Author Topic: Short Questions Thread  (Read 10820 times)

2bfrank

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Re: Short Questions Thread
« Reply #80 on: August 07, 2009, 01:03:26 PM »
Yeah a fair few things have been explored, plus whether or not a mix, that one may ultimately end up with, if not able to separate, whether such a mix would ultimately be detrimental for ones uses. I am just thinking this a little more, rather than throwing out ideas.

I would say not being able to separate waste product from desired product would be pretty detrimental to one's uses no matter what they may be! :D I don't frequent WD, has anyone had real success with it (I'm mainly wondering about the separation at the end)?

the procedure with the issues, has the issues cause the procedure is either ignorantly done, and done in the hope it is good, or worse, a deliberate and intentional, bullshit take on what I'd say has been peer reviewed, and as stated in the article aa seperated at their pI point, Mr Murphy earlier was kind enough to make sure I and perhaps others did understood what the isolectric point of a compound is and all in all the prep looks real good. YOu said you dont go to that other forum. Obviously thats your choice, but 2b feels that a member I think called Nafone pushed the thinking of this around, and Some wizard dude said something interesting regarding the addition of a solvent that might help crash out the zwitterion, Just so you no, without going over their, well the original take added sodium hydrozide to solution of H3PO4. and that was in order to establish a buffering enviroment that was slightly acidic. If you cant work out the problem that was just written, and 2b reasontly got confused with something way less easy, but if you dont get it, perhaps look up buffers and adding those reagants together. Or ask and I wont at all mind explaining, THe last time I said that, I think it was to an experience synthetic chemist, HA< it was cool, he understood, that 2b dont give a flying fuck, We all know lots of different things, and lets all kick ass, As 2b Frank read not that long ago and totaly fucking agrees. LONG LIVE THE VESPIARY> pleased, fucking blitzed to be involved. /.

2bfrank

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Re: Short Questions Thread
« Reply #81 on: August 07, 2009, 04:45:09 PM »
2b did some buffer equations, and tried to determine the pH that would likely occur if indeed one uses the
16ml of 85% H3PO4
9.5g of NaOH  that is being used for the N-methylalanine prep.
in H2O
16 ml 85% H3PO4
9.5g NaOH
so H3PO4  =  1.685g/ml  and at 16 ml =  26.96g/16ml and at 85% = 0.85 X 26.96 = 22.912g
and mr is 98g/mol = 0.233 moles

NaOH = 40g/mol  at 9.5g = 0.2375 moles

pKa  of  HPO4(2-) = 16.67
pKa of H2PO4(-1) = 7.21
pKa of H3PO4   =  2.12
0.237     0.237     0.699   0.233                 0.237             0.462         O.233
Na+  +   OH-   +  3H+   PO4(3-)    .>>> Na+   -   +       H+      +    PO4(3-)
   0.299       0.233                  0.0699                         O.233
                 H+     HPO4(2-)  >>>>    H+                  +     H2PO4(1-)
     0.0699         0.1631
                H3PO4    +  H2PO4(1-)
pH = 2.12 +   log (0.1631)/(0.0699)        Re tet initial 1mM, X 100 = 0.1 mol, 2 ex additive = 0.2mol of SMP
pH = 2.4879                                            Compare that pH to the buffered pH created by only NaH2PO4
                                        H2PO4(-)  +  H2O   .>   HPO4(2-)   +   H3O+    ILl finish later,
anyone interested, its late, maybe hes blundered.                
   The difference if correct is going to be huge, in fact it appears that very mild conditions caused by 30deg etc. The pH for the tet article would be H3O+  = Ka X a/b

 so Ka from google for H2PO4(-) and HPO4(2-) equilibrium constant baring in mind Im getting standard 25 deg, so       pH   =    6.3E-8 X .2/.2
                   pH =      6,8 X 10^-8
                   pH =       -log(6.8E-8)
                   pH =  7.16     and Frank, just realised that the acid must come from the carboxy goup which has a pKa of 2.34, at 10 g, Mr = 89g hence is  0.1 mol hence at the established pH from the buffer, all of alanine is going to deprotanate hence
                                                                                     0.1               0.2                     0.2
0.1      exces        o.1        0.1                          hence   H3O+    +    H2PO4(-)     +   HPO4(-)
RH  +     H20   =    R-   +   H3O+                                        0.3                          0.1
                                                                         so  =        H2PO4(2-)        +    HPO4(-)    

                                       pH  =   pKa  + log b/a

                                       pH  =  7.21   + log 0.1/0.3
                                       pH  = 6.73 Looking good,      So 2b feels that the way to do this prep, is to add the soliid MSP and he will double chieck his calculations and sort out a prep and present hopefully a much revised procedure based on the Original prep.

2b               
« Last Edit: August 07, 2009, 05:59:48 PM by 2bfrank »

Vesp

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Re: Short Questions Thread
« Reply #82 on: August 08, 2009, 06:50:07 PM »
Manganese persulfate has been looked into, but have other metal persulfates? Can aluminum, iron, copper, nickel, magnesium, or some other ones exist as persulfates, and have oxidizing properties similiar to that of manganese persulfate?

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poisoninthestain

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Re: Short Questions Thread
« Reply #83 on: August 08, 2009, 07:07:53 PM »
Manganese persulfate has been looked into, but have other metal persulfates? Can aluminum, iron, copper, nickel, magnesium, or some other ones exist as persulfates, and have oxidizing properties similiar to that of manganese persulfate?



From what I understand yes. I think we used iron persulfate once in lab.


