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Author: Subject: Everyday Chemistry (provisional)
DraconicAcid
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[*] posted on 28-7-2020 at 21:37


I've got my son (a 16-year-old version of me) helping me in the lab, videoing some experiments so that this semester's social-distancing rules won't kill off our college's chemistry labs. I am very proud to be able to give him the lab experiences that I wished I could have had at that age.

In addition to lots of esterification reactions, TLC, the copper carnival, and distillations, we also prepared some hydrated copper compounds (for the students to determine the degree of hydration in). Just for fun, we decided we'd make copper sulphamate (following this prep: https://prepchem.com/synthesis-copper-sulfamate/ ), since I saw a lovely sample of it on Instagram, and copper(II) sulphanilate. The latter did not work at all- after reducing in volume, it started to crystallize and solidify as it cooled, so we didn't need to triturate it with acetone. Recrystallizing it from water/methanol gave pale blue crystals which turned white when washed with methanol- clearly not very coppery. According to this: https://patents.google.com/patent/US3321273A/en it's probably ammonium bisulphate.

The copper(II) sulphanilate seems to have worked, giving a nice green precipitate from the reaction of copper(II) acetate with sulphanilic acid (eventually- some boiling down of the solution was required. I'm hoping no hydrolysis of the anion took place).




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[*] posted on 28-7-2020 at 21:48


Quote: Originally posted by j_sum1  
Distilled some otc isopropyl alcohol. Seemed to be already high purity. Head temp held rock steady and I discarded only a couple of mL of heads and tails.

IPA is not quite the ubiquitous substance here that it is in the US. Nice to find such good quality.


Nice, did you dry with NaOH?

You can get relatively large amounts from eBay and if you want smaller quantities (ca. 250 ml) you can buy 99% isopropanol from jay car (at least in vic...). I also noticed it at pharmacies as a 60% solution but it was stupidly expensive.
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[*] posted on 29-7-2020 at 02:33


Quote: Originally posted by HeYBrO  

Nice, did you dry with NaOH?

I could say that I didn't feel the need to. But the truth is that it did not occur to me at the time. But I am not doing anything water sensitive with it anyway.

My main reason for getting it was because I needed a secondary alcohol for teaching. I had a really nice lab session with a handful of kids just over a month ago. Alcohol oxidation with acidified dichromate was one of the things covered.
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[*] posted on 14-8-2020 at 06:39


Low on ammonia solution. So I spent an evening making a batch. Finished up ith 222mL at 22%.
Nitric acid tomorrow.
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[*] posted on 15-8-2020 at 02:50


J_sum1 I am not quite ready to make nitric acid. I’m sticking to simple reactions within my limits :) Fortunately 70% nitric acid and ammonia solution are both available locally.

I’ve returned to cyanurates while waiting for more glycine; nickel carbonate and cyanuric acid have been stirring in the shed since Friday.
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[*] posted on 31-8-2020 at 22:37


do believe my CH3NH3 has turned out. No MP test, but slightly "fishy" and VERY hygroscopic. Also give a blue reaction to Simon's reagent.



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DraconicAcid
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[*] posted on 10-9-2020 at 21:05


So I was trying to get some nice crystals of copper(II) lactate, but it seems that it forms a mixture of different hydrates and/or crystallizes with excess lactic acid. So I said to heck with this- I'll precipitate it out as the carbonate. Added potassium carbonate, and got a very dark blue solution, matching the description of an anionic lactate complex that I recently read about. Bother.



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[*] posted on 11-9-2020 at 12:05


Just now I trying to make potassium iodate by permanganate method according to recipe from my high school. Right now reaction is done and I filter manganese dioxide from solution. And it is pain in the ass. I filter it through coffee filter and solution goes through incredibly slowly. Filtrate is still brown, but most of MnO2 remains in filter. After filtration I'll do another filtration through finer filter which retain fine particles of MnO2.



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[*] posted on 11-9-2020 at 17:08


Today was Cobalt day for me and the family.

I added NaOH to CoSO4, and got a nice blue precipitate.

In a separate container, I added CoSO4 to excess NaOH although the precipitate was blue for a moment, it quickly turned pink.

Gravity filtered both of them with coffee filters (blue solid filtered quickly, the pink solid filtered extremely slowly) and now letting them both dry. Will heat them both to convert to Cobalt Oxide, then I'l weigh and then add to my compound collection. I'm curious if either the pink or blue form "converts" to the other during these processes.

