Ethylene derivatives dehydrogenation

Nitrobenzene potassium carbonate Ethylene derivatives by dehydrogenation... 

Different ethylene-derived species, such as vinyl or acetylene, have been observed on other metals. On the (100) surface of iron, for example, the di-<7-bound C2H4 dehydrogenates to acetylene around 200 K, while at about 400 K the triple C=C bond breaks to yield CH and CH2 fragments, which eventually release their hydrogen to form carbidic or even graphitic carbon at elevated temperatures. 

Benzene is alkylated with ethylene to produce ethylbenzene, which is then dehydrogenated to styrene, the most important chemical iatermediate derived from benzene. Styrene is a raw material for the production of polystyrene and styrene copolymers such as ABS and SAN. Ethylbenzene accounted for nearly 52% of benzene consumption ia 1988. 

The pattern of commercial production of 1,3-butadiene parallels the overall development of the petrochemical industry. Since its discovery via pyrolysis of various organic materials, butadiene has been manufactured from acetylene as weU as ethanol, both via butanediols (1,3- and 1,4-) as intermediates (see Acetylene-DERIVED chemicals). On a global basis, the importance of these processes has decreased substantially because of the increasing production of butadiene from petroleum sources. China and India stiU convert ethanol to butadiene using the two-step process while Poland and the former USSR use a one-step process (229,230). In the past butadiene also was produced by the dehydrogenation of / -butane and oxydehydrogenation of / -butenes. However, butadiene is now primarily produced as a by-product in the steam cracking of hydrocarbon streams to produce ethylene. Except under market dislocation situations, butadiene is almost exclusively manufactured by this process in the United States, Western Europe, and Japan. 

Dehydrogenation of the hydrazide derivative 33 with mercuric oxide in the presence of ethylene diamine tetraacetic acid (EDTA) gave 34 and 35 (77AP588). The latter (35) was prepared from a reaction of ester 36 with the appropriate lactam 37 (Scheme 11). 

Methanol dehydrogenation to ethylene and propylene. In some remote ioca-tions, transportation costs become very important. Moving ethane is almost out of the question. Hauling propane for feed or ethylene itself in pressurized or supercooled vessels is expensive. Moving naphtha or gas oil as feed requires that an expensive olefins plant with unwanted by-products be built. So what s a company to do if they need an olefins-based industry at a remote site One solution that has been commercialized is the dehydrogenation of methanol to ethylene and propylene. While it may seem like paddling upstream, the transportation costs to get the feeds to the remote sites plus the capital costs of the plant make the economics of ethylene and its derivatives okay. 

The important derivatives of benzene are shown in Table 8.8. Ethylbenzene is made from ethylene and benzene and then dehydrogenated to styrene, which is polymerized for various plastics applications. Cumene is manufactured from propylene and benzene and then made into phenol and acetone. Cyclohexane, a starting material for some nylon, is made by hydrogenation of benzene. Nitration of benzene followed by reduction gives... 

Styrene. Still another process in which petroleum-derived ethylene serves as a raw material in the production of synthetic polymers is the reaction of ethylene with benzene to produce ethylbenzene, followed by dehydrogenation to styrene. 

The dehydrogenation of l,2-di(10-hydroxy-9-anthryl)ethane 124 afforded dianthronylidene ethane 125 [142], which attracted my attention because it formed crystal phases of unique luminescence properties [144,145], Moreover, reduction of 125 by diphenylhydroxymethyl radicals led to the previously unknown l,2-di(10-hydroxy-9-anthryl)ethylene 126 [142], When the stereochemistry of 126 and its derivatives was to be established by absorption and emission spectroscopy, the cis- and trans-isomers of unsubstituted l,2-di-9-anthrylethylene, i.e., compounds 38a/39a of Section III were needed for spectral comparison. 

Some positional isomers of coralyne have been synthesized and examined for antileukaemic activity,82 and the distribution of salts of coralyne after they have been administered to rodents has been studied.83 Dehydrogenation of canadine to berberrubine (59) can be accomplished in ethylene glycol and hydrochloric acid with palladium or with tris(triphenylphosphinyl)rhodium chloride, the reaction proceeding faster at low temperatures with the latter catalyst.84 Derivatives of 13-methylberberrubine and its analogues have been synthesized, so that they might be screened to find their potential as antitumour agents.85... 

Styrene. Styrene is the largest benzene derivative with annual consumption about 11.5 billion lb in the United States. It is produced mainly by catalytic dehydrogenation of high-purity ethylbenzene (EB) in the vapor phase. The manufacture process for EB is based on ethylene alkylation with excess benzene. This can be done in a homogeneous system with aluminum chloride catalyst or a heterogeneous solid acid catalyst in either gas or liquid-phase reaction. In the past decade, the liquid-phase alkylation with zeolite catalyst has won acceptance. Those processes have advantages of easier product separation, reducing waste stream, and less corrosion. In addition, it produces less xylene due to lower... 

Derivation From ethylene and benzene in the presence of aluminum chloride to yield ethylbenzene, which is catalytically dehydrogenated at 630C to form styrene. 

R.F. Preparation of Ethylbenzene and Substituted Derivatives by Alkylation Using Unpurified Reac- 27. tion Products of Ethylene Prepared by Dehydrogenation of Ethane World Patent WO 96/34843,... 

In the laboratory, styrene can be prepared by the decarboxylation of cinnamic acid, as shown in Reaction 1, using dry distillation. However, styrene is produced commercially from ethylene and benzene, two basic ingiedienis of the petrochemical industry. With electrophilic addition of ethylene to benzene, a mixture of ethyl benzene and diethylbenzene is obtained as own in Reaction 2. The dehydrogenation of these benzene derivatives produces slyrene and divinylbenzene, respectively (Reaction 3). A detailed synthesis of styrene is described by Berthelot et al (6). As mentioned earlier, styrene is an important monomer in many industrial polymers. Additionally, divinylbenzene which is produced as a by-product is an effective crosslinker for ion-exchange resins, polystyrene-based supported reagents and catalysts, and low profile additive in a number of liquid molding resin systems. 

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