Without knowing more, you would slowly add the base to your acid while monitoring the pH and stop at ~3-4 (which in the authors case was 2mol). Since you added too much, add some HCl to the solution to get back to the desired pH.
Without knowing more, you would slowly add the base to your acid while monitoring the pH and stop at ~3-4 (which in the authors case was 2mol). Since you added too much, add some HCl to the solution to get back to the desired pH.
Thank you for your reply , to answer your question, peptide coupling. Yes I understand you what you say makes since. but the literature I am reading calls for Pyrrolidine (2 mole) is slowly added to 164 ml conc. HCl in 400 g ice water and the pH was adjusted to 3-4. The literature has no more details than this. So do you think maybe the author adjusted the pH with more HCL? Sorry for my English but it is not my native tongue.
Thank you for your reply , to answer your question, peptide coupling. Yes I understand you what you say makes since. but the literature I am reading calls for Pyrrolidine (2 mole) is slowly added to 164 ml conc. HCl in 400 g ice water and the pH was adjusted to 3-4. The literature has no more details than this. So do you think maybe the author adjusted the pH with more HCL? Sorry for my English but it is not my native tongue.
No way. Pyrrolidine is not a base strong enough to produce that high pH.
Besides, I have problems reproducing the pH claimed. What you produce is a buffer (2 moles of pyrrolidine with about 1.9 moles of HCl, assuming "concentrated" to mean 36%). Wikipedia lists pKa of pyrrolidine as 11.3, so the pH should be around 10. make it ±1 because of the very high ionic strength of the solution - still no way of getting even close to 14, but also no way of getting close to 3-4. For that you will need more acid.
No way. Pyrrolidine is not a base strong enough to produce that high pH.
Besides, I have problems reproducing the pH claimed. What you produce is a buffer (2 moles of pyrrolidine with about 1.9 moles of HCl, assuming "concentrated" to mean 36%). Wikipedia lists pKa of pyrrolidine as 11.3, so the pH should be around 10. make it ±1 because of the very high ionic strength of the solution - still no way of getting even close to 14, but also no way of getting close to 3-4. For that you will need more acid.
Without knowing more, you would slowly add the base to your acid while monitoring the pH and stop at ~3-4 (which in the authors case was 2mol). Since you added too much, add some HCl to the solution to get back to the desired pH.
What are you trying to do?
Without knowing more, you would slowly add the base to your acid while monitoring the pH and stop at ~3-4 (which in the authors case was 2mol). Since you added too much, add some HCl to the solution to get back to the desired pH.
What are you trying to do?
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So perhaps they use more acid, they just start with 164 mL?
So perhaps they use more acid, they just start with 164 mL?
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but the literature I am reading calls for Pyrrolidine (2 mole) is slowly added to 164 ml conc. HCl in 400 g ice water and the pH was adjusted to 3-4.
The literature has no more details than this. So do you think maybe the author adjusted the pH with more HCL? Sorry for my English but it is not my native tongue.
but the literature I am reading calls for Pyrrolidine (2 mole) is slowly added to 164 ml conc. HCl in 400 g ice water and the pH was adjusted to 3-4.
The literature has no more details than this. So do you think maybe the author adjusted the pH with more HCL? Sorry for my English but it is not my native tongue.
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VOTE
No way. Pyrrolidine is not a base strong enough to produce that high pH.
Besides, I have problems reproducing the pH claimed. What you produce is a buffer (2 moles of pyrrolidine with about 1.9 moles of HCl, assuming "concentrated" to mean 36%). Wikipedia lists pKa of pyrrolidine as 11.3, so the pH should be around 10. make it ±1 because of the very high ionic strength of the solution - still no way of getting even close to 14, but also no way of getting close to 3-4. For that you will need more acid.
No way. Pyrrolidine is not a base strong enough to produce that high pH.
Besides, I have problems reproducing the pH claimed. What you produce is a buffer (2 moles of pyrrolidine with about 1.9 moles of HCl, assuming "concentrated" to mean 36%). Wikipedia lists pKa of pyrrolidine as 11.3, so the pH should be around 10. make it ±1 because of the very high ionic strength of the solution - still no way of getting even close to 14, but also no way of getting close to 3-4. For that you will need more acid.
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