Halogeno Flashcards
Why is methyl halogenoalkane favoured for sn1 reaction
Stability of carbonation formed
Less H more stable
Is sn1 first order or second order
First order; 2 separate steps, only rx for rate
Why benzene c6h5ch2cl primary halide still prefer sn1?
Resonance stability so benzyl carbonation by delocalisatuon of the positive charge into benzene ring
Naoh(aq)/koh(aq) heat vs alcoholic koh heat whats the difference for halogenoalkane
Aqueous subs oh but alcoholic eliminates to form alkene no oh no nothing
Alcohol to halogeno alkane
Hx gas heat (NaBr conc h2so4 heat) or pcl5
Cn halogenoalkane how to get ch2nh2
Lialh4 dry ether, h2 Ni catalyst high TandP, H2 pd or pt catalyst
Acidic hydrolysis of cn
H2so4 or hcl aq heat under reflux
Form amine from halogeno?
Excess nh3 in ethanol heat in sealed
BTW if halogenoalkane Excess the h on nh2 gets substituted eventually protonated
Why order of reactivity I>Br>Cl
Bond energy proportional to bond strength
Preparation of halogenoarenes
Cl2(g) anhydrous Alcl3
Why halogenoarenes less reactive for nucleo sub than haloalkane
Shorter stronger cx bon, Lone pair of halogen delocalised into benzene creating partial double bond character, pi electron cloud repels lone pair of nucleophile
Why halogenoalkene also unreactive for nucleophilic sub
Halogen delocalised to adjacent c=c partial double bond
Why is it call electrophilic addition even though halogens are nucleophile
Hx(g) H is the electrophile then halogen in nucleophile but c=c electron rich need electrophile that’s why called EA
Why adding agno3 (aq) to nucleo sub of ch3ch2cl naoh(aq) heat gets white ppt agcl
Cl- + Ag+ –> agcl(s)
Whats saytzeff rule?
When you eliminate to form an alkene, resulting major product should have lesser H on double c
