abdullah1443
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It says that CH3CH2CH2Br undergoes addition polymerisation to form poly(propene), how is this??

Thank you.
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Adamburgess38
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That can't be correct, it should form poly(Bromopropene)?
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HateOCR
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It forms HBR and -(CH2CH2CH2)- so i don’t see how it can be an ADDITION polymer since there isnt meant to be a product
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Heartbeat3458
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CH3CH2CH2Br Is a haloalkane and it’s unusual for it to be able to undergo addition polymerisation.
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username2752874
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(Original post by abdullah1443)
It says that CH3CH2CH2Br undergoes addition polymerisation to form poly(propene), how is this??

Thank you.
Maybe with an elimination step in between with ethanolic sodium hydroxide, otherwise no.
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abdullah1443
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(Original post by Adamburgess38)
That can't be correct, it should form poly(Bromopropene)?
it might be misprint then, so if it were to be poly(Bromopropene) how will the formula be pls??
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abdullah1443
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(Original post by HateOCR)
It forms HBR and -(CH2CH2CH2)- so i don’t see how it can be an ADDITION polymer since there isnt meant to be a product
That makes most sense, probably an error. Thanks everyone!
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Adamburgess38
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(Original post by abdullah1443)
it might be misprint then, so if it were to be poly(Bromopropene) how will the formula be pls??
-(C-C)- then have a methyl group and Br on one C and Hs on the other two?
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username2752874
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(Original post by Adamburgess38)
-(C-C)- then have a methyl group and Br on one C and Hs on the other two?
How is that going to form from a molecule that's already saturated?

You'd have to do something like aelimination reaction, then use bromine and UV light, to get bromo alkene. Then you'd be able to polymerise
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Pigster
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(Original post by abdullah1443)
it might be misprint then, so if it were to be poly(Bromopropene) how will the formula be pls??
bromopropene doesn't exist (without stating when the Br is attached).

Assuming 1-bromoprop-1-ene, that'd be one heck of a misprint: CH3CH2CH2Br when it should have been CH3CHCHBr.

I think it was likely meant to be 1-bromopropane eliminated to propene followed by addition polymerisation forming poly(propene).

e changed to a - thank you charco.
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charco
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(Original post by Pigster)
bromopropene doesn't exist (without stating when the Br is attached).

Assuming 1-bromoprop-1-ene, that'd be one heck of a misprint: CH3CH2CH2Br when it should have been CH3CHCHBr.

I think it was likely meant to be 1-bromopropene eliminated to propene followed by addition polymerisation forming poly(propene).
Typo "1-bromopropane"

1-bromoprop-1-ene would technically be incorrect as propene sets the carbon chain number with the beginning of the double bond at C#1, making the alkenyl locant redundant.
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Pigster
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(Original post by charco)
1-bromoprop-1-ene would technically be incorrect as propene sets the carbon chain number with the beginning of the double bond at C#1, making the alkenyl locant redundant.
Am I mis-interpreting:

P-14.3.3 Omission of locants
The practice of omitting locants when there is no ambiguity is widespread. However for designating preferred IUPAC names it is necessary to be prescriptive about when omission of locants is permissible. Thus, in preferred IUPAC names, if any locants are essential for defining the structure, then all locants should be cited. For example, the omission of the locant ‘1’ in 2-chloroethanol, while permissible in general usage, is not allowed in the preferred IUPAC name 2-chloroethan-1-ol.

The position of the bromine needs stating, therefore by my reading, so would the position of the double bond.
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charco
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(Original post by Pigster)
Am I mis-interpreting:

P-14.3.3 Omission of locants
The practice of omitting locants when there is no ambiguity is widespread. However for designating preferred IUPAC names it is necessary to be prescriptive about when omission of locants is permissible. Thus, in preferred IUPAC names, if any locants are essential for defining the structure, then all locants should be cited. For example, the omission of the locant ‘1’ in 2-chloroethanol, while permissible in general usage, is not allowed in the preferred IUPAC name 2-chloroethan-1-ol.

The position of the bromine needs stating, therefore by my reading, so would the position of the double bond.
My understanding is the highlighted passage:

The position of the double bond is unequivocable, it has to be on C#1. This then requires only the position of the bromine to be located.

CH2=CBr-CH3 is 2-bromopropene
CH2=CH-CH2Br is 3-bromopropene

There is no ambiguity, hence the need for a locant on the alkenyl group is redundant.
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