Optical Purity and enantiomeric excess?

Curt Broadhead: The R form must have an optical rotation [α] of -23.1° which comes from it being a mirror image of the S form (and the equal and opposite molar absorptivities of circularly polarized light but let's not go into that).1) Because the rotation is -ve there must be more of the R isomer as rotations are additive (see below).2) Without calculating 3 first: Optical purity (ee) =([α]obs/[α]max)×100%= -17.7/-23.1 = 76.6%3) As stated above the [α]s are additive. Let fraction of S be x, then fraction of R = 1-x+23.1x + -23.1(1-x) = -17.746.2x = -17.7+ 23.1x = 5.4/46.2 = 0.117 or 11.7% of the S form, 88.3% for the R.ee = (R - S)×100 = (0.883 - 0.117)×100 = 76.6% http://en.wikipedia.org/wiki/Enantiomeric_excess...Show more

Vernon Martorana: I'll be honest - i don't have an understanding of fully all the ins and outs (no pun intended) of the entire "purity" ring dealio. I will be able to say i know some teenage girls who wore a purity ring until they ha! ve been married and some that proceed to put on one. I under no circumstances heard someone consult with it as being ceremonially married to her father but as a substitute a bodily reminder of a dedication that feminine had made to preserve her virginity unless marriage. As for Christian women "submitting" to guys? HA! My spouse (and i'd accept as true with her) does not put up to me. Some zealous fundamental Christians point to a opt for few verses (taken out of context, if you could think that...) and declare that as why the man is "over" the lady. I disagree; man and woman are in partnership with one leading in some respects and the opposite leading in different respects. As for private empowerment; i'd say fully with the working out that God is finally in charge. I do know many Christian ladies which have talked candidly with their daughters about intercourse and told them it's a distinguished & attractive expression of affection between married persons; i know some Chr! istians think sexuality is whatever that must be repressed but! i'm satisfied that's not what God meant. Peace, bill...Show more