Sciencemadness Discussion Board

Sort of drug question

Little_Ghost_again - 15-10-2014 at 14:20

I have read the excellent write up on isolating salicylic acid from aspirin, I have a couple of questions.
Believe it or not the most common type for 15 miles!!! is the one you dissolve! Can this be used with the same synthesis as the other?

Are there other sources of salicylic acid worth looking at?

If you use the acid in something else how best to determine how much is there afterwards? What kind of quantitative tests can I do?

Sorry if it sounds dodgy it isnt, but I kind of have a idea for something floating around my head, also I seem to be getting drawn towards analytical chemistry.
I have burettes etc but fast getting bored with acid base titrations.

One last thing

Scales
I have seen sartorius lab scales reasonable price on ebay secondhand (£100) they go upto 200g and resolution 0.0001g, with a glass cage.
Are these worth it or
for accuracy what about the very old wooden case aprocathy type scales with twin balances? If I could get some weights calibrated then surely these would be a cheap way to get accurate weighing.

I am a bit obsessed with weight accuracy or mass or whatever it is at the moment

careysub - 15-10-2014 at 14:23

Robert Thompson (the home chemistry guru) recently blogged about buying a Chinese milligram scale (max weight ~5 grams maybe?) on eBay for $25 and was apparently satisfied with it.

Little_Ghost_again - 15-10-2014 at 15:00

Quote: Originally posted by careysub  
Robert Thompson (the home chemistry guru) recently blogged about buying a Chinese milligram scale (max weight ~5 grams maybe?) on eBay for $25 and was apparently satisfied with it.

5 grams might be a bit low, Those old wooden ones cant be that bad with decent masses (or are they weights?), they been used a long long time.

careysub - 15-10-2014 at 15:39

It is the Gemini-20 ($24 on Amazon right now) and its maximum weight is 20 g.

For milligram accuracy you don't expect a scale that takes a lot of mass (at least, in a $24 scale).

j_sum1 - 15-10-2014 at 15:39

You might try something like this:
http://www.dx.com/p/pocket-precision-digital-scale-200g-max-...

Mine is a similar model. There are a number of models to choose from on the site. Just check the maximum mass and the stated precision. (They seem to be changing shape and specifications all the time but as far as I can tell have the same basic mechanism. Just different cosmetic differences.)

Takes a few weeks to arrive from China but there is no postage cost. I have been more than happy with everything purchased from this site. Really cheap and quality has been good.


Edited to add,
This one seems a bit better.
http://www.dx.com/p/1-8-lcd-pocket-digital-scale-black-5kg-0...

[Edited on 15-10-2014 by j_sum1]

hyfalcon - 15-10-2014 at 15:54

This is what I use.
http://www.ebay.com/itm/OHAUS-CENT-O-GRAM-BALANCE-BEAM-SCALE...

Very repeatable time after time.

Little_Ghost_again - 15-10-2014 at 15:56

I have a couple of those types and yep I been happy with them except, you have a min of 50mg before it will register and they only go down to 10mg of resolution. I was thinking of this kind of thing
http://www.ebay.co.uk/itm/181556809240?_trksid=p2060778.m143...


or maybe this sort of thing
http://www.ebay.co.uk/itm/231357413610?_trksid=p2055119.m143...

[Edited on 15-10-2014 by Little_Ghost_again]

hyfalcon - 15-10-2014 at 15:59

Do you need that resolution? If not, don't spend your money on that.


Now the Sartorius, I might be tempted with that one.

[Edited on 16-10-2014 by hyfalcon]

Little_Ghost_again - 15-10-2014 at 16:19

Quote: Originally posted by hyfalcon  
Do you need that resolution? If not, don't spend your money on that.


Now the Sartorius, I might be tempted with that one.

[Edited on 16-10-2014 by hyfalcon]


I need to be able to make my my own primary solutions for titration, repeatability matters, I like the sartorius as well.
The really stupid thing is I was offered a better sartorius a few months back for around £70, I had £90 to spend and thought I wouldnt want or need the resolution so I got cheapo Chinese scales and glassware with the money.
Looking back I made a bad choice and should have taken the offer. But it was before I joined here and my chemistry knowledge was EVEN less than now.
I like the one you have, no electronics to fuck up and long lasting

Oscilllator - 15-10-2014 at 16:23

The only reason you would need to buy an analytical balance is if you are doing analytical chemistry, like titrations. I have a scale that goes up to 1000g accurate to 0.1g, and another that goes up to 20g with 0.005g accuracy. These two scales cost about $40 between them, and is really all your average hobby chemist will ever need.

