Question

In the acetylation of ferrocine, what is the purpose of a CaCl2 drying tube? What chemical reaction is it trying to prevent?

Lab procedure provided here on page 5: http://nicholschem22.weebly.com/uploads/1/2/4/9/12497207/ferrocene.pdf

Answer 1

if any moisture is there, it will be absorbed by the CaCl2 present in drying tube as the name indicates :)

Answer 2

bcoz moisture(H2O) wont make the reaction goo:)

Answer 3

so it dries the acetic anhydride and phosphoric acid?

Answer 4

and also, can you help with a mechanism for the chemical reaction it is preventing if possible?

Answer 5

i think it only get converts CaCl2 (anhydrous) -------> CaCl2.H2O (hydrous)
that's all
In most of reaction this CaCl2 is used its common practice in organic chemistry synthesis

Answer 6

oh and one more thing. in the procedure where it says use a water bath, i will be using a sand bath instead

Answer 7

where did the water come from?

Answer 8

It may be from ur reaction mixture due to impure reactant which might have absorbed the water and when u carry reaction them may evolve and another important is that moisture should not enter from outside to inside that is also possible right :) putting guard tube (drying tube ) guards the system from surrounding

Answer 9

hm. so do you think you can help with a mechanism for the reaction this drying tube is preventing?

Answer 10

CaCl2 (anhydrous) -------> CaCl2.H2O
this is the thing
cacl2 after absorbing moisture get converted into hydrous state :)

Answer 11

no i meant an arrow pushing mechanism sorry

Answer 12

and im still confused? so i add the drying tube to prevent water from forming?

Answer 13

http://orgchem.colorado.edu/Technique/Procedures/Drying/Drying.html

you want mechanism of reaction :) or the mechanism done by drying tube

Answer 14

the mechanism of what would happen if the drying tube was not there. since im asking what chemical reaction this drying tube is preventing from happening

Answer 15

nope it will not prevent water from forming
it will absorb excess unwanted moisture if present in the system or surrounding

Answer 16

so if there was excess unwanted moisture like water, which reagent would it be reacting with in this case? the ferrocene, acetic anhydride, or phosphoric acid?

Answer 17

OK Ok i got it now :)

Answer 18

?

Answer 19

it will with acetic anhydride , ferrocene is stable with air and mosture it will not be affected and though the phosphoric acid :)

Answer 20

so for my question i should draw the mechanism of water reacting with acetic anhydride?

Answer 21

to form acetic acid :) yup

Answer 22

thanks! may i ask one more question?

Answer 23

yes please :)

Answer 24

do you know how i could do the mechanism for this reaction? ferrocene reacting with acetic anhydride and phosphoric acid to form acetylferrocene

Answer 25

do u know why phosphoric acid is used here :)

Answer 26

i do not

Answer 27

what you know abt this reaction , then let me know

Answer 28

nothing really chem is really confusing

Answer 29

LOL :) first acetic anhydride reacts with phosphoric acid to form acyl group which then attacks the ferocene:) i have given hing=t now you do it

Answer 30

hmm

Answer 31

okay one more question!

Answer 32

regarding this friedels craft

Answer 33

yup;)

Answer 34

so i was able to do part A. but im not sure how to do part B

Answer 35

LOL u should learn basics of organic are u in college

Answer 36

yes

Answer 37

ive taken the 2 semesters a year ago and i am taking the lab now but i forgot a lot of it

Answer 38

LOL :)

Answer 39

so. is the top group the ketone and a ch2 group

Answer 40

bottom is everything except for the cl?

Answer 41

I too dont know LOL :)

Answer 42

wait let me try

Answer 43

k

Answer 44

NEVERMIND GOT IT THANKS

Answer 45

LOL what u got let me know i couyld not do the third step