Amplification-effect-free continuous flow synthesis process of tert-butyl peroxy-2-ethylhexyl carbonate

Abstract

The present invention provides an amplification-effect-free continuous flow synthesis process of tert-butyl peroxy-2-ethylhexyl carbonate. According to the synthesis process, tert-butyl hydroperoxide,an alkali liquid and 2-ethylhexyl chloroformate are used as raw materials and are continuously and sequentially subjected to an alkalization reaction, an esterification reaction and a quenching stepto obtain the tert-butyl peroxy-2-ethylhexyl carbonate; and the synthesis process is performed in an integrated continuous flow reactor, the reaction raw materials such as the tert-butyl hydroperoxide, the alkali liquid and the 2-ethylhexyl chloroformate are continuously added into the material inlet of the integrated continuous flow reactor, and the tert-butyl peroxy-2-ethylhexyl carbonate is continuously obtained from the material outlet of the integrated continuous flow reactor, wherein the amplification effect does not exist, and the total reaction time is less than or equal to 180 s. Compared with the traditional production process, the synthesis process of the present invention has advantages of substantially improved temperature, substantially shortened total reaction time, no amplification effect, stable product index and good reproducibility.

Description

technical field [0001] The invention relates to the field of chemistry, in particular to a continuous flow synthesis process of peroxy-2-ethylhexyl tert-butyl carbonate. Background technique [0002] Peroxyesters are important organic peroxides, such as tert-butyl peroxy-2-ethylhexyl carbonate, cumyl peroxyneodecanoate, and peroxyneodecanoate-1,1,3,3- tetramethyl butyl ester. Peroxyester is a low-temperature initiator of free radical polymerization, widely used in polyethylene (LDPE), polyvinyl chloride (PVC), polystyrene (PS), styrene copolymer (such as, ABS), polymethacrylic acid ester (PMMA) and polyvinyl acetate (PVAc) and other production areas. At the same time, it is also a high-temperature curing agent for unsaturated polyester. [0003] Since Baeyer and Villiger reported the preparation of the first peroxyester in 1901, many peroxyester products have come out, and the preparations from laboratory scale to industrial scale have been reported. At present, generall...

AI Technical Summary

Problems solved by technology

[0016] Although a small amount of processes for the continuous preparation of TBEC have been developed, the problems in the existing processes are: first, there is inevitably an amplification effect, which brings many uncertainties to further industrial applications. It is deterministic and greatly affected by the scale of production. When the process with amplification effect is scaled up to industrialization, it needs to be scaled up multiple times. Each scale-up process must re-adjust and optimize the process conditions and parameters, for example, adjust according to production needs. When the production volume is high, it will involve the amplification process. Every time the production volume is adjusted, the process conditions and parameters need to be re-adjusted and optimized, which will greatly consume manpower, material resources and project development time; the scale-up effect is greatly affected by the production scale. , will change with the change of production volume and have no regularity. In industrial production, even if the process conditions and parameters are adjusted in place, if the production scale of the product is changed, the process conditions and parameters need to be re-adjusted and optimized, and the production process lacks flexibility; At the same time, the large and uncertain amplification effect will affect the stability and reliability of the process, and the slight fluctuations in process conditions and parameters may greatly affect the product quality, making the product quality unstable and difficult to control; in addition, this will also affect the production process. Potential security risk

[0017] Second, some continuous processes cannot react completely in a short period of time, and require a longer reaction time to increase the conversion rate, resulting in a decrease in production efficiency

[0018] Third, some continuous processes use stirred reactors, which still contain a large amount of organic peroxide-based reaction mixture, which can lead to a possible exotherm despite the presence of means to dissipate the heat of reaction Hazard of reaction (e.g. decomposition)

As long as there is an amplification effect, no matter how big or small the magnitude is, it will bring many disadvantages to the industrial application of the process in the future. Step-by-step scale-up method, and in order to obtain results consistent with the laboratory scale, the process conditions and parameters must be re-adjusted and optimized each time during the scale-up process, which will greatly consume manpower, material resources and project development time; even with multiple step-by-step Amplification, because the amplification effect is uncertain and the range of change is too large, it may eventually lead to failure to achieve good results on the laboratory scale after amplification; because the amplification effect is greatly affected by the production scale, it will change with the change of production volume and has no Regularity, in industrial production, even if the process conditions and parameters are adjusted in place, if the production scale of the product is changed, the process conditions and parameters need to be re-adjusted and optimized, and the production process lacks flexibility; at the same time, the greatly uncertain amplification effect will affect the process. Stability and reliability, resulting in unstable product quality and difficult to control; in addition, this will also bring potential safety risks to the production process

[0022] Chinese patents CN 101631772, CN 101641326 and document Chem.Eng.Process.2013,70,217-221 all report continuous methods that can be used to prepare TBEC. These continuous methods have all used or partially used stirred reactors, which lead to: one. The stirred reactor used still has the characteristics of a batch device, so there is a magnification effect

The second is that due to the existence of such "intermittent" factors, there will be "stays" in the process, the process is still an unsteady process, not a continuous flow process, and there are still fluctuations and uncertainties in the production (synthesis) process and product quality

The third is that the reactor still contains a large amount of organic peroxide based reaction mixture which, despite the presence of means for dissipating the heat of reaction, can lead to the danger of possible exothermic reactions such as decomposition

Fourth, commonly used mechanical stirrers may not provide optimal mixing of the reaction phases, especially if the phases are immiscible

[0023] As can be seen from the prior art, the existing synthesis techniques of tert-butyl peroxy-2-ethylhexyl carbonate all have different degrees of amplification effects, which will consume a lot of manpower and material resources and have many uncertainties when scaling up to industrialization. There are also problems with process reliability after amplification, resulting in unstable product quality and difficult control; at the same time, the production process lacks flexibility and has potential safety risks; in addition, due to the low reaction temperature, the total reaction time is too long and the yield Not high, reducing production efficiency, which increases the difficulty of industrialization

The inability to achieve mass production limits its application

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