1,2-dichloroethane, reactant

A fiowsheet for this part of the vinyl chloride process is shown in Fig. 10.5. The reactants, ethylene and chlorine, dissolve in circulating liquid dichloroethane and react in solution to form more dichloroethane. Temperature is maintained between 45 and 65°C, and a small amount of ferric chloride is present to catalyze the reaction. The reaction generates considerable heat. 

This problem is solved in the reactor shown in Fig. 10.6. Ethylene and chlorine are introduced into circulating liquid dichloroethane. They dissolve and react to form more dichloroethane. No boiling takes place in the zone where the reactants are introduced or in the zone of reaction. As shown in Fig. 10.6, the reactor has a U-leg in which dichloroethane circulates as a result of gas lift and thermosyphon effects. Ethylene and chlorine are introduced at the bottom of the up-leg, which is under sufficient hydrostatic head to prevent boiling. 

The reactants dissolve and immediately begin to react to form further dichloroethane. The reaction is essentially complete at a point only two-thirds up the rising leg. As the liquid continues to rise, boiling begins, and finally, the vapor-liquid mixture enters the disengagement drum. A very slight excess of ethylene ensures essentially 100 percent conversion of chlorine. 

Homogeneous reactions are those in which the reactants, products, and any catalysts used form one continuous phase (gaseous or liquid). Homogeneous gas phase reactors are almost always operated continuously, whereas liquid phase reactors may be batch or continuous. Tubular (pipeline) reactors arc normally used for homogeneous gas phase reactions (e.g., in the thermal cracking of petroleum of dichloroethane lo vinyl chloride). Both tubular and stirred tank reactors are used for homogeneous liquid phase reactions. 

The most characteristic chemical reaction of an alkene is an addition reaction, in which atoms supplied by the reactant form o-bonds to the two atoms originally joined by the double bond (Fig. 18.9). In the process, the 7r-bond is lost. An example is halogenation, the addition of two halogen atoms at a double bond, as in the formation of 1,2-dichloroethane ... 

An improved synthesis of 3,4-dihydro-2,l-benzothiazine 2,2-dioxide was reported by Togo and co-workers using photochemical conditions . Treatment of A-alkyl 2-(aryl)ethanesulfonamides 18 with (diacetoxyiodo)arenes under irradiation with a tungsten lamp at 20-30 °C afforded 2,1-benzothiazines 19 and 20. Chemical yields and selectivities were dependent upon the choice of solvents and the reactant s substituents 18 (Table 1). When THF and EtOH were used as solvents, the reactions failed to give the cyclized products, since their a-hydrogen was abstracted by the intermediate sulfonamidyl radical. Compound 20 was obtained as a major product when 1,2-dichloroethane was employed as a solvent. In contrast, in the case of EtOAc as solvent, compound 19 was obtained as the major product. 

In a dry 3-1. three-necked round-bottomed flask, equipped u il.h a sealed mechanical stirrer (all-glass or glass-Teflon), a l ( llux condenser fitted with a calcium chloride drying tube and a 100-ml. dropping funnel, are placed 50.0 g. (0.500 mole) of (inely powdered succinic anhydride (Note 2), 133.4 g. (1.00 mole) of freshly crushed anhydrous aluminum chloride (Note 3), and 500 ml. of anhydrous 1,2-dichloroethane. The mixture is Hl.irred vigorously at room temperature for about 2 hours to dissolve as much as possible of the solid reactants. Then 50.0 g. (0.500 mole) of isopropimyl a< [Pg.81]

In-situ IR-spectroscopic characterization of the Friedel-Crafts acylation of benzene in ionic liquids derived from AICI3 and FeCl3 showed that the mechanism of the reaction in ionic liquids was the same as that in 1,2-dichloroethane (128). The immobilization of ferric chloride-containing ionic liquid onto solid supports (e.g., silica and carbon) however failed to catalyze the acylation reaction, because leaching was a serious problem. When the reaction was carried out with gas-phase reactants, catalyst deactivation was observed. 

The bromination of dibenzoazepine 63 in 1,2-dichloroethane gives the /raw.v-dibromide 64 as the only product. The reaction was monitored spectrophotometrically and found to exhibit a third-order kinetics (second-order in Br2). A significant conductivity has also been found during the course of bromination. Both spectrophotometric and conductometric measurements are consistent with the presence of Br3- salt intermediates at a maximum concentration of ca 2% of that of the initial reactants. The X-ray structure of dibromide 64 shows a considerable strain at carbons bearing bromine atoms. The strain appears to be responsible for an easy, spontaneous debromination of 64, as well as for high barrier for the formation of 64 from the bromonium-tribromide intermediate. That makes possible the cumulation of the intermediate itself during the bromination of 63119. 

