Propane acrylonitrile

Propane Acrylonitrile Acrolein, Acrylic acid Pilot plant... 

The addition of active methylene compounds (ethyl malonate, ethyl aoeto-acetate, ethyl plienylacetate, nltromethane, acrylonitrile, etc.) to the aP-double bond of a conjugated unsaturated ketone, ester or nitrile In the presence of a basic catalyst (sodium ethoxide, piperidine, diethylamiiie, etc.) is known as the Michael reaction or Michael addition. The reaction may be illustrated by the addition of ethyl malonate to ethyl fumarate in the presence of sodium ethoxide hydrolysis and decarboxylation of the addendum (ethyl propane-1 1 2 3-tetracarboxylate) yields trlcarballylic acid ... 

The reaction of cyclohexene with the diazopyruvate 25 gives unexpectedly ethyl 3-cyclohexenyl malonate (26), involving Wolff rearrangement. No cyclo-propanation takes place[28]. 1,3-Dipolar cycloaddition takes place by the reaction of acrylonitrile with diazoacetate to afford the oxazole derivative 27[29]. Bis(trimethylstannyl)diazomethane (28) undergoes Pd(0)-catalyzed rearrangement to give the A -stannylcarbodiimide 29 under mild conditions[30]. 

Numerous patents have been issued disclosing catalysts and process schemes for manufacture of acrylonitrile from propane. These include the direct heterogeneously cataly2ed ammoxidation of propane to acrylonitrile using mixed metal oxide catalysts (61—64). 

A two-step process involving conventional nonoxidative dehydrogenation of propane to propylene in the presence of steam, followed by the catalytic ammoxidation to acrylonitrile of the propylene in the effluent stream without separation, is also disclosed (65). 

Because of the large price differential between propane and propylene, which has ranged from 155/t to 355 /1 between 1987 and 1989, a propane-based process may have the economic potential to displace propylene ammoxidation technology eventually. Methane, ethane, and butane, which are also less expensive than propylene, and acetonitrile have been disclosed as starting materials for acrylonitrile synthesis in several catalytic process schemes (66,67). 

Propane-propylene Close-hoihng Acrylonitrile Alternative to simple distillation, adsorption... 

Carbon monoxide, propylene, propane, hydrogen cyanide, acrylonitrile, acetonitrile NOj from by-product incinerator... 

V-Sb-oxide based catalysts show interesting catal)dic properties in the direct synthesis of acrylonitrile from propane [1,2], a new alternative option to the commercial process starting from propylene. However, further improvement of the selectivity to acrylonitrile would strengthen interest in the process. Optimization of the behavior of Sb-V-oxide catalysts requires a thorough analysis of the relationship between structural/surface characteristics and catalytic properties. Various studies have been reported on the analysis of this relationship [3-8] and on the reaction kinetics [9,10], but little attention has been given to the study of the surface reactivity of V-Sb-oxide in the transformation of possible intermediates and on the identification of the sxirface mechanism of reaction. 

Ammonia also reacts with the acrolein intermediate, via the formation of an imine or possibly oxime intermediate which transforms faster to the acrylonitrile than to the acrylamide intermediate. This pathway of reaction occurs at lower temperatures in comparison to that involving an acrylate intermediate, but its relative importance depends on the competitive reaction of the acrolein intermediate with the ammonia species and with catalyst lattice oxygens. NH3 coordinated on Lewis sites also inhibits the activation of propane differently from that absorbed on Brsurface reaction network in propane ammoxidation. 

In the present chapter, we report about an inveshgahon of the catalyhc performance of rahle-type V/Sb and Sn/V/Sb/Nb mixed oxides in the gas-phase ammoxidation of n-hexane. These catalysts were chosen because they exhibit intrinsic mulhfunctional properties in fact, they possess sites able to perform both the oxidahve dehydrogenahon of the alkane to yield unsaturated hydrocarbons, and the allylic ammoxidahon of the intermediate olefins to the unsaturated lutriles. These steps are those leading to the formahon of acrylonitrile in propane ammoxidahon. The SnW/Sb/(Nb)/0 system is one of those giving the best performance in propane ammoxidahon under hydrocarbon-rich condihons (8,9). 

