Question

reagent	Molecular Weight	Gram	mmol	equivalents	d	mL
hydroquinone	110			1.0	xxxx	xxx
acetic anhydride	102	1		3.1	1.08
phosphoric acid	98				1.85	0.05
THEORETICAL PRODUCT	XXXXXXXXXXX	XXXX	XXX	XXXXXXXX	xxxxx	XX
4-(acetyloxy) phenylacetate				xxxxxxxxxx	xxxx	xxxx
acetic acid				xxxxxxxxxx	1.049

Please show step by step solution. Thanks!

Answer 1

reagent	Molecular Weight	Gram	mmol	equivalents	d	mL
hydroquinone	110	0.347 g	3.1	1.0	xxxx	xxx
acetic anhydride	102	1	9.8	3.1	1.08	0.925
phosphoric acid	98	0.0925	0.9	0.29	1.85	0.05
THEORETICAL PRODUCT	XXXXXXXXXXX	XXXX	XXX	XXXXXXXX	xxxxx	XX
4-(acetyloxy) phenylacetate	194.18	0.616 g	3.1	xxxxxxxxxx	xxxx	xxxx
acetic acid	60	0.74 g	12.3	xxxxxxxxxx	1.049	0.77

answers filled table.

first we want to know hydroquinone wt and moles using aceticanhydride wt and molecular weight

as per above reaction equvalents 3.1 more  aceticanhydride compare to hydroquinone 1, so

if calculate same ratio

aceticanhydride weight/ molecular weight*1000, 1/102 *1000 =9.80

acetic anhydride moles =9.8 millimoles ,

when grams to mls convertion (mass divided by with density) = 1/1.08

=0.925 ml

so 9.80 three times more moles so 9.8/3.1 = 3.1

hydroquinone =3.1*110/100 (millimoles to moles)

wt =0.347 g

millimoles already know 3.1 millimoles.

phosphoric acid : when mls to grams convertion (mls multiply with density) = 0.05*1.85

0.0925 g

we know moles weight/molecular weight

=0.0925/98*1000

=0.9 millimoles

equvalents = phosphoricacid milli moles/hydroquinone millimoles (because considered hydroquinone as 1), all caluculations with respect to the hydroquinone

=0.9/3.1

=0.29 equivalents.

same as in product expected product 4-(acetyloxy) phenylacetate molecular weight 194.18

to hydroquinone actylation will takes place form as 4-(acetyloxy) phenylacetate,

0.347/110*194.18

=0.61 g

millimoles same as hydroquinone

=0.61/194.18*1000

=3.1 millimoles

actic acid form from excess of acetic anhydride , acetic acid molecular weight 60

this will give one mole aceticanhydride two moles of acetic acid.