[Jekel0000]

I am trying the determine what the reaction mechanism is of two salts + water + ether ether. The first salt is p-dimethoxybenzene (also called hydroquinone dimethyl ether) and is non-polar...The other salt is benzoic acid and is polar...The technique we are using is called extrapolation or to extrapolate the two salts using HCl acid and .5 Molar NaOH,

the procedure for separating a neutral ether, p-dimethoxybenzene (also called hydroquinone dimethyl ether), from an acidic compound, benzoic acid. Two types of drying agents and two different but common extraction solvents will be used for the purpose of gaining experience with the relative advantages and disadvantages of each. Therefore I have neglected the drying agent...

All I want to do is find a way of determining the Reaction Mechanism for this Experiment and I do not understand which reaction the reactants are having (Substitution, Addition, Elimination, or Rearrangement)

The procedure for the experiment is...
Weigh out approximately one gram of the dimethoxybenzene/benzoic acid mixture into a small Erlenmeyer flask. Obtain about 45 mL of diethyl ether (usually referred to as just ether), and cool the ether in an ice bath for a few minutes. Use a small amount of the cooled ether to dissolve the mixture, and transfer the resulting solution to a separatory funnel. Continue rinsing the small Erlenmeyer flask using the rest of the cooled ether, combining all of the ether rinses in the separatory funnel. Add about 10 mL of cooled 0.5 N sodium hydroxide solution to the separatory funnel, and shake the mixture in the proper manner. The Benzoic acid will react with the base and form the water-soluble benzoate anion (C6H5COO-).

Draw off the aqueous phase (on the bottom because water is denser than ether) into a 125 mL Erlenmeyer flask, and add a second, fresh 10 mL portion of chilled sodium hydroxide solution to the ether solution in the separatory funnel. Shake again to remove any traces of benzoic acid which might remain in the ether. Shake well as before, draw off the aqueous phase, and combine it with the first portion. This is called successive extraction and when performing such, you should always combine the like fractions.

I am trying to determine the first phase of the process, but I have only learned from General Chemistry what the substitution reaction is. I do not know how to determine what the reaction mechanisms are...what is it that determines how the reactants will process?

[discodermolide]

Firstly the technique is extraction not extrapolation. Neither of the compounds is a salt.

Secondly you are separating a non-polar compound (p-dimethoxybenzene) from a polar one (benzoic acid) by making a salt of one of them, doing the extraction (separation) and re-generating the original compound from which the salt was made.

So tell me now what is going on here.

[Jekel0000]

Extraction is a separation of a substance from one phase to another phase. In the experiment, the two solids are mixed together then diluted with Diethyl Ether to separate the two miscible compounds (Polar) benzoic acid (BA) and (non-Polar) p-Dimethoxybenzene(DMB) with (Polar) Diethyl Ether. Into two pure substances of BA and DMB. The BA is phased using an Acid and non-ionized water [H3O+][HO-] = 7 pH the extracted 3 times, dried with a drying agent(MgSO4). The DMB is phased using a base NaOH 2 times. Then dried using Na2SO4. Both Solutions are placed in separate containers then placed in the Evaporator…They will be weighted and a melting point will be observed....

Is there a mechanism of the reaction with ether phase in the chemical process?

[discodermolide]

No it is an extraction with diethyl ether. All you are doing is separating two compounds based on the chemical reactivity of one of them
Why do you think you treat the DMB /ether phase with NaOH?
 

[Jekel0000]

I'm guessing because it is water soluble...

[discodermolide]

Have another guess.

[Jekel0000]

water insoluble?

[discodermolide]

what other component could be in this solvent system that is removed by treatment with NaOH?