That being said if nobody else bids on that analytical scale you should probably buy it cause its a really good deal, but if not don't bother and just get one or two cheap scales. Anything else is probably overkill.

Little_Ghost_again - 15-10-2014 at 16:27

Quote: Originally posted by Oscilllator  
The only reason you would need to buy an analytical balance is if you are doing analytical chemistry, like titrations. I have a scale that goes up to 1000g accurate to 0.1g, and another that goes up to 20g with 0.005g accuracy. These two scales cost about $40 between them, and is really all your average hobby chemist will ever need.

That being said if nobody else bids on that analytical scale you should probably buy it cause its a really good deal, but if not don't bother and just get one or two cheap scales. Anything else is probably overkill.


I did say a couple of times I want it so I can get more acccurate results for analytical chemistry.
I want to be able to do titration knowing I have at least given the weighing of the primary solution my best shot. and some these scales dont go for much money so seems to make sense to me.

Chemosynthesis - 16-10-2014 at 04:00

This isn't a "drug" question in the sense most people mean. "Drug questions" on the forum are illicit in nature. Last I checked, Polverone and the servers were located in the US and thus deference was given to US law on the matter, but this is not questionable at all.

I am not sure how you would determine the difference between salicylic and acetylsalicylic acid at home, so make sure you try to convert to one or the other for ease of measurement.

Amos - 16-10-2014 at 04:32

Quote: Originally posted by Chemosynthesis  
This isn't a "drug" question in the sense most people mean. "Drug questions" on the forum are illicit in nature. Last I checked, Polverone and the servers were located in the US and thus deference was given to US law on the matter, but this is not questionable at all.

I am not sure how you would determine the difference between salicylic and acetylsalicylic acid at home, so make sure you try to convert to one or the other for ease of measurement.


Yeah, don't try to make this thread sound more sketchy than it is. If your salicylic acid that you're purifying is going to be used as a drug still, maybe. Even if it started as a medication, typically you'd still call aspirin or salicylic acid a reagent.

aga - 16-10-2014 at 08:38

Reagent is a strange word, so much so looked up the etymology :

"New Latin reagent-, reagens, present participle of reagere to react "

It's not a recycled Agent at all.

Little_Ghost_again - 16-10-2014 at 09:52

I wasnt sure what to call it, aspirin to me is a drug, I want the salicylic acid for soap! so I didnt know what to call it, the reason for the question is topically applied salicylic acid can be absorbed into the blood stream,
There are several soaps on ebay that use it with sulfur, IMHO this is pretty dangerous, I have a bar and it isnt great soap! I want to try and better this as well as test the soap I brought.
My main question was if the method in prepublication would equally apply to dispersable aspirin as it obviously contains other ingredients, it just happens that getting bog standard aspirin around here is as hard as getting a sodding plumbing fitting!
I have checked and double checked and soap should contain no more than 4.5mg of salicylic acid.
There was no intention to make the thread sound dodgy, but I just stated a fact that I was after information on a OTC drug (aspirin).
Why is everyone so touchy about the D word? You dont walk into a shop and buy a packet of aspirin reagent...OR maybe you do
Unfortunately the balance isnt looking likely now, I spent the money on something else. But the question remains does the extra additives in disovleable aspirin make any difference?
One is citric acid and the other I cant make out on the packets.

hyfalcon - 16-10-2014 at 10:10

LG, check with your local veterinarian. One that deals with horses should have all the aspirin you should need. Should be able to buy it by the pound from them.

Chemosynthesis - 16-10-2014 at 10:31

Personally, I have nothing against drugs, at least inherently. I work with them all the time, but in a different connotation than most people use the term for here, in the illicit sense; the only problematic chemistry on the forum is one of legality and chemical restriction. I have yet to run into any scientologists or teetotallers on here who advocate a philosophy of a problem on all pharmacophores. It's kind of like the distinction between calling a pharmacist or a physician a drug dealer, which some people do, ignoring some of the distinctions between the two in favor of some similarities.
Aspirin is a pharmacologically active compound, absolutely. It's marketed as a medicinal compound, check. Either of these can qualify it as a drug by denotation, but due to connotations on the scope of the forum (almost exclusively chemistry), and even within the pharmaceutical field, the term can sometimes be eschewed. There is nothing incorrect about calling this a drug question, but it is a little unusual in that the majority of medical practitioners wouldn't think of a chemical descriptor or synthesis if told you had a "drug question."
Similarly, being a hobby chemistry forum, a question on drugs immediately brings up illicit connotations because the quantitative analysis, degradation products, and toxicological repercussions are outside the hobbyist's ability. And a simple extraction may yield degradation products. I know some researchers who publish exclusively on what drugs degrade to when left in a glovebox on a hot day, or in a small amount of water on a balcony exposed to sunlight, etc. They do it very quantitatively, and have shown that some inert binders and active ingredients alike can change very rapidly under some common environmental conditions. Due to this, and the questionable purity of some reagents used in hobby chemistry, consumption of products is not advised as you would no longer meet government regulations for such use.

