Two phase nitration of chlorobenzene

Cox, P.R.; Strachan, Alec N.

doi:10.1016/0009-2509(71)80014-3

Cited by 30 publications

(28 citation statements)

References 4 publications

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“…Thus, an appropriate mixed acid composition is crucial for establishing the reaction rate and the by-products formation [22,23]. Several authors [24,25] studied the nitration reaction of aromatic compounds like benzene and toluene with mixed acid and concluded it is a second order reaction. The nitronium ion concentration in Eq.…”

Section: Determination Of the Rate Constant For The Benzene Nitrationmentioning

confidence: 99%

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Continuous adiabatic industrial benzene nitration with mixed acid at a pilot plant scale

Quadros

Oliveira

Baptista

2005

Chemical Engineering Journal

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A pilot plant for the continuous adiabatic nitration of benzene was constructed, reproducing the industrial operating conditions, in order to identify the reaction regime prevailing in this industrial process. Important process parameters were tested covering a wide range of operating conditions: reaction temperature (80-135• C), benzene to nitric acid molar feed ratio (0.96-1.15) and stirring speed (390-1700 rpm). The residence time and the sulphuric acid strength were fixed at 2 min and 68%, respectively. The data from a large number of experiments show a good agreement with the results of a mathematical model of the reactor.In the range of operating conditions tested, it was shown that the prevailing reaction regime is the intermediate one (0.3 < Ha < 2). The film model used to predict the mononitrobenzene production according to the intermediate regime achieved a good accuracy. The asymptotic solutions for the fast and slow reaction regimes were compared with the full solution model and it was clearly shown that the last led to improved results. Since the film model is a simple approach to describe the mass transfer with simultaneous chemical reaction, the results achieved confirmed the adequacy of this modelling approach.

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Section: Determination Of the Rate Constant For The Benzene Nitrationmentioning

confidence: 99%

“…The nitric acid may be transferred to the organic phase along with MNB formed, due to its higher solubility in MNB than in benzene [32]. Nevertheless, the maximum rate of nitration in the organic phase is many orders of magnitude less than in the aqueous phase and can be neglected [25,30].…”

Section: Model For the Continuous Pilot Reactormentioning

confidence: 99%

Continuous adiabatic industrial benzene nitration with mixed acid at a pilot plant scale

Quadros

Oliveira

Baptista

2005

Chemical Engineering Journal

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“…27 Omega PT100 (6,9,10, and 13) temperature sensors allow the temperature to be measured in different positions in the pilot plant and these data to be transmitted to the data acquisition system. After the main reactor, the effluent stream goes to a glass/Teflon heat exchanger (17) and a glass separator (18), where it is cooled before being collected in polypropylene reservoirs (19). Swagelok PFA needle valves (7 and 16) allow for the collection of samples from the mixed-acid reactor and from the main reactor.…”

Section: Pilot Plant Design and Operationmentioning

confidence: 99%

“…15,17,18 Nevertheless, the maximum rate of nitration in the organic phase is many orders of magnitude less than the rate in the aqueous phase and can be neglected. 18,19 The side reactions occur simultaneously with the nitration of benzene by the nitronium ion (NO 2 + ). Therefore, the ultimate goal of a benzene nitration process is to produce the nitronium ion solution that will nitrate the aromatic substrate while leaving no nitric acid available to oxidize the aromatic reactant and produce unwanted byproducts.…”

Section: Introductionmentioning

confidence: 99%

Nitrophenols Reduction in the Benzene Adiabatic Nitration Process

Quadros

Castro

Baptista

2004

Ind. Eng. Chem. Res.

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The benzene adiabatic nitration process has been carried out in a pilot plant to enable the study of this reaction under relevant industrial operating conditions, aiming to increase the reaction conversion and selectivity by reducing the nitrophenols. The influence of relevant operating parameters such as the reaction temperature, benzene-to-nitric acid molar feed ratio (F B /F N ), and stirring speed was studied. The operation ranges covered were as follows: reaction temperature, 80-135°C; F B /F N , 0.96-1.15; stirring speed, 360-1700 rpm. The residence time and the sulfuric acid concentration were fixed at 2 min and 68 wt %, respectively. The production of cleaner mononitrobenzene (MNB) requires lower nitration temperatures; higher F B /F N ratios than in current industrial practice; and high stirring speeds, allowing the interfacial area in this liquid-liquid mixture to be increased and the decrease in temperature to be compensated. The results reported here highlight the relevance of combining operating parameters to improve the performance of the reactor. In this study, it was possible to accomplish the same MNB production with a significant reduction in nitrophenols concentration. This work presents results that might be useful for conventional industrial benzene adiabatic nitration plants, to improve the prevention of pollution in this process and allow competitiveness with new plants in fulfilment of environmental law requirements.

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“…To get accurate kinetics of nitration reaction is always difficult. Many kinetic studies of nitration of benzene [9], toluene [10], chlorobenzene [11], and nitrobenzene [12] have been described in the literatures. However, most of them are studied in batch reactors, which could hardly ensure isothermal environment and lack accuracy.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Study and Intensification of Acetyl Guaiacol Nitration with Nitric Acid-Acetic Acid System in a Microreactor

Zhang¹,

Zhang²,

Luo³

2016

J Flow Chem

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Nitration of acetyl guaiacol, one typical aromatic nitration, is highly exothermic and extremely fast. Better control and high efficiency can be achieved in the microreactor due to its enhanced mixing and heat transfer rates. In this study, nitration of acetyl guaiacol was carried out in a microreactor using nitric acid-acetic acid as nitrating agent. The nitration kinetics was first investigated, and a kinetic model was established and revealed good prediction of experimental results at higher temperatures. Effects of molar ratio of nitric acid-acetyl guaiacol, residence time, temperature, and nitric acid concentration on the reaction were studied in detail. Under optimized condition, 90.7% yield of desired product, 5-nitroguaiacol, was achieved with 40% of nitric acid concentration, nitric acid-acetyl guaiacol molar ratio of 2.6, reaction temperature of 120°C, and residence time of 2 min. Compared to traditional batch reactor, microreactor showed the advantages of higher yield and selectivity, much shorter reaction time, and less use of nitric acid.

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Two phase nitration of chlorobenzene

Cited by 30 publications

References 4 publications

Continuous adiabatic industrial benzene nitration with mixed acid at a pilot plant scale

Continuous adiabatic industrial benzene nitration with mixed acid at a pilot plant scale

Nitrophenols Reduction in the Benzene Adiabatic Nitration Process

Kinetic Study and Intensification of Acetyl Guaiacol Nitration with Nitric Acid-Acetic Acid System in a Microreactor

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