Vesp

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Re: Short Questions Thread
« Reply #84 on: August 08, 2009, 07:39:26 PM »
For what?
I think I may try out a few persulfates just for fun when I get the chance.
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poisoninthestain

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Re: Short Questions Thread
« Reply #85 on: August 08, 2009, 10:59:15 PM »
For what?
I think I may try out a few persulfates just for fun when I get the chance.


Something with oxidation of alcohols last semester IIRC.

poisoninthestain

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Re: Short Questions Thread
« Reply #86 on: August 13, 2009, 03:10:14 PM »
What software do you guys prefer using for drawing mechanisms?

I've been trying out a few and they all seem to suck. Not very user friendly.

Sedit

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Re: Short Questions Thread
« Reply #87 on: August 13, 2009, 03:32:13 PM »
I use chem sketch but thats mainly because I have been using it for over 10 years  now and kind of grown accustom to it.
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Vesp

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Re: Short Questions Thread
« Reply #88 on: August 13, 2009, 07:21:39 PM »
I use chemsketch as well.
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heisenberg

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Re: Short Questions Thread
« Reply #89 on: August 13, 2009, 07:45:39 PM »
I'm another chemsketch user. It's simple and produces good quality images.
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basstabone

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Re: Short Questions Thread
« Reply #90 on: August 14, 2009, 01:58:11 PM »
Haha gonna be a little different here. I like MarvinSketch a lot. Its free and you can still do some pretty cool things with it!

Douchermann

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Re: Short Questions Thread
« Reply #91 on: August 15, 2009, 04:40:00 PM »
Hmmm, anyone see a problem with this reaction scheme if you substitute methylenedioxybenzene with dimethoxybenzene?

http://www.erowid.org/archive/rhodium/chemistry/piperonal.nitronate.html

Once to the 2,5-dimethoxybenzyl chloride, a sommelet is a walk in the park.  A very OTC method if you ask me (campachem = paraformaldehyde), considering dimethoxybenzene can be produced in good yeilds from sodium methyl sulfate and hydroquinone (according to the hive).

Vanadium

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Re: Short Questions Thread
« Reply #92 on: August 16, 2009, 06:37:36 AM »
Hmmm, anyone see a problem with this reaction scheme if you substitute methylenedioxybenzene with dimethoxybenzene?

http://www.erowid.org/archive/rhodium/chemistry/piperonal.nitronate.html

Once to the 2,5-dimethoxybenzyl chloride, a sommelet is a walk in the park.  A very OTC method if you ask me (campachem = paraformaldehyde), considering dimethoxybenzene can be produced in good yeilds from sodium methyl sulfate and hydroquinone (according to the hive).

I see no reason why it wouldn't. It may be easier to just run a duff reaction on it though. There's a greater possibility for overalkylation with your particular substrate but it's still rather remote, especially if you use the Duff.

I use pubchem's structure search and take a screenshot. Just don't have the motivation to buy/pirate software.
« Last Edit: August 16, 2009, 06:46:37 AM by Vanadium »

Douchermann

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Re: Short Questions Thread
« Reply #93 on: August 16, 2009, 06:46:41 AM »
Well a duff needs a hydroxyl to be on the ring somewhere, so unfortunately that gem wont work... sadness.

Vesp

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Re: Short Questions Thread
« Reply #94 on: August 16, 2009, 06:58:58 AM »
I use pubchem's structure search and take a screenshot. Just don't have the motivation to buy/pirate software.

Chem sketch is free so there is no need to buy or pirate. either way works, but it can turn it into a bunch of different documents. PDF, etc.
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Vanadium

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Re: Short Questions Thread
« Reply #95 on: August 16, 2009, 07:19:07 AM »
^Nor the motivation to use it for free. I don't use it that often anyway.

Well a duff needs a hydroxyl to be on the ring somewhere, so unfortunately that gem wont work... sadness.

So just do it before you methylate then. I think I saw a ref where it did but I'm not sure on that. I'll get back to you.

Douchermann

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Re: Short Questions Thread
« Reply #96 on: August 16, 2009, 07:48:11 AM »
Aye that I know will work.  The problem is, the methylating agent I want to use (sodium methyl sulfate) has been reported to not work on 2-hydroxyl-5-methoxybenzaldehyde, which would cause the need for a more elaborate methylating agent such as methyl tosylate or *gasp* MeI/DMS.  However, sodium methyl sulfate can effortlessly turn hydroquinone into dimethoxybenzene.  I'm going to attempt to methylate the formylated product with NaMeSO4 first, but if that fails, I'm going to have to try to work with what I have.

2bfrank

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Re: Short Questions Thread
« Reply #97 on: August 17, 2009, 03:29:35 AM »
Anyone know anything about converting formalin > paraformaldehyde.... It was suggested HCl conc would catalyze the polymerization.. I just wanted to hear if their is anymore detail with this.. OBviously I can play around, but time is ticking, and I got a shitload of much more interesting things to be doing, but I do need the solid Para, so it be appreciated if any more detail could be thrown my way......

Douchermann

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Re: Short Questions Thread
« Reply #98 on: August 17, 2009, 03:41:58 AM »
I've done it a couple times with conc. H2SO4.  However, it was mostly in test tube quantities.  The results are also very sporadic, sometimes it works, sometimes it doesn't. Here is a success:

http://127.0.0.1/Douchermann/imgs/p-formal.JPG

2bfrank

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Re: Short Questions Thread
« Reply #99 on: August 17, 2009, 05:19:08 AM »
Thanks Doucherman,, the Ttube has a stopper, does this imply that you have sat it in a solution with heat, or something?