I also added CoSO4 to excess NH4OH, and the solution turned brown. Adding some NH4OH to CoSO4 gave a blue precipitate, like adding NaOH did.
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[*] posted on 11-9-2020 at 20:53


Co(OH)2 will react with atmospheric oxygen to produce brown CoO(OH).

Something about blue and pink form is on wiki:

https://en.wikipedia.org/wiki/Cobalt(II)_hydroxide

Brown soluble complex with ammonia is [Co(NH3)6]2+ and it's slowly oxidized by oxygen in to [Co(NH3)6]3+.




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[*] posted on 5-11-2020 at 23:18


Figured i'd see what the heck my semi-crappy vacuum gauge was doing for real, so I set up for simple vac disty with h2o.

results:
(temps are B.P,'s)("inch" figures what my gauge read)

66C showed 25"=286mmHG
73C showed 21"=354.2mmHG
88C showed 15"=535.4mmHG

Ain't been real scientific lately, so its something......




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[*] posted on 5-11-2020 at 23:56


I just evaporated hexane and boiled off any remaining 1-pentanol from about 30 mL of crude pentyl nonanoate. Next I need to wash with bicarb, water, and NaCl, then purify by vacuum distillation.



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[*] posted on 6-11-2020 at 00:02


My son and I are doing titration curves for the students to study next semester. Got a surprisingly smooth titration curve from vanillin after adding a bit of ethanol.

Also enjoying the smoothest, fruitiest crabapple wine I've ever made.




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[*] posted on 6-11-2020 at 05:22


Distilled some sulphuric acid, now I have
C40ml Az. (cloudy - remainder from the pot, not distilled)
25ml azeotropic, 350 ml c98% and 350ml c28% clean distilled sulphuric acid.

I was surprised at the difference in the dehydrating power of azeotropic sulphuric acid and the 93% to 96% drain unblocker that I'm used to,
and when hot, the dehydrating power of az. sulphuric acid is awesome - and terrifying.

Distilled using Chinese glassware and a cheap portable butane gas stove.
During tidy up I noticed a crack in the side joint of my distillation head, no other problems.




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[*] posted on 6-11-2020 at 12:45


finally made some lead carbonate from the acetate i had from ages ago. Back home from uni so got access to my home lab, whapped out the silly looking janky vacuum pump i made to filter it.

Also ordered a bunch of stuff for future projects! Soon i'll be set for sodium benzoate -> benzene -> nitrobenzene -> aniline -> dimethylaniline -> crystal violet.

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[*] posted on 6-11-2020 at 13:04


Quote: Originally posted by hasani10  

Also ordered a bunch of stuff for future projects! Soon i'll be set for sodium benzoate -> benzene -> nitrobenzene -> aniline -> dimethylaniline -> crystal violet.



Interesting pathway, I considered trying it, but after looking into it in detail, I gave up due to:
- toxicity of nitrobenzene
- difficulty in finding information on a good and readily available methylating agent for aniline

How do you plan to make the dimethylaniline?
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[*] posted on 14-11-2020 at 07:18


I distilled some fuming nitric acid this afternoon! I decided to go with a relatively small scale: 2 moles in a 1 liter flask to manage the foaming. This worked okay, but I found out that my apparatus leaks near the receiver and it turns out kek clips do not tolerate fuming nitric acid, even cold. They're made of polyacetal and I strongly suspect they hydrolyse to formaldehyde or some other nasty product.

I think I'll get a new apparatus made of a single piece of glass instead of head+condenser+receiver, it's not the first time it has become leaky at an inconvenient time. This should make distilling nitric acid much less of hassle if I don't have clouds NO2 and acid coming out of the joints.

In the end the product was obtained in 83% yield with a density of 1.518(5), which corresponds to about 95-97% concentration or 23 M.
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[*] posted on 14-11-2020 at 09:37


soxhlet extracted a 3oz can of Dollar General ground black pepper with acetone (IPA is HARD to find ATM). Obviously didn't use enough KOH to get the oils out, because i've got some nice big globs of orange-ish crap in my (poor) workup, along with some lovely yellow piperine. Might have been slightly inebriated. Haven't thrown out any of the extraction solvent yet though.

Have a beaker with some interesting stuff growing in it too--some ostensibly Benzyl alcohol I dropped a bit of K Dichromate in thats been sitting on a shelf. Smells as good as crazy it looks.

Will post pics.




