The preparation technology of chloro-cyclohexane under nitrogen protection
Technical field
The invention belongs to the synthesis technique of organic chemical industry's product, a kind of specifically novel process of safety preparation chlorocyclohexane.
Background technology
Chlorocyclohexane is a kind of basic raw material of organic synthesis, also is a kind of important fine chemical product.It is mainly used in the intermediate of products such as rubber anti-chark agent CTP, medical artane, agricultural chemicals cyhexatin; Also can be used for the polyurethane foam catalyst n, N-dimethylcyclohexylamine, rust-preventive agent etc. synthetic.
In numerous chlorocyclohexane preparation methods, the hexanaphthene light chlorination process has overcome the shortcoming of hexalin hydrogenchloride method of substitution, hexanaphthene chlorine method of substitution, tetrahydrobenzene hydrogenchloride additive process, low because of its temperature of reaction, speed of response is fast, adopts light source to avoid plurality of advantages such as catalyst contamination as initiator and had an optimistic view of by the entrepreneur.Patent 200410041630.X adopts reactor and rectifying tower coupled technology to improve transformation efficiency, improves selectivity on original basis.But because the inlet of hexanaphthene and chlorine has just begun reaction all at reaction zone when material also has little time to mix, because the part exists chlorine gas concentration too high, so still there is the drawback of consecutive chlorination reaction.In addition, just there is safety problem in original hexanaphthene light chlorination process, if reactor and rectifying tower are coupled, tower still temperature can reach 140~150 ℃, has more increased unsafe factor.
Summary of the invention
The object of the present invention is to provide that a kind of chlorination selectivity is good, cyclohexane conversion is high and the hexanaphthene light chlorination process of good operation safety prepares the method for chlorocyclohexane.
The present invention is achieved in that
Chlorine and nitrogen is 1:(0.5~1 by volume) carry out pre-mixing, gas mixture feeds continuously from the side mouth of the reactor lower part amount of chlorine with 70~80kg/h, and hexanaphthene feeds from the reactor bottom port continuously with the speed of 320~340L/h.The bottom of reactor is the mixing of materials district, and hexanaphthene and chlorine nitrogen mixed gas arrive reactor top through the thorough mixing of mixing zone, and the initiation light source is arranged here, are the reaction zones of reactor.Under the effect of certain temperature and initiation light source, chlorine and hexanaphthene react rapidly, generate chlorocyclohexane, with unreacted hexanaphthene from vertical discharger track overflow, enter crude steam kettle continuously and carry out continuous still battery, remove most of hexanaphthene, form the crude product chlorocyclohexane.The crude product chlorocyclohexane is squeezed into rectifying still again and is purified, and obtains the high-purity chloro hexanaphthene.
Advantage of the present invention mainly is presented as:
1. chlorine enters before the reactor, uses nitrogen dilution, and the uniform distribution of chlorine in hexanaphthene played pre-dispersed effect.
2. enter the nitrogen of reactor with chlorine,, in reactor, reactive system has been played provide protection, effectively prevented the generation of explosion hazard, do not have side reaction again and take place as rare gas element.
3. adopt the mode of underfeed, make hexanaphthene and chlorine before reaction, sufficient mixing time and space are arranged, effectively prevented the consecutive chlorination reaction, ensured the selectivity of chlorocyclohexane.
4. after chlorocyclohexane generates, in time overflow from overflow spout, short in the reaction zone residence time, effectively prevented the consecutive chlorination reaction.
5. the mode that adopts simple distillation and smart distillation to engage in the thick steaming stage, steams a large amount of hexanaphthenes with lower temperature, carries out reuse.Steam the stage in essence, obtain the high purity chlorocyclohexane, accomplished reasonable energy utilization, improve the purity of chlorocyclohexane with underpressure distillation.
Description of drawings
Accompanying drawing 1 is a process flow sheet
Accompanying drawing 2 is the reactor synoptic diagram
Embodiment:
Below in conjunction with embodiment the present invention is elaborated.
Feed hexanaphthene from the reactor bottom port continuously with the speed of 320~340L/h, open steam valve and make the temperature of reactor rise to 50-60 ℃.Chlorine and nitrogen are 1:(0.5~1 by volume) mixes the back and feed continuously from reactor bottom side mouth, the adjusting flow valve, the feeding speed that makes chlorine is 70~80kg/h.Chlorine carries out thorough mixing at the mixing zone and the hexanaphthene of reactor lower part behind nitrogen dilution, arrive the reaction zone (reactor top) that causes light source is housed, and reacts rapidly under the initiation that causes light, generates chlorocyclohexane.Reaction plays important provide protection to the nitrogen that feeds to security of system.The chlorocyclohexane that generates in time overflows from overflow spout, enters into thick steaming system continuously, the hexanaphthene that steams reuse after condensation, and the purity of the crude product chlorocyclohexane that overflows by equilibration tube can reach about 95%, and the content of polychloride is less than 3%.The crude product chlorocyclohexane is squeezed in the rectifying still by vacuum, carries out underpressure distillation, can get purity greater than 99.5% chlorocyclohexane finished product, and the yield of chlorocyclohexane reaches more than 90%.Front-end volatiles mainly contain hexanaphthene and carry out reuse.In the reaction process, the hydrogen chloride gas of formation absorbs through the last water of multi-stage condensing, forms hydrochloric acid and sells or utilization as by product.