The method of obtaining alpha generatingcapacity of ethylbenzene
The invention relates to a method for generatingcapacity of ethylbenzene oxidation of the latter with oxygen in the presence of a ternary catalyst system comprising a bis-acetylacetonate Nickel, electron-donor complexing compound, for example an alkali metal stearate - sodium or lithium, N-organic-2, hexamethylphosphorotriamide and phenol concentration (0,5-3,0)10-3mol/l-generatingcapacity is used to obtain propylene oxide, the world production of which is more than 106tons per year, and 44% of production based on the use of EVP as epoxidised agent. Effect: increase the degree of conversion of EB in the EVP to 35%, increase in the content of the target product in the reaction mixture of 27%. table 1.
The invention relates to a process for the production of hydroperoxides of alkylaromatic hydrocarbons, specifically to methods for-generatingcapacity (EVP) of ethylbenzene (EB).
-Generatingcapacity used for obtaining propylene oxide, the world production of which is more than 106tons per year, and 44% of production based on A method of obtaining the EVP oxidation of ethylbenzene, based on the application as catalyst bis-acetylacetonate Nickel Ni(AcAc)2[L. A. Mosolov, L. I., Matienko, I. P. Skybed. Kinetics and catalysis, 1987, T. 28, No. 2, S. 484]. The method provides for obtaining the target product with a selectivity of about 85% at conversion degrees not exceeding 6%, so it is the process cannot be considered effective.
A method of obtaining the EVP of ethylbenzene in the presence of a binary catalyst system containing in addition to Ni(AcAc)2the phase transfer catalyst macrocyclic polyether 18-crown-6 (S) [L. I., matienko, L. A. Mosolov, I. P. Skybed. News of Academy of Sciences, series of chemical, 1994, No. 8, S. 1406]. This catalytic system provides a high (>90%) selectivity of oxidation, however, it is achieved by the conversion rate, not exceeding 4%. The application of this method is also limited because of the high toxicity of the crown ether.
Known methods of oxidation of ethylbenzene in the EVP in which the second component of the catalytic system used Tetramethylammonium [L. I., matienko, L. A. Mosolov, I. P. Skybed. News of Academy of Sciences, series of chemical, 1994, No. 8, S. 1412] or hexaphosphate 1-n-butyl-3-methylimidazole [R. Alkantara et al. Appl. Catal. A: General, 2001, v.218, RV 269]. Thus the high selectivity of riodic to the reduction of the effective concentration of the catalytically active complex.
Closest to the proposed technical solution is the way of the oxidation of ethylbenzene in generatingcapacity in the presence of two-component catalytic system containing, along with the bis-acetylacetonate, Nickel (component 1), donor complexing compound (component 2), which can be used are metal salts of constant valency, such as stearates, sodium or lithium amides, such as hexamethylphosphorotriamide (GMFA), pyrrolidone derivatives such as N-organic-2 (MP) [L. A. Mosolov, L. I., matienko. WPI. The USSR Academy of Sciences, series of chemical, 1981, No. 4, S. 731]. The main disadvantage of this method is the reduction in the rate of oxidation due to the deactivation of a two-component catalyst system in the reaction. As a result of this acceptable selectivity 85-87% is achieved at low degrees of conversion, the components of 12-14%, which does not allow to obtain the pure product in high yield.
The objective of the invention is to increase the efficiency of oxidation of ethylbenzene in generatingcapacity through the use of a catalytic system, which would increase the degree of conversion of the original product while maintaining the high selectivity of the process.
