Search results
Results from the WOW.Com Content Network
Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula C 2 H 4 or H 2 C=CH 2. It is a colourless, flammable gas with a faint "sweet and musky " odour when pure. [ 7 ] It is the simplest alkene (a hydrocarbon with carbon–carbon double bonds ).
In this reaction a variety of reagents add "across" the pi-bond(s). Chlorine, hydrogen chloride, water, and hydrogen are illustrative reagents. Polymerization is a form of addition. Alkenes and some alkynes also undergo polymerization by opening of the multiple bonds to produce polyethylene, polybutylene, and polystyrene.
In 1 H NMR spectroscopy, the hydrogen bonded to the carbon adjacent to double bonds will give a δ H of 4.5–6.5 ppm. The double bond will also deshield the hydrogen attached to the carbons adjacent to sp 2 carbons, and this generates δ H =1.6–2. ppm peaks. [14] Cis/trans isomers are distinguishable due to different J-coupling effect.
A hydroxyl group (OH −) attaches to one carbon of the double bond, and a proton (H +) adds to the other. The reaction is highly exothermic. In the first step, the alkene acts as a nucleophile and attacks the proton, following Markovnikov's rule. In the second step an H 2 O molecule bonds to the other, more highly substituted carbon.
An overall process of disproportionation can be observed, where "light", hydrogen-rich products are formed at the expense of heavier molecules which condense and are depleted of hydrogen. The actual reaction is known as homolytic fission and produces alkenes , which are the basis for the economically important production of polymers .
In the case of dicobalt octacarbonyl or Co 2 (CO) 8 as a catalyst, pentan-3-one can arise from ethene and CO, in the absence of hydrogen. A proposed intermediate is the ethylene-propionyl species [CH 3 C(O)Co(CO) 3 (ethene)] which undergoes a migratory insertion to form [CH 3 COCH 2 CH 2 Co(CO) 3]. The required hydrogen arises from the water ...
Generally, the choice of method is governed by the raw material and energy situations as well as by the availability of oxygen at a reasonable price. In general, 100 parts of ethene gives: 95 parts acetaldehyde; 1.9 parts chlorinated aldehydes; 1.1 parts unconverted ethene; 0.8 parts carbon dioxide; 0.7 parts acetic acid; 0.1 parts chloromethane
In the first step, borane (BH 3) adds to the double bond, transferring one of the hydrogen atoms to the carbon adjacent to the one that becomes bonded to the boron. This hydroboration is repeated two additional times, successively reacting each B–H bond so that three alkenes add to each BH 3. The resulting trialkylborane is treated with ...