Little_Ghost_again - 16-10-2014 at 10:50

Quote: Originally posted by hyfalcon  
LG, check with your local veterinarian. One that deals with horses should have all the aspirin you should need. Should be able to buy it by the pound from them.


LOL never thought of that!!
Who would of thought vets get so many headaches they need that amount of aspirin :D:D

@ Chemosynthesis

You are probably completely correct in every way, the truth is I have zero contact with illicit drugs, I goto a school of nearly 1400 kids and yet I have never heard of or seen any drugs at school or elsewhere, I have smelt one at certain county shows but thats about it.
So when people talk of crystal meth and other exotic sounding stuff, to me its not that real. Most on here who looked up my post code from my old nickname know how isolated my community is, I am 60 miles from a city and even thats a small one.
Maybe illicit drugs are a big problem, I wouldnt know. In 14 years I have never seen someone off there heads on something the doctor hasnt given them.
So forgive me if it all seems so far away from reality, Growing some plants in a loft I can get my head around, but people making some of the other stuff I am not sure I actually believe it goes on that much, I am not saying it dosnt, I am saying for me its a big leap of imagination.
Before its mentioned yes I live in a bit of a bubble and I am thankful for that at times. except of course when trying to get decent aspirin.!!

And for those that are concerned about me using or selling it in soap, I am not.
I want to try it against something else using myself as the subject.
I prefer my soap 100% natural (ish) :D

Chemosynthesis - 16-10-2014 at 11:34

Little_Ghost, there is nothing to forgive at all. I just don't you to feel the need to defend your inquiries since they aren't questionable at all in terms of forum guidelines. I am actually glad to see you post since I wish I had the same opportunity at your age, but was without either internet or a nearby library, and wish I could have pursued the same kind of fervor for knowledge at your age rather than whatever it was I did.

Little_Ghost_again - 16-10-2014 at 12:46

Quote: Originally posted by Chemosynthesis  
Little_Ghost, there is nothing to forgive at all. I just don't you to feel the need to defend your inquiries since they aren't questionable at all in terms of forum guidelines. I am actually glad to see you post since I wish I had the same opportunity at your age, but was without either internet or a nearby library, and wish I could have pursued the same kind of fervor for knowledge at your age rather than whatever it was I did.

Funny thing is I have the internet but no decent library for 80 ish miles! I love books, I have found a new load on ebay but having to save for them. managed to get 14 books together and do a deal for £30 odd quid, cleaned some tractors yesterday but thats been spent.
Not been allowed out today much so no cleaning!! Annoying as this is now the start of my busy season :D.
No one cleans tractors like me ;), I even clean the cabs out

macckone - 16-10-2014 at 13:04

Salicylic acid can be obtained from methyl salicylate (aka oil of wintergreen)
https://users.stlcc.edu/mhauser/Hyd%20Methyl%20Sal.pdf

Methyl salicylate is available in large quantities with no questions asked.

macckone - 16-10-2014 at 13:11

Not sure if this or a similar product is available in your country:
http://www.neutrogena.com/product/body+clear-+body+wash.do

Little_Ghost_again - 16-10-2014 at 13:35

Oil of winter green I can get, I might try the disolveable aspirin after I have used one of the others and had a bit of practice, I love the crystal shape as well.
Also found a source of hydrogen peroxide (my farm store), they know us and have no problem handing over the conc stuff.
ACpure wouldnt sell dad any even with a LTD company! very bad attitude, they want to know the reason and use and everytime you change the use you have to fill the form out again!
Never ceases to amaze me what the farm supply place can get, and its only 3 miles away!

macckone - 16-10-2014 at 14:30

When I took organic chem one of the labs was actually the oil of wintergreen to aspirin. And it was the all organic variety :(
So there were several purification steps.

j_sum1 - 16-10-2014 at 14:34

If you look up MrHomeScientist's youtube channel he has a nice little vid on the synthesis of oil of wintergreen from aspirin. You might be interested.
(Sorry, insufficient time to look it up at the moment.)