Wait catalytic system, contains, along with the bis-acetylacetonate Nickel and donor complexing compound, optionally phenol (component 3). Analysis of the kinetic regularities showed that the introduction of the phenol in the reaction system directly at the beginning of the reaction system formed more active, including phenol triple catalytic complexes, which does not lose activity in the reaction. Ternary complexes inhibit the formation of by-products, helping to increase the selectivity of oxidation, do not decompose under the reaction conditions and increase the rate of formation of generatingcapacity, which is not reduced until the maximum concentration of the target product. The proposed method allows to carry out the oxidation with high selectivity, to significantly improve the conversion rate and concentration-generatingcapacity in the reaction mixture. To obtain a technical result it is essential to have all three components: in the absence of component 1 - bis-acetylacetonate Nickel, is the inhibition of oxidation, and in the absence of electron-donating component 2 Supplement bis-acetylacetonate Nickel phenol, depending on the concentration of poslednego The essence of the method consists in the following. Prepare separate solutions of the components 1, 2 and 3 in ethylbenzene. The concentration of these solutions are selected so that upon subsequent mixing equal volumes of the molar concentration of component 1 - Ni(AcAc)2was 310-3mol/l, molar concentration of electron-donor complexing compounds of component 2 was in the case of alkali metal stearates (3-3,5)10-3mol/l, in the case of MT and HMPA (2-7)10-2mol/l, and the molar concentration of component 3 - phenol was (0,5-3,0)10-3mol/L. Intervals of concentrations of components 1 and 2 correspond to the prototype. With the introduction of phenol in concentrations outside the specified interval, the selectivity and conversion of oxidation are reduced to the level of a prototype and below.
The catalytic system is formed in situ by mixing equal volumes of freshly prepared solutions of components 1, 2 and 3. The oxidation of ethylbenzene with molecular oxygen is carried out in a bubbling reactor type in the absence of diffusion inhibition at a flow rate of oxygen 2 l/h at a temperature of 120C and atmospheric pressure. The reaction time is determined by the maximum molar concentration of the target product, which control will iodomethyl ratio:
where [EVP] - molar concentration of the target product;
[EB] - the change in the molar concentration of ethylbenzene in the oxidation process, which is evaluated by the sum of the resulting products: target product-generatingcapacity and by-products of methylphenylcarbinol, acetophenone and phenol, determined by gas chromatography. As an acceptable level of selectivity take S=85-87%, achieved at the present time when industrial production EVP. The efficiency of the process when the selectivity is estimated by the degree of conversion, which is calculated by the formula:
where [EB]0- initial concentration of ethylbenzene.
The possibility of practical realization of the proposed method and the possibility of obtaining the claimed technical result is illustrated by the following examples.
Example 1. In a glass reactor bubble type placed in 5 ml of freshly prepared solution of ethylbenzene component 1 - Ni(AcAc)2concentration 910-3mol/l, component, 2 - sodium stearate (NaSt) concentration 910-3mol/l and component 3 - phenol concentration 910-3mol/l Concentration of each component temperature 120C and atmospheric pressure. The conversion of EB in the EVP when the selectivity of 85% is 35%, the concentration of the EVP in the reaction mixture is 27%.
Examples 2-8 performed analogously to example 1 and are introduced into the reaction component 2, the concentration of the original solution components 2 and 3 and their concentration in the reaction mixture. In all examples, the concentration of the original solution component 1 - Ni(AcAc)2the ethylbenzene is 9,010-3mol/l, and its concentration in the reaction mixture - 3,010-3mol/L.
In the following table are used in examples 1-8 components 2 and 3 catalytic system, initial solution concentration of components 2 and 3, their concentration in the reaction mixture, and the degree of conversion and the concentration of the target product in reactions mixture characterizing the effectiveness of the proposed method of obtaining the EVP. The results obtained were compared with the results obtained by the prototype method, implemented in a similar situation.
Thus, the proposed method get-generatingcapacity of ethylbenzene in the presence of a ternary catalyst system comprising in addition to the bis-acetylacetonate Nickel and donor complexing compounds, tapologo product in the reaction mixture in the 1.1-1.7 times, and the degree of conversion of the original product 1.2-2.7 times in comparison with the method of the prototype. The greatest efficiency is characterized by the system containing the electron-donor complexing compounds sodium stearate, allowing to increase the concentration of the EVP in the reaction mixture in 1.7 times, and the degree of conversion of the original product - 2.7 times.
Way to obtain-generatingcapacity of ethylbenzene in the presence of a catalytic system comprising bis-acetylacetonate Nickel and donor complexing compound, which is used as a compound selected from the list: sodium stearate or lithium, N-organic-2, hexamethylphosphorotriamide, characterized in that the catalytic system further comprises a phenol at a concentration in the reaction mixture 0,510-3-3,010-3mol/L.