Lewis Reaction Questions (Organic Chemistry)

[cheechnchong]

[SOLVED] Lewis Reaction Questions (Organic Chemistry)

Homework Statement

1) H2C=O + CH3NH2 <-----> ?
2) CH3(C=O)-CH2(C=O)-OCH3 + CH3O(-) <-------> ?
3) CH3CH2CH2-COOH + Na2CO3 <------> ?

The Attempt at a Solution

1) My Answer: CH3NH2 is the lewis base and H2C=O is the lewis acid. Nitrogen donates to H2C=O, while double bond is broken. Both of them combine as CH2-O-CH3NH2.

2)My Answer: The CH3O is the lewis base and the "long set" is the lewis acid. The oxygen of the lewis base donates to the lewis acid, as the CH3 cleaves off the oxgen of the lewis base. The complete reaction is...(CH3)2O + CH3(C=O)CH2(C=O)O(-)

3) My Answer: I eliminated 2Na+. CO3(-) is the lewis base and the "long set" is the lewis acid. The carbon from lewis base donates to lewis acid, as the H cleaves off the Hydroxide in the lewis acid. The complete reaction is...CH3CH2CH2CH2-COO(-) + HCO3

I'd really like to get this material down. Thanks!

 

[chemisttree]

Homework Statement

1) H2C=O + CH3NH2 <-----> ?
2) CH3(C=O)-CH2(C=O)-OCH3 + CH3O(-) <-------> ?
3) CH3CH2CH2-COOH + Na2CO3 <------> ?

The Attempt at a Solution

1) My Answer: CH3NH2 is the lewis base and H2C=O is the lewis acid. Nitrogen donates to H2C=O, while double bond is broken. Both of them combine as [/bCH2-O-CH3NH2.

Not exactly... Look at the reaction to produce a schiff base. Which carbon on formaldehyde is the Lewis acid? As you have shown the attachment to oxygen, oxygen is acting as a Lewis base in this example... and the bond to methylamine is ambiguous.

2)My Answer: The CH3O is the lewis base and the "long set" is the lewis acid. The oxygen of the lewis base donates to the lewis acid, as the CH3 cleaves off the oxgen of the lewis base. The complete reaction is...(CH3)2O + CH3(C=O)CH2(C=O)O(-)

No. Which proton is acidic in methylacetoacetate ('long set')? Dimethyl ether will not be formed under these conditions. At best you will exchange out the methoxy group on the methylacetate functionality. The net reaction (which could occur) is a wash... one molecule of methoxide (-OCH3) is produced and one molecule of methylacetoacetate ('long set') is produced.

3) My Answer: I eliminated 2Na+. CO3(-) is the lewis base and the "long set" is the lewis acid. The carbon from lewis base donates to lewis acid, as the H cleaves off the Hydroxide in the lewis acid. The complete reaction is...CH3CH2CH2CH2-COO(-) + HCO3

I'd really like to get this material down. Thanks!

This last one looks good. And not a moment too soon. Butyric acid smells like baby vomit and the sodium salt is non-volatile (ie. no smell).