A 4-cyanopyridine continuous evaporation crystallization device and method

Abstract

The invention discloses a device and method for continuous evaporation and crystallization of 4-cyanopyridine, which comprises a pressurized assembly, a connecting pipe and an evaporation reactor. The crystallization temperature of pyridine and the boiling point temperature of other organic solvents. After the pressurization is completed, the heating resistor is used to heat and crystallize the solution part to ensure that only water and other organic solvents are vaporized during the evaporation and crystallization of 4-cyanopyridine. While 4-cyanopyridine is heated and crystallized, water vapor and other organic solvents and part of 4-cyanopyridine are absorbed and re-liquefied by the condensing reflux box, and are dripped and evaporated on the right side of the reactor. The heating resistor performs the evaporation and crystallization operation under normal pressure again, so that 4-cyanopyridine is crystallized and precipitated, and attached to the right inner wall of the evaporation reactor, which simplifies the crystallization operation steps of 4-cyanopyridine and effectively improves the 4-cyanopyridine ‑ The amount of crystals precipitated by cyanopyridine.

Description

A kind of 4-cyanopyridine continuous evaporation and crystallization device and method technical field The present invention relates to evaporative crystallization equipment technical field, particularly a kind of 4-cyanopyridine continuous evaporative crystallization device and methods. Background technique 4-cyanopyridine, its molecular formula is C 6 H 4 N 2 , with a molecular weight of 104.11, is a white to pale yellow needle-like crystal, It has a characteristic odor, is soluble in ethanol, ether and benzene, and is mainly used for pharmaceutical and pesticide intermediate products, which are usually stored In a cool and ventilated warehouse, away from fire and heat sources, it should be stored separately from oxidants, and should not be stored together. Sealed storage, using explosion-proof Type lighting and ventilation facilities, prohibit the use of mechanical equipment and tools that are prone to sparks, and the storage area should be equipped w...

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Problems solved by technology

Store in a sealed environment, use explosion-proof lighting and ventilation facilities, prohibit the use of mechanical equipment and tools that are prone to sparks, and the storage area should be equipped with leakage emergency treatment equipment and suitable containment materials. When the preparation of 4-cyanopyridine is completed, it is usually in In the state of the solution, 4-cyanopyridine is usually crystallized and recovered by evaporative crystallization. In the process of evaporative crystallization, it is difficult to control the evaporation temperature, and other substances in the organic solution can easily make 4-cyanopyridine Simultaneous vaporization, resulting in less crystallization of 4-cyanopyridine crystals

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