[George Pumpkin]

Hi everyone,

I am assigned to do a task in the lab and received a manual for it. Most of the procedures are clear but there is one bit I am very uncertain of. It tells me the following:

(x) Filter the hot solution through a fine filter paper.
(y) Wash the residue with HCl (1:40) and six times with hot water.
(z) combine the two filtrates in a 1000 mL beaker.

What confuses me is - I firstly assumed I will perform suction filtration with the Buchner flask + funnel and then wash the precipitate with some acid and then six times with hot water. But then it says I need to combine filtrates, hence I thought I need to use a separating funnel to perform 'washings'. I did a search on internet and indeed in most cases people advise to use separating funnel. However, to separate things - you need this solutions to be insoluble in each other (e.g. organic solution + aqueous solution). I read the manual couple of times ans can't find any organic reagents in it (in previous steps, HCl, Na2CO3 solutions were used). So I come back to an idea with using the Buchner flask and funnel and vacuum filtration.

Could someone please tell me their opinion whether I am on a right way with this procedure.

P.S. I just had a second thought - in step (x) the solution that is used contains some amount of Silica - does this going to make it to be insoluble in water/aqueous solutions and thus making possible separations?

I look forward to hearing from you 

[Dan]

No sep funnel here, washing a solid is normally done by filtration. A trituration really.

It sounds like your product is in the acidic and hot water fractions.

If you post the actual reaction you are doing, it will be easier to tell.

[Arkcon]

Read your protocol more critically -- as you've interpreted it, you're going to suction filter a solid, then scrape it out, and shake it in a separatory funnel?  Six or more times?  Why would you switch "funnel" types?  How would a sep funnel work for washing a solid?  And if it would, why wouldn't you use it at the start, except for the fact that ... it wouldn't work?