Applied Catalysis, A, 106, 143-153 (1993). Reaction Conditions: Pressure =1 atm, temperature = 573 K, benzene/ 1,4-DIPB ratio = 5:1, N2 to feed ratio = 0.2, time on stream = 30 min. In another process, DIPBs were recycled for transalkylation in the reactor containing a single catalyst bed of beta catalyst. This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
<> The air oxidation of cumene (isopropyl benzene) leads to the production of both phenol and acetone, as shown in the following figure.
endobj Transalkylation is isothermal. A small fraction of the cumene is further alkylated to polyisopropylbenzenes (PIPB), which is recovered in distillation and converted back to cumene in the transalkylation reactor. 10 0 obj The kinetic model derived for the reactions can provide the necessary information to scale up the reactor for large scale production in industry. The original route for manufacturing of cumene was by alkylation of benzene in the liquid phase using sulfuric acid as a catalyst, but because of the complicated neutralization and recycling steps required, together with corrosion problems, this process has been largely replaced. Thus, it can be concluded from Fig. The diagram show cumene production from benzene and propylene[/caption] The process The present analysis discusses an industrial process for cumene production. The sample was introduced through a micro syringe into the injector port of the GC. Effect of Space Time on Selectivity of Products and Conversion of 1,4 DIPB. It is hydrolysed with dil acid to give phenol and acetone An alkylation system converts benzene and propylene to cumene. [ Links ], Wang, H. and Zou, Y., Modified beta zeolite as catalyst for fries rearrangement reaction. This suggests that the zeolite framework remains unaffected after the ion exchange process and cerium exchange of beta zeolite. Table 2 Product distribution at various space times. A dosing pump was used to introduce the reactant feed mixture into the reactor. Figure 5 Cumene selectivity as a function of time-on-stream.
The column temperature was initially set at 323K, and then increased to 523 K at a rate of 10 K/min. [ Links ], Bellussi, G., Pazzuconi, G., Perego, C., Girotti, G. and Terzoni, G., Liquid phase alkylation of benzene with light olefins catalyzed by beta zeolite. To prepare phenol, cumene is first oxidised in the presence of air to cumene hydroperoxide. Figure 11 A plot of ln k vs 1/T for determination of the activation energy. The figure shows that the proposed reaction rate expression predicts 1,4-DIPB conversion values quite comparable to the experimental values, having an R2 value of 0.99. Effect of intraparticle diffusional resistance on DIPB conversion over CeB10. ExxonMobil catalysts have successfully produced high-quality cumene from every commercial grade of propylene and its cumene product has been a feedstock to every major Phenol process technology. The activation energy values for various reactions compare well with the values of similar reactions on zeolites obtained by other investigators (Kondamudi and Upadhyayula, 2008).
At low loading of metal ions into the zeolite framework, no diffraction lines corresponding to metal species were observed as at low loading, the cerium ions replace the H+ ions (Tang et al., 2014) and are highly dispersed in the zeolite framework (Garcia et al., 2011). Moreover, the number of acid sites also increases as the peak area increases with Ce exchange. The effect of temperature on product selectivity is shown in Fig.
endobj 7 shows that the maximum selectivity (83.82%) of cumene was obtained at a benzene to 1,4-DIPB ratio of 5:1, beyond this ratio, the isomerisation of 1,4-DIPB seems to increase and hence a decrease in cumene selectivity was observed. TPD profiles show that, in the case of H-beta zeolite, only weak acid sites are present. Organic Process Research and Development, 6, 132-137 (2002). Studies in Surface Science and Catalysis, 105, 1325-1332 (1997). Journal of Chemical Engineering, 114, 39-45 (2005). [ Links ], Reddy, K. S. N., Rao, B. S. and Shiralkar, V. P., Alkylation of benzene with isopropanol with zeolite beta.
1 0 obj [ Links ], Ercan, C., Dautzenberg, F. M., Yeh, C. Y. and Barner, H. E., Mass-transfer effects in liquid-phase alkylation of benzene with zeolite catalysts. It is of industrial demand for the production of high molecular weight hydrocarbons such as cymene and polyalkylated benzene. G) How large a CSTR would be needed to convert 90% of the benzene into cumene if the inlet flow rate of benzene is 10 mol/s, the propylene is fed stoichiometrically, and the total molar concentration in the reactor is 1 mol/L. ExxonMobil’s zeolite catalysts are the heart of the Badger Cumene process.
