Quiz for the chemists!

[Th Entity]

Hey!

300ml water, pH 2 (glacial acetic acid) kept at 70C for 12H - can water evap (a little) so its amount reduces therefore affecting the pH by dropping it down further? (acetic would stay in solution because its boiling point is 117-119C water boils at 100C but i guess water could evap a bit at 70C (with stirring every once in a while for 12H) How much water you think could evap, and if then how that will affect the pH of the solution?


300ml water pH 2-3 (glacial acetic acid) diluted with 200ml water = 500ml water with a pH of? (chemists help) I know someone here can do the calculations :lol: I cant! BUT I TRIEEED

P.S. - 1st question is strange and i kinda understand it cant be answered with 100% certainty but i would appreciate guesses.

Lllove and Peace! :thumb_up:

 

[benzyme]

pH 2 - 3 is vague, because pH is a logarithmic function. To accurately determine [H+], a more precise value is needed.

 

[Th Entity]

benzyme i've been waiting exactly for you the pH is exactly 2.5

 

[benzyme]

C1V1 = C2V2
where C1V1 = 0.0032M * 0.3L = C2* 0.5L
pH of V2 = 2.72

pH/pOH Conversion

 

[Th Entity]

Man you are so smart! Thank you :d

Edit: Benz i think i accidentally confused you or im confused.
We are talking about this right:

300ml water pH 2-3 (glacial acetic acid) diluted with 200ml water = 500ml water with a pH of? (chemists help)

I meant to say 300ml water acidifed with acetic acid to pH of 2,5 and then diluted with 200ml plain water to 500ml what is the pH now?

300ml water acidified with few drops acetic acid to pH of 2,5 and to this acidified water we add 200ml plain water so the total amount of water will be 500ml thefore diluting further the acetic acid that is in the water, so wouldnt the pH rise(go towards neutral) instead of drop(further to acidity? How can the pH of acidic solution drop after dilution, sorry if i confused you or if im still confused.

 

[benzyme]

I think you’re a bit confused.
by the calculation, the pH did rise, albeit not by much.

 

[Mindlusion]

Yes the pH did rise, a negligible increase in mostly any organic chemistry application.

pH can decrease on concentration, too. Because pH/pKa is described as in a solution of water. For instance, glacial acetic acid, if used pure as a solvent, is not very acidic. Acetate is a strong enough base and most of the O-H protons stay attached. It's only when diluted with water and you create the new hydrogen bonding interactions that makes acetic acid acidic in water.

 

[Th Entity]

Wow that is fascinating i didnt know that, seems logical thank you benzyme and Mindlusion.
Do you have any guesses about the first question?

 

[benzyme]

that one I have been stewing over..
Some acids are azeotropic, so you can only evaporate so much before the pH levels off. I'm not sure if acetic acid is one of those acids. I know hydrochloric acid is, so is phosphoric.

this is one of those things you'd need to determine experimentally; the data for constants may be available in the CRC Handbook of Physics and Chemistry.

 

[Th Entity]

benz
so theoretically little evaporation of water is no problem but X amount of evaporated water can/will affect the pH but how? pH+/pH- ? (before i would guess, it would go towards acidity(pH-) (beacuse of water evap and acetic acid concetrating in solution BUT now, i wont even guess because my existing knowledge of pH was broken into pieces by you and Mindlusion :lol: :d respect!

Could you guess what that X amount of water could be and how the pH could change?

 

[benzyme]

apparently, acetic acid and water do not form an azeotrope.
theoretically, boiling of excess water will lower the pH.

using the C1V1 = C2V2 equation, and the link, the concentration of the final volume can be calculated into a final pH.
Wolfram-Alpha is also a good resource for reagent prep.

 

[Th Entity]

Thank you for all the help benz i really appreciate it :d

 

[benzyme]

anytime

 

[Th Entity]

CTM wrote:

When a protein molecule is heated in either acid or base, it is broken apart into its constituent amino acids. These amino acids will each carry a -1 charge in a basic solution. More charged molecules = more ionic strength. This is what we are looking for in our aqueous layer, very high ionic strength. I suggest that before any pulls are done on the solutions that they be heated either during the acid cook for A/B teks and after basifying and salting the mixture. If you let the solution react under warm conditions for several hours or even as long as 12 hours this would allow for more complete reaction. the proteins will slowly be torn apart. This could have a more drastic effect than the salt itself if there is enough protein in the mix.