The shift from air-based, once-through processes to oxygen-based recycle processes, and the corresponding change from reactant-lean to oxidant-lean processes. This not only considerably reduces the emissions and makes purge streams more concentrated and hence more easily combusted but also may lead to improved selectivity and productivity. Examples are the oxychlorination of ethylene to 1,2-dichloroethane and the epoxidation of ethylene. 

By using cyclic voltammetry, Schiffrin and coworkers [26, 186, 187, 189] studied electron transfer across the water-1,2-dichloroethane interface between the redox couple FefCNls /Fe(CN)6 in water, and lutetium(III) [186] and tin(IV) [26, 187] diphthalocyanines and bis(pyridine)-me50-tetraphenylporphyrinato-iron(II) or ru-thenium(III) [189] in the organic solvent. An essential advantage of these systems is that none of the reactants or products can cross the interface and interfere with the electron transfer reaction, which could be clearly demonstrated. Owing to a much higher concentration of the aqueous redox couple, the pseudo-first order electron transfer reactions could be analyzed with the help of the Nicholson-Shain theory. However, though they have all appeared to be quasireversible, kinetic analysis was restricted to an evaluation of the apparent standard rate constant o. which was found to be of the order of 10 cm s [186, 189]. Marcus [199] has derived a relationship between the pseudo-first-order rate constant for the reaction (8) and the rate... 

Neutral solvents The term neutral solvent applies here to solvents not predominately either acidic (protogenic) or basic (protophilic) in character. Some are weakly basic but not appreciably acidic (ethers, dioxane, acetone, acetonitrile, esters), some aprotic (benzene, carbon tetrachloride, 1,2-dichloroethane), and some amphiprotic solvents (ethanol, methanol). Aprotic solvents are used mainly in mixed solvents to alter the solubility characteristics of the reactants. 

The main by-products are acetaldehyde, formed from traces of water present in the reactants, and U-dichloroethane, obtained by tb reaction of hydrochloric acid with vinyl chloride, according to the following reaction ... 

After drying and reduction, the Pd-Ag/C catalysts are composed of bimetallic Eilloy nanoparticles ( 3 nm). CO chemisorption coupled to TEM and XRD analysis showed that that, for catalysts 1.5% wt. in each metal, the bulk composition of the alloy is close to 50% in each metal, whereas the surface is 90% in Ag and 10% in Pd [9]. Mass transfer limitations can be detected by testing the same catalyst with various pellet sizes [18]. Indeed, if the reactants diffusion is slow due to small pore sizes, the longer the distance between the pellet surface and the metal particle, the larger the influence of the difiusion rate on the apparent reaction rate. Pd-Ag catalysts with various pellet sizes were thus tested in hydrodechlorination of 1,2-dichloroethane. Results were compared to those obtained with a Pd-Ag/activated charcoal catalyst. Fig. 4 shows the evolution of the effectiveness factor of the catalysts, i.e. the ratio between the apparent reaction rate and the intrinsic reaction rate, as a function of the pellet size. The intrinsic reaction rate was considered equal to the reaction rate obtained with the smallest pellet size. When rf = 1, no diffusional limitations occur, and the catalyst works in chemical regime. When j < 1, the observed reaction rate is lower than the intrinsic reaction rate due to a slow diffusion of the reactants and products and the catalyst works in diffusional regime [18]. 

The catalytic activity in DHC reactions is usually measured by passing the reactant in an N2 stream over the catalyst and then through water or NaOH solution and determination of the adsorbed HCl. In the author s and other laboratories the increase in electrical conductivity was measured. The rate of HCl production decreased in the reaction of l- -butyl chloride at 603 K in the first 2 hours, but became nearly constant for several hours thereafter, and comparison of the activities after different pretreatments of a carbon could be performed when the linear increase of conductivity with time was established [143]. A few results are shown in Table 7.9. The catalytic activity of activated carbons and carbon black also increased in this case after heat treatment under nitrogen, and became quite high after treatment with ammonia at 1173 K. The activity at 603 K increased in the order l- -butyl chloride < 1-n-hexyl chloride < 1-isobutyl chloride < 1,2-dichloroethane. The surface area of the porous carbons had decreased drastically after the reaction. 

None of the chlorophosphetane is produced in the absence of the AICI3, and the amount of the latter employed has a marked influence on the product yield thus if the ratio of the three reactants alkene, PCI3 and AICI3 was 1 1 0.75 the yield was about 50%, the yield was about 80% if the ratio was 1 1 1 and > 95% if it was 1 1 1.25. Replacement of the dichloromethane solvent by either a pure aliphatic or aromatic hydrocarbon prevented phosphetane formation, and the use of 1,2-dichloroethane gave some phosphetane together with some dimerized alkene. 

Design a synthesis of 1,1-dichloroethane from each of the following. Write a series of equations, showing reactants and products, as illustrated in the Sample Solution. 

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