Vinylic Hydrogen Pka

Benzylic position allylic position propargylic position aryl aryl hydrogen.

Vinylic hydrogen pka.

The libretexts libraries are powered by mindtouch and are supported by the department of education open textbook pilot project the uc davis office of the provost the uc davis library the california state university affordable learning solutions program and merlot. A hydrogen atom bonded to an sp 2 carbon of an alkene. Water pka 15 7 9. Aryl 43 benzylic 41 15.

Alkane pka above 50. Alpha proton of ketone aldehyde pka 20 11. The vinylic hydrogens are shown in red. Alpha proton of ester pka 25 12.

Alpha h of ketones. World s strongest carbon acid. Dempsey eds ionization constants of organic acids in solution iupac chemical data series no. An allylic hydrogen is a hydrogen atom that is bonded to an allylic carbon in an organic molecule.

H2s hydrogen hs 9 00 h h h r c o c 4 11 h h 10 0 10 3 ro c o c h h h ro. Amide pka 18 10. Terminal alkyne pka 25 13. Amine pka 38 40 14.

The strength of a base is related to the pk a of its conjugate acid as pk b 14 pk a. Plain phenol has a pka 10 aliphatic nitro bicarbonate ethyl acetoacetate diethyl malonate water pka ion 2 4 pentandione sulfide carbonic acid carboxylic acids cyclopentadiene. None of the other hydrogens are vinylic. For strengths of organic acids see e.

Because of resonance stabilization of the conjugate base an α hydrogen in an aldehyde not shown in the picture above is far more acidic with a pk a near 17 compared to the acidity of a typical. Aldehydes feature an sp 2 hybridized planar carbon center that is connected by a double bond to oxygen and a single bond to hydrogen the c h bond is not ordinarily acidic. We also acknowledge previous national science foundation support under grant numbers 1246120 1525057 and 1413739. 23 pergamon press oxford uk 1979.