2 - -ethane proton spectra

A very important characteristic of spin-spin splitting is that protons that have the same chemical shift do not split each other s signal Ethane for example shows only a single sharp peak m its NMR spectrum Even though there is a vicinal relationship between the protons of one methyl group and those of the other they do not split each other s signal because they are equivalent... 

The proton NMR spectrum shows chem shifts of 6.93 5.957- (Ref 1). Photolysis with a Hg arc lamp gives N, nitrous oxide, methane, and ethane (Ref 2). It was found to produce colon and rectal carcinomas in rats after oral administration at 12mg/kg weekly, induction period 235 days (Ref 3)... 

We have established that the formation of enols is catalysed by acids and bases. The reverse of this reaction—the formation of ketone, from enol—must therefore also be catalysed by the same acids and bases. If you prepare simple enols in the strict absence of acid or base they have a reasonable lifetime. A famous example is the preparation of the simplest enol, vinyl alcohol, by heating ethane-1,2-diol (glycol—antifreeze) to very high temperatures (900 °C) at low pressure. Water is lost and the enol of acetaldehyde is formed. It survives long enough for its proton NMR spectrum to be run, but gives acetaldehyde slowly. 

The ESR spectrum of ethane radical cation at 4 K in SFe contained a 1 2 1 triplet because of two strongly coupled protons (15.25 mT), corresponding to a spin-... 

For example, all the protons of ethane (CH3-CH3) are in identical electronic environments and are therefore equivalent. Hence there will be no spin-spin splitting of the protons the nmr spectrum will contain only singlets (signals with one peak). Furthermore, since all the protons in ethane are equivalent they will have identical chemical shifts, and will occur as one signal. Hence the nmr spectrum of ethane will have one singlet. An example where spin-spin splitting occurs is propane. The methylene protons are nonequivalent to the methyl protons. As a result, the six nonequivalent adjacent methyl protons will split the methylene proton s signal into a heptet (seven peak multiplet). 

NMR spectrum of the grafted 2-(2 -ethoxyethoxy)-ethane thiol on PVC is shown in Figure 9. It is worthwile mentioning that the further the protons are far from the backbone of the pol3rmer the higher is the resolution. This is due to the fact that the proton near the polymer chain are more restricted in rotation. 

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