chemfan1 - 20-12-2010 at 16:54
I know how to name alkanes and branched alkanes, but how do I name alkanes that have branches on other branches. For example, let's say I have decane
in the straight chain isomer, then at the 5 carbon I have a propyl group and on the second carbon of the propyl group I have a methyl group. What do
I call this? Would it be 5-(2-methylpropane)-decane or 5-(2-methylpropyl)-decane?
I know -yl is the suffix for alkane branches, but what about alkene or alkyne branches. Let's say I have pentane and attached at the 2 carbon is an
ethene. What would this be called? 2-(ethene)-petane?
When a hydrocarbon has double and triple bonds what are they called? 1-butene-3-yne? but-1-ene-3-yne?
Which name is better accepted, 2-butene or but-2-ene (ignoring isomers).
Why are alkenes and alkynes more reactive than alkanes? Aren't double and triple bonds stronger? Is it because they are unsaturated and the
hydrogens in alkanes provide a kind of shielding that protects the single bonds?
psychokinetic - 20-12-2010 at 23:54
I'll start with the placement of the numbers: But-2-ene is apparently official, but both are accepted.
In terms of the branched chain, IUPAC says make the whole sidechain an -yl, but I very often see it. (i.e. I'm used to seeing your example as
5-(2-methylpropane)-decane. (Doesn't mwean it's 'right', though.
psychokinetic - 20-12-2010 at 23:57
Sorry, I forgot about the last bit.
Alkenes and alkynes are more reactive because they have those delicious extra electrons hanging out for electrophiles to attack. 
When it gets down to a single bond, there are enough electrons to make a bond and no extraneous ones.