Plz explain this retro duels alder reaction 4 double bods double bon 2 and c3 or butadiene should have some single bo

4 double bods double bon 2 and C3 or butadiene should have some single bond character and CC; single bond should have some don slightly longer (140 pm) as compared to the typical carbon-carbon double bond length of 13 carbon single bond length of 154 pm in ethane. 2.6. METHODS OF FORMATION OF DIENES Due to the contributions of structures (II and II), it is expected that C utadiene are 134 pm in ethylene the typical catbon character. This has indeed been found to be so. The CC, and C C double bonds of butadiene pm in ethvie Similarly, C2-C3 single bond of butadiene is slightly shorter (146 pm) as compared to the typical cahe Dienes are generally prepared by a suitable modification of the methods used for making alkenes. Some 1. Pyrolysis of cycloalkenes (retro-Diels-Alder reaction). 1, 3-Butadiene is prepared by pasing 19q of these methods are discussed below: vapours of cyclohexene over heated nichrome (Ni-Cr-Fe) alloy. CH2 HC = CH2 CH HC HC CH A Nichrome (retro-Diels Alder reaction) CH CH2 Ethylene CH CH2 CH2 1,3 Butadiene Cyclohexene