aommaster Posted January 1, 2004 Posted January 1, 2004 Ok. I was looking up something about cycloalkanes when this question popped up : Is it possible to have CycloalkEnes? So i looked it up, and there was something about trans- and cis- , can u please explain this to me, i read about it but i couldn't understand it! ok. One more, this substance looks EXTREMELY familiar, what is it? I know it looks deformed! But i'm not picasso. I drew it myself, using my own powerpoint presentation!
fafalone Posted January 2, 2004 Posted January 2, 2004 That's just a benzene ring. cis- and trans- refer to the orientation of substituents Picture a ethene (C=C) molecule with a substituent attached on the hydrogen that is drawn highest, now picture another substituent on the other C.. if it's also on top, it's cis ethene, if its on the bottom, its trans-ethene
aommaster Posted January 2, 2004 Author Posted January 2, 2004 I'm sorry to annoy you, but, i really don't understand . What is a substituent
YT2095 Posted January 2, 2004 Posted January 2, 2004 taken from the word "Substitute" it mean a Hydrogen could be replaced with something else or moved. a bit like replacing an ordinary H on a benzene ring with an OH to make Phenol. at least that`s the way I understand the post
wolfson Posted January 3, 2004 Posted January 3, 2004 Cycloalkanes have all single bonds, cycloalkenes have one or more double bonds and cycloalkynes have one or more triple bonds. (The picture you drew was a aromatic ring). Some examples are cyclopropene, cyclobutene, cyclopentene and cyclohexene, these all have different shapes, cyclohexene is the one with a aromtaic ring (benzene ring). Only the cis-alkene is is possible in cyclic structures with 5 or fewer carbons, trans Cycloheptene has been prepared and exists for a short time before converting to the stable cis-cycloheptene. Cycloalkenes of ring size greater than 7 can exist in both the cis and transforms. Cycloalkenes have the general formula C n H 2n-2.
aommaster Posted January 3, 2004 Author Posted January 3, 2004 What do u mean by, that it only exists for a short time? Does it collaps? And what is the difference between Cis-cyclo-something and a normal cyclo-something and a trans-cyclo-something
aommaster Posted January 3, 2004 Author Posted January 3, 2004 And correction, Cycloalkenes only have ONE double bond. then comes cyclodienes for two etc. You get the point, the same prefixes and suffixes By the way, in esterification, which part is the ethanoate part and which is the ethyl part? I've circled the part which i think is the ethanoate part, am i right?
YT2095 Posted January 3, 2004 Posted January 3, 2004 you are correct the bit you boxed is the Ethanoate part, the other is the Ethyl C2H5
wolfson Posted January 3, 2004 Posted January 3, 2004 Cycloalkenes can, of course, contain more than one double bond. If there are two bonds then the ene ending of the name is replaced with diene. If there are three bonds then the ene ending of the name is replaced with triene. For more double bonds, the Greek prefix is placed in front of the ene ending to indicate the number of double bonds.
aommaster Posted January 4, 2004 Author Posted January 4, 2004 Thanx YT. See? I'm learning something. For the first time i got it right! Thanx wolfson for your reply. I now understand all the suffixes. So, if a substance has let's say 5 double bonds, it would be called something diene 5?
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