticizer of synthetic rubber, anti-cracking agent, stabilizer of styrene and butadiene, high-grade ink and paint additives, etc. In addition to being a wide range of additives, it is also an intermediate of many high-performance additives used in oil refining, petrochemical and polymer material industries. [0003] The industrial synthesis of p-tert-butylphenol mainly uses phenol and isobutylene as raw materials. The catalytic system first used sulfuric acid as a catalyst, and later extended to other protonic acids or Lewis acids, such as phosphoric acid, boron trifluoride, hydrogen fluoride, trichloro However, this method has di...

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Problems solved by technology

[0003] The industrial synthesis of p-tert-butylphenol mainly uses phenol and isobutylene as raw materials. The catalytic system first used sulfuric acid as a catalyst, and later extended to other protonic acids or Lewis acids, such as phosphoric acid, boron trifluoride, hydrogen fluoride, trichloro Aluminum, etc., but this method has the disadvantages of phenolic water pollution, corrosion equipment, poor product quality, many side reactions, and difficult separation of catalyst and product.

In order to overcome the above shortcomings, the patent US 426083 loads protonic acid or Lewis acid on an inorganic carrier, such as activated clay or acid clay. This method not only improves the utilization rate of isobutene, but also the product does not need to be washed, effectively solving the problem of phenolic water pollution. However, a large amount of catalyst waste residue will be produced during production, which is difficult to handle and is not suitable for large-scale industrial production

Chinese patent CN1572760A introduces a method for synthesizing tert-butylphenol with MTBE as an alkylation reagent. This patent uses a double-tank reactor, which cannot be continuously produced, and MTBE will be used as a by-product of methanol. The methanol generated in the reaction must be gradually removed from the reaction system, otherwise the conversion rate of the reaction is low

Cationic resin is used as the catalyst, the reaction conditions are mild, and there is no corrosion, but there are still problems such as low reaction selectivity, many by-products, and difficult product separation.

[0005] The ratio of isobutene and phenol has a great influence on the composition of the alkylation liquid. Excessive isobutene will lead to a large number of disubstituted products or even multi-substituted products in the final composition of the alkylated liquid. Insufficient isobutene will reduce the conversion rate of phenol , thus seriously affecting the quality of the alkylating liquid, bringing enormous pressure to the separation and purification of the product and the production cost

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