Origins of halons and CFCs (1 Viewer)

[loser]

Do we have to know the origins of other haloalkanes as well?

What about ions like Br, C, F?

 

[mon_mon]

No. Only CFC's. Ion's like Br, Cl and F come FROM these CFC's. Although it wouldn't hurt to know about the production and uses of Haloakanes, in specific, CFC's.

 

[Constip8edSkunk]

Br comes from Halons

 

[mon_mon]

AS does Flurine and Chlorine. at least in the scope of that question.

 

[Constip8edSkunk]

what i meant was u cant get Br from CFCs, also F has zero ozone depletion potential

 

[mon_mon]

Right, i got ya. true. Chlorine is the only Halide you have to worry about in terms of Ozone depletion

 

[phenol]

haloalkanes usually synthesised from alcohols (Sn2 reactions) or alkenes

the halogen used come from electrolysis of brine

 

[toknblackguy]

wtf?
what's a haloalkane...and the heck are all you guys on about?!?

 

[phenol]

some alkane with a halogen in it (halogen = group VII on periodic table)

 

[toknblackguy]

oh man
i think i'm just gonna take things a bit easy
this is getting too complex for me...why do we have to know thoe damn equations?

 

[Constip8edSkunk]

those damn eqn?

which ones? the decomposition of ozone by cl yes, since dot pt requires it, ozones absorption of UV rays may also b helpful in describing their role in the stratosphere.

 

[toknblackguy]

no not those ones
i mean like hydrobromination, and umm..chlorination to form chloroethene, and the rest of em

 

[Constip8edSkunk]

hydrohalogenation and halogenation forms haloalkanes eg. chloroethane and 1,2-dichloroethane by reacting ethene w/ HCl or Cl2, and it breaks the double bond in addition reaction. you cant get Chloroethene that way, dunno how you produce chloroethenes tho... we dun get taught in the HSC anyway...

edit: those eqn are relatively easy to remember

H2C=CH2 + X-Y --> H2XC-CYH2

where the C atome has single bonds with 2 H atoms, the other carbon atom and either the X or Y atom

 

[toknblackguy]

chloroethene, from memory requires a Ni catalyst, and it forms choloroethene and hcl
C2H4 +Cl2 --> C2H3Cl + HCl

 

[mon_mon]

but we dont need to know those do we?

 

[toknblackguy]

hopefully not!
but just read over em...cause then in the exam, if they specify the reactants, we should be able to pull it outta the back of our heads..and get lucky

 

[mon_mon]

hmm...good advice. i'll take you up on that.

 

[+:: $i[Q]u3 ::+]

no

 

[mercury]

Halons are bromofluorocarbons used to extinguish fires in electrical and computer systems.
The main uses for CFCs were for refrigerants in refrigerators and air conditioners and as a propellant for aerosol cans.

js know how they kill the ozone in stratosphere and the montreal protocol. they wouldn't ask anything too complicated.

 

[loser]

So the only source of halons is fire extinguishers? Anything else? I guess thats probably enough though.