Proteolysis/Non-enzymatic proteolysis section
- Acid Hydrolysis of proteins with strong mineral acids and prolonged high heat (or very high heat alone) The standard way to hydrolyze a protein or peptide into its constituent amino acids for analysis is to heat it to 105 °C for around 24 hours in 6M hydrochloric acid


Is CTM right? Does the breaking down of plant (MH/AC) proteins have bigger effect on yield than adding saline solution? And if this is the case, is it practical to do so? and how?
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I thought to do this: 300ml filtered water + MHRB in beaker acidified with acetic acid to pH of 2,5
then kept at 70C for 12h with magnetic stirring. Will this process hydrolise the MH plant proteins to amino acids so this increases the ionic strenght even further (+ adding saline solution after) so the AQ solution becomes very unfriendly to the nonpolars (DMT) upon basification which theoritically means bigger yield?
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If CTM is right and this indeed have big effect on yield is it practical do so?
I wont boil at 105 °C mixture of water and HCL for 24H for sure but will the plant proteins hydrolyse into amino acids if:

Instead of mineral acids - acetic acid
Instead of 105 °C - 70 °C
Instead of 24H - 12H

P.S - i was just curious because i saw this and it doesn't take much effort to apply it practically so i guess it wont hurt to do so if it works actually.

- i post it here because i don't want to make another thread

 

[Th Entity]

Any thoughts on reply #14?

and another question: 300ml water acidifed with acetic acid to pH of 2,5 and then added 200ml saturated NaCL water solution instead of plain water to 500ml total, does the pH change? (I know NaCL dont chnage the pH but i heard somewhere it changes the activity of something in solution that can change the pH or)?

since we already know that diluting 300ml acidified with acetic acid to pH 2,5 water with 200ml PLAIN water will put pH to 2,72 what if instead of plain water its used NaCL water is the pH change going to be the same?

 

[benzyme]

alkaline hydrolysis to proteins will do the same, it doesn't have to be done in acidic phase. the only difference is the terminal amine moiety of each amino acid will have a neutral charge, making the overall charge negative...won't migrate into nonpolars. the single greatest factor of maximum yield is cell lysis. STB does a good job of achieving this.

if you take the pH high enough, you won't even need to add salt. the addition of salt was intended to aid in preventing emulsions, and facilitating migration of the alkaloids into the nonpolar phase. The alkaloids don't need any help doing this, when the cells are fully lysed, and the pH is equal to/more than 2 units above the pKa

 

[Th Entity]

ha..!
Ok so breaking down plant proteins into their amino acids wont have drammatic effect if any at all.
Ok lets forget about hydrolysis of proteins, what about chemical cell lysis then?

I found very limited information of plant cell chemical lysis, when we add acid or base we lyse the cells but is there space to improve the lysing of cells while we acidify/basify? For example what would be better to lyse cells acid or base? warm/hot/boiling temperature or room temperature? For how much time? 12H 24h +?

Do you think A/B is superior to STB?

I ask those questions because if i'm going to do something, i want to do it good and correctly, i want to see if the acidification/basification and the overall extraction can be improved in some way.

 

[benzyme]

honestly, with MHRB, there's no advantage to doing A/B over STB. A/B (w/ defat) becomes more of a necessity with phalaris, maybe chacruna, because of other alkaloids present, and plant lipids. People get incredible product with STB and multiple recrystallizations, >99% pure.

most people start from powder. let it sit in a basic solution at room temp for a couple hours, shake/stir, add your nonpolar, separate. repeat the pulls two or three times. you can pour the pulls into a glass* container with epsom salts to absorb any residual basic water. evap in a dish with a fan blowing over it, and when the volume has decreased considerably, pour into a small glass* container, and put that in the freezer.

* any glass used should be borosilicate, as it is largely inert, and has a decent thermal expansion coeff. Quartz glass if you are a baller (I am not..that stuff is expensive).

 

[Th Entity]

i read some cell lysis procedures (from internet) and it seems plant cells break in no more than 10-20mins in 70-90 C at a pH of 8, do you have any idea why some teks recommend the acidification/basification step should last more thann, lets say 1hour? (Some leave their A/B mixes for hours 1-8-12+ hours before extracting with NPS)

 

[benzyme]

overkill.

some just like to be absolutely sure they've lysed all the cells.