ETHYLENE GLYCOL ETHYL MERCAPTAN DIMETHYL SULPHIDE ETHYL AMINE DIMETHYL AMIDE MONOETHANOLAMINE ETHYLENEDIAMINE ACRYLONITRILE PROPADIENE METHYL ACETYLENE ACROLEIN ACRYLIC ACID VINYL FORMATE ALLYL CHLORIDE 1 2 3-TRICHLOROPROPANE PROPIONITRILE CYCLOPROPANE PROPYLENE 1 2-DICHLOROPROPANE ACETONE ALLYL ALCOHOL PROPIONALDEHYDE PROPYLENE OXIDE VINYL METHYL ETHER PROPIONIC ACID ETHYL FORMATE METHYL ACETATE PROPYL CHLORIDE ISOPROPYL CHLORIDE PROPANE... 

Another way to work in transient conditions is to stop suddenly (or conversely to instantaneously introduce) one of the reactants, in order to destabilize the system and to enhance the concentration of labile species. With this method, for example, Poignant et al. studied the DeNO. reaction mechanism on a H—Cu-ZSM-5 catalyst, using propane or propene as reducing agents. The introduction of 2000 ppm of hydrocarbon in a flow of NO (2000 ppm) + 5% 02 allowed to evidence the formation of acrylonitrile, which behaved as an intermediate. Its reactivity with NO+ species constituted a fundamental point to describe a detailed SCR mechanism for NO removal on zeolitic compounds [137],... 

The catalytic behavior of Fe-MTW zeolites in the direct ammoxidation of propane was investigated. The obtained catalytic results are compared with behavior of Fe-silicalite catalysts whose activity in propane ammoxidation was recently published. It was found that Fe-MTW catalysts exhibit the similar activity as Fe-silicalites but the selectivity to acrylonitrile was substantially lower. On the other hand, Fe-MTW catalysts produce higher amount of propene and have better acrylonitrile-to-acetonitrile ratio. 

The increasing volume of chemical production, insufficient capacity and high price of olefins stimulate the rising trend in the innovation of current processes. High attention has been devoted to the direct ammoxidation of propane to acrylonitrile. A number of mixed oxide catalysts were investigated in propane ammoxidation [1]. However, up to now no catalytic system achieved reaction parameters suitable for commercial application. Nowadays the attention in the field of activation and conversion of paraffins is turned to catalytic systems where atomically dispersed metal ions are responsible for the activity of the catalysts. Ones of appropriate candidates are Fe-zeolites. Very recently, an activity of Fe-silicalite in the ammoxidation of propane was reported [2, 3]. This catalytic system exhibited relatively low yield (maximally 10% for propane to acrylonitrile). Despite the low performance, Fe-silicalites are one of the few zeolitic systems, which reveal some catalytic activity in propane ammoxidation, and therefore, we believe that it has a potential to be improved. Up to this day, investigation of Fe-silicalite and Fe-MFI catalysts in the propane ammoxidation were only reported in the literature. In this study, we compare the catalytic activity of Fe-silicalite and Fe-MTW zeolites in direct ammoxidation of propane to acrylonitrile. 