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[*] posted on 14-11-2020 at 09:59


Oh Arkoma I feel for you, pepper extract is a bitch to work up. I've done it 3 or 4 times and everytime there was bunch of resinous crap in the product. I can't figure out how to avoid this completely. Maybe using dry solvents and dry pepper, using more KOH, or something else...
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[*] posted on 14-11-2020 at 10:24


Agreed. I've had my students run it through a column and it still turns out resiny.



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[*] posted on 15-11-2020 at 09:26


I have a small amount of piperine i extracted 5(?) years ago that came out so lovely. Before mechanical breakage in the ampoule they are in (from handling) had nice yellow needles.



piperine.jpg - 677kB

This is everyday chemistry too.

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I've got my son (a 16-year-old version of me) helping me in the lab, videoing some experiments so that this semester's social-distancing rules won't kill off our college's chemistry labs. I am very proud to be able to give him the lab experiences that I wished I could have had at that age.


First off, KUDOS to all teachers here. So important. I REMEMBER the names of my sixth, seventh, ninth, and eleventh grade science teachers NAMES. All the others? Not so much.

Had a moment yesterday.

This 14 year old kid that's been working at our shop (I don't do anything except take up space there these days) was with me at my house for a while yesterday, and my lab is right on front street so to speak. He was looking at it, and I started talking about it, as we are won't to do (we all like to share our favorite "drugs" <<metaphor). I started losing him quick with the O Chem shit. Had copper sulfate solution and a repurposed cell charger at hand. Said kid, you got a quarter on you? he said why. i said, give me a quarter. He had a dime, and as he watched copper deposit on it before his eyes and wanted to know the WTF? of it, i knew i had hit a home run. Also (mua-ha-ha) had tin chloride solution. Dendritic tin is even MORE amazing visually.

Yeah, that kid is hooked I hope.

Everyday chemistry at it's best!

teachers that touched my life:
Miss Astor
Mr. Gadd
Miss McEvoy
Mr. Gerofsky

Thank You all.


[Edited on 11-15-2020 by arkoma]

[Edited on 11-15-2020 by arkoma]




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[*] posted on 15-11-2020 at 10:15


Quote: Originally posted by Heptylene  
I think I'll get a new apparatus made of a single piece of glass instead of head+condenser+receiver, it's not the first time it has become leaky at an inconvenient time.


There's a simpler solution: buy stainless steel keck clips. They can be found easily on ebay,
Honestly I don't know why people bother with the plastic ones. They break after a few uses and you have to keep replacing them, other than being prone to breaking/melting in the middle of a distillation when distilling something aggressive/with a high boiling point.

[Edited on 15-11-2020 by beta4]
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[*] posted on 15-11-2020 at 11:00


Did some crystallization of a mixed ethylenediamine/ammine complex of nickel(II). Something like Ni(en)2(NH3)2(ClO4)2. Beautiful dark blue crystals. Of course I made a picture of the crystals.

In the past I have done experiments with Ni-(en) complexis, and the not fully coordinated Ni(en)2(H2O)2 complex is dark blue. I did not manage to crystallize that. I only could get the purple Ni(en)3(ClO4)2 complex. But now I think I have managed to make the ammonia analogue Ni(en)2(NH3)2(ClO4)2 from a dark blue solution of nickel perchlorate and ethylene diamine to which I added some ammonia.




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[*] posted on 15-11-2020 at 11:16


Quote: Originally posted by woelen  
Did some crystallization of a mixed ethylenediamine/ammine complex of nickel(II). Something like Ni(en)2(NH3)2(ClO4)2. Beautiful dark blue crystals. Of course I made a picture of the crystals.

In the past I have done experiments with Ni-(en) complexis, and the not fully coordinated Ni(en)2(H2O)2 complex is dark blue. I did not manage to crystallize that. I only could get the purple Ni(en)3(ClO4)2 complex. But now I think I have managed to make the ammonia analogue Ni(en)2(NH3)2(ClO4)2 from a dark blue solution of nickel perchlorate and ethylene diamine to which I added some ammonia.


Nice. I've tried making Ni(en)2 complexes with anthranilate and oxalate, but never had much luck in getting anything but the tris(en) complexes.




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[*] posted on 15-11-2020 at 11:32


Quote: Originally posted by beta4  
There's a simpler solution: buy stainless steel keck clips.

I have corroded stainless steel Keck clips with the nitric acid vapours invisibly escaping at joints.
I don't like using conc. H2SO4 to seal joints and grease is attacked by the hot nitric acid
My best option so far is ptfe tape instead of grease.
(and use ss Keck clips)




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