How To Set Up Vacuum Filtration

Filtration

Filtration is a technique used either to remove solid impurities from an organic solution or to isolate an organic solid. The two types of filtration commonly used in organic chemical science laboratories are gravity filtration and vacuum or suction filtration.

Gravity Filtration

Gravity filtration is the method of pick to remove solid impurities from an organic liquid. The impurity tin be a drying agent or an undesired side production or leftover reactant. Gravity filtration can be used to collect solid product, although more often than not vacuum filtration is used for this purpose because it is faster.

A filtration procedure called "hot gravity filtration" is used to separate insoluble impurities from a hot solution. Hot filtrations crave fluted filter paper and careful attention to the procedure to keep the apparatus warm only covered so that solvent does not evaporate. Hot gravity filtrations are no longer included in the routine procedures for the experiments in the organic chemistry education labs. If you need to exercise such a filtration, read the process in the Handbook and consult your TA.

To perform a standard gravity filtration, commencement select the size of filter paper that, when folded, will be a few millimeters beneath the rim of your stemmed funnel. Fold the paper into a cone by first folding it in half, and then in half again, as shown.

Next, back up the glass funnel in a ring or place information technology in the cervix of an Erlenmeyer flask. Wet the filter newspaper with a few milliliters of the solvent to be used in the following procedure. Wetting the paper holds it in place against the glass funnel. Cascade the mixture to be filtered through the funnel, in portions if necessary.

Fluted filter paper is often meliorate for gravity filtration with organic solvents. A diagram of how to fold fluted filter paper is shown below.

Vacuum Filtration

Vacuum filtration is used primarily to collect a desired solid, for instance, the collection of crystals in a recrystallization procedure. Vacuum filtration uses a Buchner funnel and a side-arm flask. Vacuum filtration is faster than gravity filtration, considering the solvent or solution and air is forced through the filter paper past the application of reduced pressure. Do not use vacuum filtration to filter a solid from a liquid if it is the liquid that you desire, and if the liquid is low humid. Whatever solvent which boils at almost 125 degrees or lower will boil off nether the reduced pressure level in the vacuum flask.

	To perform a vacuum filtration, clench the flask securely to a ring stand up.
	Add a Buchner funnel with a safe funnel adaptor.
	Obtain a piece of filter newspaper in the funnel that is minor plenty to remain apartment but big enough to cover all of the holes in the filter. If necessary, you can cutting a larger piece of filter newspaper down to size.
	Place the newspaper in the funnel.
	Connect the side arm flask to a vacuum source. Always use thick-walled tubing, since Tygon tubing will collapse nether reduced pressure level.
	Moisture the paper with a small amount of the solvent to be used in the filtration. This causes the newspaper to adhere to the plate and keeps materials from passing nether the paper during filtration. Turn on the vacuum source. Brand sure that the paper is secure on the filter, that air is existence fatigued through the paper, and that all of your appliance is securely clamped. If y'all are using a Neoprene filter adaptor, you might need to press on the funnel to engage the seal and thus the vacuum.
	Pour the mixture to be filtered onto the filter paper. The vacuum should rapidly pull the liquid through the funnel. Watch that particulates do not creep under the edges of the paper. If this happens, start over and advisedly pour portions of the solution onto the very center of the newspaper.
	Rinse the cake with a pocket-size amount of fresh, cold solvent to assist remove impurities that were dissolved in the filtrate.
	Advisedly disconnect the rubber tubing.
	Remove the filter paper and the collected solid that is on information technology.
	Usually you will need to prepare the product on a spotter drinking glass and let it air dry for a while.