In the direct ammoxidation of propane over Fe-zeolite catalysts the product mixture consisted of propene, acrylonitrile (AN), acetonitrile (AcN), and carbon oxides. Traces of methane, ethane, ethene and HCN were also detected with selectivity not exceeding 3%. The catalytic performances of the investigated catalysts are summarized in the Table 1. It must be noted that catalytic activity of MTW and silicalite matrix without iron (Fe concentration is lower than 50 ppm) was negligible. The propane conversion was below 1.5 % and no nitriles were detected. It is clearly seen from the Table 1 that the activity and selectivity of catalysts are influenced not only by the content of iron, but also by the zeolite framework structure. Typically, the Fe-MTW zeolites exhibit higher selectivity to propene (even at higher propane conversion than in the case of Fe-silicalite) and substantially lower selectivity to nitriles (both acrylonitrile and acetonitrile). The Fe-silicalite catalyst exhibits acrylonitrile selectivity 31.5 %, whereas the Fe-MTW catalysts with Fe concentration 1400 and 18900 ppm exhibit, at similar propane conversion, the AN selectivity 19.2 and 15.2 %, respectively. On the other hand, Fe-MTW zeolites exhibit higher AN/AcN ratio in comparison with Fe-silicalite catalyst (see Table 1). Fe-MTW-11500 catalyst reveals rather rare behavior. The concentration of Fe ions in the sample is comparable to Fe-sil-12900 catalyst, as well as... 

Fe-MTW catalysts exhibit activity in the direct ammoxidation of propane after steam pretreatment, but the selectivity to demanded product, acrylonitrile, is substantially lower in comparison with Fe-silicalite catalyst. On the other hand, the Fe-MTW catalysts reach the better AN/AcN ratio, it means that they produce less undesirable byproduct, as is acetonitrile. 

PETROX An ammoxidation process for making acrylonitrile from propane or propylene. Developed by BOC Group and partially piloted in New Jersey. 

Most industrially desirahle oxidation processes target products of partial, not total oxidation. Well-investigated examples are the oxidation of propane or propene to acrolein, hutane to maleic acid anhydride, benzene to phenol, or the ammoxidation of propene to acrylonitrile. The mechanism of many reactions of this type is adequately described in terms of the Mars and van Krevelen modeE A molecule is chemisorbed at the surface of the oxide and reacts with one or more oxygen ions, lowering the electrochemical oxidation state of the metal ions in the process. After desorption of the product, the oxide reacts with O2, re-oxidizing the metal ions to their original oxidation state. The selectivity of the process is determined by the relative chances of... 

Aralaguppi, M.I., Jadar, C.V., and Aminabhavi, T.M. Density, viscosity, refractive index, and speed ofsound in binary mixtures of acrylonitrile with methanol, ethanol, propan-l-ol, butan-l-ol, pentan-l-ol, hexan-l-ol, heptan-l-ol, and butan-2-ol, J. 

In the raw materials area, the trend for substitution of paraffin for olefin or aromatic feedstocks is well known. Thus, processes are being developed using butane or pentane instead of benzene for maleic anhydride, and propane instead of propylene for acrylonitrile. 

V-containing silicalite, for example, has been shown to have different catalytic properties than vanadium supported on silica in the conversion of methanol to hydrocarbons, NOx reduction with ammonia and ammoxidation of substituted aromatics, butadiene oxidation to furan and propane ammoxidation to acrylonitrile (7 and references therein). However, limited information is available about the characteristics of vanadium species in V-containing silicalite samples and especially regarding correlations with the catalytic behavior (7- 6). 

One of the most important challenges in the modern chemical industry is represented by the development of new processes aimed at the exploitation of alternative raw materials, in replacement of technologies that make use of building blocks derived from oil (olefins and aromatics). This has led to a scientific activity devoted to the valorization of natural gas components, through catalytic, environmentally benign processes of transformation (1). Examples include the direct exoenthalpic transformation of methane to methanol, DME or formaldehyde, the oxidation of ethane to acetic acid or its oxychlorination to vinyl chloride, the oxidation of propane to acrylic acid or its ammoxidation to acrylonitrile, the oxidation of isobutane to... 

Recently, amorphous high surface area vanadium aluminium oxynitrides have been reported as active catalysts for propane ammoxidation to yield acrylonitrile (AC) at atmospheric pressure. Optimal performance was achieved at 500°C using a C3Hg 02 NH3 molar ratio of 1.25 3 1 (see Tables 4 and 5). The space time yields of these catalysts have been reported to be much higher than for other catalysts reported in the literature. 

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