Question

Based on the data table below, identify a general trend in reaction speed for ketones/aldehydes and provide an explanation for these trends.

Ketone	MM (g/mol)	Aldehyde	MM (g/mol)	Rxn time (min)	Product (g)	Theoretical	Yield
acetone	58.1	benzaldehyde	106.1	1.75	0.742	0.5406	137%
cyclopentanone	84.1	benzaldehyde	106.1	0	0.557	0.5926	94%
cyclopentanone	84.1	benzaldehyde	106.1	0	0.724	0.5926	122%
acetone	58.1	cinnamaldehyde	132.2	4	0.432	0.645	67%
cyclopentanone	84.1	4-methylbenzaldehyde	120.2	0	0.637	0.649	98%
acetone	58.1	4-methoxybenzaldehyde	136.2	18	0.618	0.661	93%
cyclopentanone	84.1	4-methoxybenzaldehyde	136.2	0	0.5	0.713	70%
cyclopentanone	84.1	4-methoxybenzaldehyde	136.2	0.5	1.385	0.713	194%

Answer 1

The trend for acetone:

acetone 58.1 benzaldehyde 106.1 1.75 0.742 0.5406 137%

acetone 58.1 cinnamaldehyde 132.2 4 0.432 0.645 67%

acetone 58.1 4-methoxybenzaldehyde 136.2 18 0.618 0.661 93%

As you can see with increase in methyl groups attached to the benzaldehyde, the % yield is decreasing

Reason:

the methyl groups are attached to benzaldehyde, the longer the chain the yield of the corresponding product decreases as it is difficult to break the longer methyl chains.

Similarly,

In the first 2 reactions for the same concentrations of cyclopentanone and benzaldehyde, the yield is different ... this may be because of the change in reaction conditions like temperature, reagent etc.

the reactions cyclopentanone and 4-methoxybenzaldehyde, for 0 rxn time the yield is greater for the less conc of 4-methoxybenzaldehyde .

with increase in conc of 4-methoxybenzaldehyde the rxn time increases and the yield also increases almost doubles