The filtrate was transferred to a beaker and its volume was made up to about 250 ml by adding distilled water. Sample was first ground thoroughly and then it was mixed with KBr salt and again ground well to make a fine powder, which was then pressed to make a pellet. [ Links ], Krishnan, A. V., Ojha, K., and Pradhan, N. C., Alkylation of phenol with tertiary butyl alcohol over zeolites. Transalkylation of DIPB has also been carried out over large pore zeolites, which proved to be very active catalysts (Pradhan and Rao, 1993). stream The cumene process licensed by Badger uses an extremely low benzene to propylene (B/P) ratio in the alkylator feed and an extremely low benzene to PIPB ratio in the transalkylator feed, resulting in very low equipment cost and fuel consumption. Applying non-linear regression, the model parameters were estimated. These models were tested with the help of the experimental data. The kinetic constants evaluated and tabulated at various temperatures (Table 5) were used to determine the activation energy for cumene synthesis (transalkylation) which was estimated to be 116.53 kJ/mol; for the isomerisation reaction the activation energy was found to be 176.01 kJ/mol by the following equation: Table 5 Kinetic and adsorption constants at different temperature. An alkylation reactor uses ExxonMobil catalyst to convert benzene and propylene to cumene in the liquid phase. The Badger Cumene process is a high yield, high energy efficiency, low environmental impact process that is easy to operate and maintain, allowing for very low production cost. <> The ExxonMobil catalysts are noncorrosive, environmentally inert, and regenerable. [ Links ], Yeh, C. Y., Xu, J., Hillsborough, N. J., Angevine, P. J. and Woodbury, N. J., Process for benzene alkylation and transalkylation of polyalkylated aromatics over improved zeolite beta catalyst. f�qy}z�͛bƙ�E��Y�NJ]n̛�}J����@vc_e��w�'��mW����f��9=������䑒���6��ż���`��#\��/a�W�3aާ~�)De��1�Dғy���^�*��5���*Ù�P���?�J�T�LDU��b����vQ�] Peaks were identified by retention time matching with known standards. Verify your number to create your account, Sign up with different email address/mobile number, NEWSLETTER : Get latest updates in your inbox, Need assistance? The alkylation reaction is exothermic and the alkylation reaction system is staged with intermediate cooling to control the reaction temperature. FTIR of H-beta and Cerium modified beta zeolites. The commercially available H-beta zeolite containing H+ ions was modified with Ce4+ ions.
<> Green Chemistry, 6, 274-279 (2004). The low temperature peak is due to ammonia desorption from the weak acid sites, whereas, the peak at high temperature is due to the desorption of strongly adsorbed ammonia from strong acid sites. © Copyright 2003-2020 Exxon Mobil Corporation. B. and Das, J., Novel catalytic aspects of beta zeolite for alkyl aromatics transformation. About Us | Technologies & Services | Contact Us | Press Room | Legal. The acidity of H-beta zeolite was found to be 0.88 mmol/gm and that of cerium beta zeolite was 1.79 mmol/gm.
Cumene selectivity as a function of time-on-stream. At high loading of cerium (10 wt%), additional peaks related to cerium oxide (2θ = 13.560 and 46.50) were found in zeolite XRD pattern (Thakur et al., 2015). [ Links ], Halgeri, A. The temperature of the injector was set at 493 K during the analyses. Copyright Notice © 2020 Greycells18 Media Limited and its licensors.
[ Links ], Tang, B., Dai, W., Sun, X., Guan, N., Li, L. and Hunger, M., A procedure for the preparation of Ti-Beta zeolitesfor catalytic epoxidation with hydrogen peroxide.
<> Benzene and propylene are compressed together to a pressure of 30 standard atmospheres at 250 °C (482° F) in presence of a catalytic Lewis acid. Cumene (also known as isopropylbenzene) is an organic compound of the aromatic hydrocarbon class. Activity of the modified catalyst was evaluated in the range of temperature 493K-593K, space time 4.2 kg h/kmol-9.03 kg h/k mol and benzene/1,4-DIPB molar ratio 1-15 to maximize the reactant conversion and selectivity of cumene. The peak at 520 cm−1 is characteristic of beta zeolite (Kiri et al., 1994). View highlighted news, events, technical papers and case studies below. 7&:�ƫǖ7~E�*@�'h �ݸS�Ý;��?֡xD�t*]g*��~�|]�i�={c?^A��+�uQɲ.S% &���!e�'O$�~E�ĂЯ�àc5��h�������4�(ƣ��)G@�I��NC�$�7�G�]�{W-�W�{�(��*�61���TEY��5!�T��8��"Df���2L�h�*B���U��ɀb�;�:�����*�(��{����x���-�h�0(Z�2�.Y���. endstream [ Links ], Bakas, S. T. and Barger, P. T., Alkylation/transalkylation process. Phone: + 91-175-2393437; Fax: + 91-175-239300. Figure 10 Experimental vs predicted rate of reaction. <> All website features may not be available based upon your cookie consent elections. E) Why is the temperature of the cooling jacket at the end of the process so different than that at the beginning? Typical diffraction characteristics of BEA topology are observed for both the zeolites indicating the framework structure is well preserved after cerium exchange.
Want a call from us give your mobile number below, For any content/service related issues please contact on this number. [ Links ], Received: ��/�uu����2~���. In the present study, transalkylation of 1,4-diispropylbenzene (DIPB) with benzene in the presence of modified beta zeolite was performed to produce cumene in a fixed bed reactor. US Patent 4375574 A (1983). Catalyst sample (0.1 g) was first degassed at 723 K for 1 h with nitrogen followed by cooling to 273 K temperature. 15 0 obj [ Links ], Pradhan, A. R. and Rao, B. Maximum productivity and profitability. The FTIR spectra of H-beta and cerium exchanged beta zeolite are shown in Fig. Applied Catalysis, A, 181, 347-354 (1999). Various products like aliphatics (propene), benzene, toluene, xylene (C8), cumene, cymene (C10), isomers of DIPB were found.