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How do you guys memorise all the synthetic routes in ocr a level chemistry??? Please

Hi guys I'm really struggling to memorise all the synthetic routes, could you guys please give me any tips and tricks to help and also methods of applying it to exam questions.
I would really appreciate it. Thanks x.
Original post by LoneGiraffex
Hi guys I'm really struggling to memorise all the synthetic routes, could you guys please give me any tips and tricks to help and also methods of applying it to exam questions.
I would really appreciate it. Thanks x.
Use https://www.ocr.org.uk/images/359182-organic-synthesis-reaction-pathways.pdf to test your knowledge.
Remember them one by one, in the order of the textbook.

So start off with:
Alkane -> haloalkane. Radical substitution. UV light. Produce many products due to termination step. Has further propagation and substitutes at different point.

Alkene: electrophilic addition. To alkane (H2, 423K, Ni catalyst), alcohol (conc H3PO4 or H2SO4, reflux), to haloalkane. Forms major/minor product based on carbocation stability.

Alcohol. Partial oxidation by H2SO4, K2Cr2O7. Orange to green. Primary alcohol -> aldehyde (distillation) -> carboxylic acid under reflux. Secondary alcohol to ketone under reflux. Dehydration to alkene using conc H3PO4 or H2SO4. With NaX (halide) + H2SO4 under reflux to haloalkane. 2NaX + H2SO4 -> 2HX + Na2SO4. Make HX in situ under reflux, as it is toxic.

Haloalkane. Nucleophilic substitution. To alcohol by NaOH. [this concludes year 12 organic. make sure you have memorised all of year 12 before adding year 13 knowledge, as you would revisit ketones/aldehydes and haloalkanes. also learn the limitations. e.g radical substitution producing many side products]. You can see how alkanes, alkenes and alcohols all link to haloalkanes.

For exam questions, it is linking your knowledge. Circle the functional groups in the starting molecule. Circle the functional groups in the end molecule. E.g Although you cannot directly go from haloalkane to alkene, you can do haloalkane -> alcohol -> alkene.
(edited 1 month ago)
Original post by BankaiGintoki
Use https://www.ocr.org.uk/images/359182-organic-synthesis-reaction-pathways.pdf to test your knowledge.
Remember them one by one, in the order of the textbook.
So start off with:
Alkane -> haloalkane. Radical substitution. UV light. Produce many products due to termination step. Has further propagation and substitutes at different point.
Alkene: electrophilic addition. To alkane (H2, 423K, Ni catalyst), alcohol (conc H3PO4 or H2SO4, reflux), to haloalkane. Forms major/minor product based on carbocation stability.
Alcohol. Partial oxidation by H2SO4, K2Cr2O7. Orange to green. Primary alcohol -> aldehyde (distillation) -> carboxylic acid under reflux. Secondary alcohol to ketone under reflux. Dehydration to alkene using conc H3PO4 or H2SO4. With NaX (halide) + H2SO4 under reflux to haloalkane. 2NaX + H2SO4 -> 2HX + Na2SO4. Make HX in situ under reflux, as it is toxic.
Haloalkane. Nucleophilic substitution. To alcohol by NaOH. [this concludes year 12 organic. make sure you have memorised all of year 12 before adding year 13 knowledge, as you would revisit ketones/aldehydes and haloalkanes. also learn the limitations. e.g radical substitution producing many side products]. You can see how alkanes, alkenes and alcohols all link to haloalkanes.
For exam questions, it is linking your knowledge. Circle the functional groups in the starting molecule. Circle the functional groups in the end molecule. E.g Although you cannot directly go from haloalkane to alkene, you can do haloalkane -> alcohol -> alkene.

Thank you, so you just keep on testing yourself until you've memorised everything?
I've drawn it out and I'm using flashcards to memorise but j think I'm going to struggle when applying it to questions.
And also when the questions say 'another product was formed with a higher yield, what was the other product?' Idk it all gets confusing to me
Original post by LoneGiraffex
And also when the questions say 'another product was formed with a higher yield, what was the other product?' Idk it all gets confusing to me

Can you give me an example of that sort of question.
If that was about alkenes, then its about the major/minor product and carbocation stability.
(edited 1 month ago)

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