Your Question About Easy Weight Loss

Donna asks…

what are functions of sulfuric acid quenching reaction of ketone mixture?

In an experiment of making tertirary alcohol using grignard synthesis, magensium, isobutyl bromide and a ketone was used. in part of the experiment the unknown ketone was mixed with diethyl ether and stirred for several mintures and then finally quenched with sulfuric acid before added to the unknown bromide solution. why?

weight loss cardiff answers:

The usual purpose of adding acids or bases to a mixture is to alter the ph levels. If the constitutes of the acid does not enter into the reaction, then the ph level need to be changed to form the reaction with the bromide. Most likely forming a precipitate of ethylene bromide in alcohol.

Mary asks…

I need some help with chemistry ASAP please?

Calculate the mass (g) of the solute diethyl ether and the mass (kg) of the solvent chloroform that should be combined to prepare 9340 g of a solution that is 2.80 parts per hundred by mass diethyl ether.

weight loss cardiff answers:

2.80 = mass solute x 100/ 9340

mass solute = 261.5 g

mass water = 9340 – 261.5 = 9078.5 g => 9.0785 Kg

Mandy asks…

What would happen if petroleum ether was used instead of dry diethyl ether for grignard reaction?

The reaction being grignard reaction with the preparation of phenylmagnesium bromide from bromobenzene, dry ether and magnesium. Would the petroleum ether not produce the grignard reagent?
but why do they require diethyl ether? petroleum ether also has that O that can be used, does it not?

weight loss cardiff answers:

I thought this was already aswered.
Grignard reagents require a true ether solvent for their formation. Petroleum ether is a hydrocarbon.

There is no O in pet ether. It’s just a cut of pentane, with some cats and dogs left in it. It will not make a Grignard reagent.

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Your Question About Easy Weight Loss

Mark asks…

Other than THF and diethyl ether, what could one use as a solvent for a Grignard? Why are these suitable?

So THF and diethyl ether are both slightly polar but why is that important? I need to know other solvents that could be used for Grignard and what would make a bad solvent and why? I’m guessing a nonpolar solvent would make a bad solvent, or maybe something very polar and thus easier for water to dissolve in? Help!

weight loss cardiff answers:

You’re partly right, a nonpolar solvent wouldn’t work. The Grignard reagent is polar and would not be very soluble in a nonpolar solvent.

To see what kind of polar solvents work best, first remember that the Grignard reaction proceeds through an SN2 mechanism. Your Grignard reagent has a dipole moment, (δ−)R−(δ+)MgBr. That partial negative charge turns the R group from a bad nucleophile to a strong nucleophile, which SN2 needs. But it also makes it a strong base. Because of that, we have to be careful with our solvent. If the solvent we use is even a little bit acidic, some of the Grignard reagent will be diverted into an acid-base side reaction with the solvent, instead of the desired nucleophilic substitution.

So, to enhance a reagent’s nucleophilicity for SN2, we need to use a solvent that is polar, but cannot act as an acid. THF and Et2O fit this description; they have dipole moments but don’t contain acidic hydrogens. Since they won’t give up H+ (a proton), we call this type of solvent a “polar aprotic” solvent.

Grignard reagents in particular are highly reactive toward many polar aprotic solvents, further reducing the number of solvents that will work. For instance, your Grignard reagent would attack an acetone solvent, (CH3)2C=O, since it contains a ketone. You’re basically forced to use an ether solvent with Grignard. So, another ether solvent you might use for Grignard is dibutyl ether.

Short, cram night before the test version:
1) Grignard is SN2
2) polar aprotic solvents favor SN2
3) Grignard side-reacts with solvents other than ethers

Laura asks…

Is benzoic acid more soluble in water or diethyl ether?

When both water and diethyl ether were added to benzoic acid, which layer(ie the organic or aqueous layer) can the benzoic acid can be found.
i am also curious that if benzoic acid is more soluble in diethyl ether, is it due to the 6 carbon chain of the benzoic acid?
C6H5coo- soluble in water?

weight loss cardiff answers:

Benzoic acid is more soluble in diethyl ether than water.

So benzoic acid would be in the organic layer.

Bear in mind that ether is less dense than water, so the extract would be on top.

Benzoic acid is more soluble in ether because the benzene ring is nonpolar, aye.

Benzoate salts are water soluble, though, because water is better able to stabilize the negative charge on the oxygen.

Maria asks…

what is the difference Between Ethyl Ether and Diethyl Ether?

i was in chemistry the other day and we were talking about Ether
and i was curious what’s the difference between the two.

weight loss cardiff answers:

Nothing, they represent the same compound. Diethyl ether is the correct IUPAC name for the compound composed of an oxygen attached to two ethyl groups. Ethyl ether is a common name for the same compound. Not technically correct, but widely understood to mean diethyl ether.

Note that sometimes, this compound is also refered to simply as “ether”.

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