Little_Ghost_again - 16-10-2014 at 15:26

Cheers I will go have a look :D

j_sum1 - 16-10-2014 at 16:52

Oil of Wintergreen by MrHomeScientist

Little_Ghost_again - 13-11-2014 at 11:27

Quote: Originally posted by j_sum1  
Oil of Wintergreen by MrHomeScientist


I forgot to come back to this, I now have aspirin (not that much, 70 350mg tabs. Buts its enough to mess with), I got some in the end from a supermarket, I found the home brand ones that were silly cheap had little in the way of added crap in :D.
The only trouble is in the UK you are only allowed to buy a max of 32 painkilling tablets from a supermarket in one day! Its to stop you overdosing!!!! Obviously those that try and kill themselves with tablets havnt worked out there are other ways to do this.
Oil of wintergreen was a great write up and I will be doing this next week :D

chemrox - 13-11-2014 at 17:15

Don't buy used electromechanical balances unless you can find the service manual for the model listed. I have several that are DOA because the manufacturer switched to using transducers. So-called modern balances are in reality "scales." They work on transducers instead of weights. Anyway after an accurate balance has been moved or shipped it needs service. I bought a set of calibration weights to no avail-no manual available. Only thing I can add is please boycott Metler!

Little_Ghost_again - 14-11-2014 at 03:59

I have a couple of cheap scale that are electronic. One measures to a max 300 grams and can measure to 30mg. Above 30mg it has 10mg resolution.
The other has a maximum of 5kg and a minimum of 100mg. Its resolution is 100mg. No idea just how accurate they are. I will at some point get decent pharmacy scales probably mechanical and very old. I will then invest in some decent masses and have them calibrated.
Or buy a decent set from a uni second hand but in calibration. What ever path I take I want scales that will last. That way at least my results will be constant.
I sort of prefer the large wood and glass case types from long ago. With decent masses they are hard to beat.
Also because I have so much contact with a good hospital I have made friends there that have said they can check my weights with there pharmacy scales, so I should be able to make a calibration curve.
LG

arkoma - 14-11-2014 at 04:15

one cubic centimeter of water = one gram. I use an insulin syringe marked out to 100 units per CC to determine small bits of mass with my "ghetto" balance.

For instance, 5 "units" of water is 50mg. Of course, I am disallowing slight variations in density due to temp.

Little_Ghost_again - 14-11-2014 at 04:37

I forget the simple ways! I have pipettes etc that hold 1ml with 100 units marked. Also have access to RODI water. So mechanical balance would be ideal. Volume wise I can measure accurately down to 1um as I have some old glass disposable pipette things with micro bore glass tubes.
Easy to get to hung up on accuracy. For most things 10mg is plenty

arkoma - 14-11-2014 at 04:53

SI units were figured out by the French in the midst of a bloody revolution---well before "modern" gizmos.

deltaH - 14-11-2014 at 23:14

Little_Ghost_again, if you're planning to use the salicylic acid in soap, why not just crush up aspirin tablets of the required amount and mix it in with your lye when saponifying. The acetlysalicylic acid will hydrolyse under the extremely basic conditions quite rapidly. Base catalysed hydrolysis and saponification are very similar (the latter being a 'special case' where the ester in question is a lipid or ester of a fatty acid. Acetylsalycilic acid is also just an ester and will hydrolyse with lye. What you're left with will be sodium salicylate and some sodium acetate and the inert fillers used in tablet making. At the concentrations you intend to use it in the soap, these minor and harmless impurities will really not matter.

acetylsalycilic acid(aq) + 2NaOH(aq) => sodium salycilate(aq) + sodium acetate(aq) + H2O

[Edited on 15-11-2014 by deltaH]

Little_Ghost_again - 15-11-2014 at 03:16

Quote: Originally posted by deltaH  
Little_Ghost_again, if you're planning to use the salicylic acid in soap, why not just crush up aspirin tablets of the required amount and mix it in with your lye when saponifying. The acetlysalicylic acid will hydrolyse under the extremely basic conditions quite rapidly. Base catalysed hydrolysis and saponification are very similar (the latter being a 'special case' where the ester in question is a lipid or ester of a fatty acid. Acetylsalycilic acid is also just an ester and will hydrolyse with lye. What you're left with will be sodium salicylate and some sodium acetate and the inert fillers used in tablet making. At the concentrations you intend to use it in the soap, these minor and harmless impurities will really not matter.

acetylsalycilic acid(aq) + 2NaOH(aq) => sodium salycilate(aq) + sodium acetate(aq) + H2O

[Edited on 15-11-2014 by deltaH]



Really sorry I seem to have a habit of causing utter confusion!
The aspirin isnt for soap or soap related.

Some of the things I do are simply for learning or doing and this is one of them. Having said that....Hmmmm aspirin soap!!! Now theres a thought :D