4-Chloro-3,5-Dimethylphenol CAS 88-04-0

License GB1240829A states the method of using copper chloride dihydrate (hereinafter described as copper chloride) as a catalyst to synthesize 4-chloro-3,5- dimethylphenol by oxidative chlorination. Embrace GLC instrument to evaluate response lead to this patent, the outcome reveals 3, as well as the conversion rate of 5-dimethylphenol reaches more than 97%, and PCMX selectivity can reach more than 93%. Yet this approach is that the driver ratio that makes use of allows, adds a huge quantity of water in the response procedure, has actually lowered response performance, is unfavorable for industrialization, as well as does not assess the true return of response.

Japanese Patent Laid-Open No. 59-5132 states utilizing divalent copper salt as a stimulant, hydrogen peroxide as an oxidizing representative, and making use of hydrochloric acid as the oxychlorination of 3,5-xylenol as a chlorine resource in the system of a natural solvent to manufacture 4-chloro -3,5- Dimethylphenol method. However, from the experimental information supplied by the innovator, the conversion rate and selectivity using this technique are all very reduced, and also the highest possible theoretical return (conversion price * selectivity) acquired is just 79.3, which does not have the value of industrial promotion, and also Organic solvents are required.

The applicant when proposed in Chinese license application 201110084533.9 a technological plan of using divalent copper salt and chlorine-containing not natural materials as a catalytic system to get 4-chloro-3,5- dimethylphenol by oxidative chlorination. The actual yield of the reaction is not discussed in this development.

Although the results of the above-mentioned innovation applications all show that the oxychlorination response using oxygen as the oxidant can acquire really high selectivity (greater than 90%) under the condition of high conversion price (more than 90%). Yet unexpectedly, the innovator of the present application discovers by numerous examinations, makes use of prior technique to manufacture PCMX, when making use of recrystallization, or distillation technique is executed to item when cleansing, the item real yield (concerning 70%) of acquired is far less than The academic return of the response (about 96%). The above speculative outcomes were all gauged under the conditions of gas chromatography. After many repetitive researches, it is ultimately discovered that the above-mentioned oxychlorination results are spotted by GC chromatography, and also the gotten outcomes drift substantially from the actual outcomes. Main reason is that in above-mentioned oxychlorination process, in between the PCMX that creates, and also in between PCMX as well as basic material MX, combining response can happen, creates the ether dimer of high boiling point. This dimer can be quickly found by high pressure liquid chromatography (HPLC). Due to the fact that the boiling point of dimer is high, GC can not discover, as well as makes its result seriously differ actual result. Its response formula, such as:

Preparation of 4-Chloro-3,5- Dimethylphenol.

As a result of the existence of dimerization, the yield of PCMX is considerably minimized. When the conversion rate gets to regarding 99%, the real selectivity of PCMX is just about 80%, and also the dimer in the reaction product gets to more than 10%. Simultaneously, creator locates by additional study, this dimerization reaction has large relation with the conversion price of MX, without delay MX conversion price can not take place when fairly reduced, yet after MX conversion rate gets to a certain level, dimerization reaction Began to accomplish, and now the dimer by-product quantity significantly boosted, and also the dimer was hard to turn around.

As a result, it is essential to make improvements to existing preparation innovation, to prevent the generation of dimer, properly boost the real conversion price of PCMX.