Why aren't there any limit tests für iodide in the European Pharmacopoeia?

Also, for which Ions is it sensical to do a limit test and why?

I'd be grateful for a reply :)

When I asked my chemistry teacher about it, he told me it's not as important as you think it is. Also, the 7th period is highly neglected in my country and we were told almost nothing about it. What's the reason behind it?

I read that sodium citrate at > 0.5% concentration helps prevent biofilm growth. I was thinking about adding it to my ultrasonic humidifier reservoir and my CPAP's reservoir.

But I'm not sure how much sodium citrate would be carried off in the vapor, and if so whether it would create a dust on surfaces in the room (for the ultrasonic humidifier) or go into my lungs (for the CPAP).

Or would the sodium citrate remain in the reservoir?

The CPAP humidifier works by heating the reservoir and blowing air across it before sending it down the pipe to my nose. So there are two different processes involved.

Thanks!

I’ve had this for a while now and wanted to see if anyone else had something similar to it.

I recently ran my first column using chloroform as the initial mobile phase, then switched to a 97:3 mix of CHCL3 & Ethyl acetate. After collecting the fractions compounds I added 3 ml of diethyl ethr and stored it at 4°C, but no crystal formed. Any tips on how to solidify the compound or better solvent options or any alternative methods I should try?

Since I'm new to this, I have a few Questions: -After collecting the compound from the column in liquid form, are they any steps I should take before moving on to characterization?

-Since the compound is in liquid form, if it necessary to solidify it before characterization?

Any guidance on this would be really helpful –Thanks in advance!

Why do the bubbles in champagne form as a continuous stream from points within the liquid while in beer they form on the glass surface?

Hey everyone!

I'm an entrepreneur starting a niche pet care line and am looking for a cosmetic chemist to act as a consultant who will guide us through product development. This could be done entirely remotely, and you will be compensated based off overall profit post-launch, in other words- uncapped earning potential to teach me things and answer our questions. No physical work is required.

You'll need to:

• Provide expert consultation on product formulation, ensuring safety, quality, and efficacy for pet care use.
• Offer insights on ingredient selection, safety, and interaction for creating safe, effective, and marketable products.
• Advise on product development strategies, including market positioning and formulation improvements.

I'm seeking to build a great long term relationship with this individual, that could carry on even after product launch as we explore more growth opportunities.

I believe that human relations are what drives businesses to success and am looking for someone who is like-minded and will believe in our brand as much as I do.

This will likely require consultations over phone, virtual meetings and emails on a weekly basis. NDA will need to be signed along with a compensation agreement. There are no set work times and no physical labor needed.

Please send this to someone you know who may be interested, and if this is you- please reach out and let's talk!

Brought numerous catalyst but none have seemed to work

I found a super glue in my local hardware store that contained some amount of Poly(methyl methacrylate) in formula (said it on the box).

My question is…. Why would you put this in super glue and what kind of PMMA would it be?

(Just an amateur chemist)

How do you learn reaction mechanisms, besides just memorizing? I'm taking chemistry at my university, and it is not intuitive for me. I understand the concepts of MO, hard-soft acid-base theory, delocalization, and hybridization separately, but when I see a giant mechanism, I just get super overwhelmed and stressed on exams and have trouble logicking my way through. Is that just me? How do I get better? I feel so stupid.

I'm interested in building a carbon scrubber air purifier for reducing the indoor carbon dioxide levels at home. A group called Open Air has been working on small scale carbon scrubbers. Check out their work at https://openair-collective.github.io/openair-cyan/ .

I'm not interested in taking measurements, but I am interested in reducing indoor levels of carbon dioxide, just as I've already built my own air purifiers out of fans and filters for reducing indoor levels of particulate air pollution. Opening windows will NOT be an option during the colder weeks and months that lie ahead.

The Open Air group has two designs, both of which involve combining calcium hydroxide and carbon dioxide to form water and calcium carbonate.

The first design involves suspending calcium hydroxide over water, using a small aquarium air pump to pump air into the water to make bubbles, humidify the air, and rely on a thin film of water around the calcium hydroxide particles to facilitate the carbon-dioxide-consuming reaction.

The second design is Aqueous Cyan (https://openair-collective.github.io/openair-cyan/aqueous\_cyan/), which looks much simpler. The idea is to just dissolve the calcium hydroxide in water and use the air pump to pump in air.

What do you think of these designs? What are some reasonably economical ways to enable either of these designs to consume more carbon dioxide faster? One idea I have for the aqueous design is to replace the air pump with a small centrifugal fan on top and use a tube (or short length of PVC pipe) with an aerator at the end. This tube (or group of tubes) would be the ONLY way air is allowed in. The idea is to force higher CO2-air into the water and form bubbles. The CO2 would react with the dissolved calcium hydroxide to form water and calcium carbonate. The fan would push the resulting CO2-free air out.

ChatGPT (o1-preview, the other models feel stupid in comparison to it) told me that epoxide ring can be opened by a hydroxyl group. Castor oil mostly consists of ricinolein (the triglyceride of ricinoleic acid), which has 3 hydroxyl groups per molecule.

So I decided to try curing epoxy resin using castor oil as the sole hardener. Yes, the AI warned that these hydroxyl groups are very weak nucleophiles and will likely require high temperatures and/or catalysts. But I still asked to calculate stoichiometric ratio, and it told me to use approximately 40:60 pbw of epoxy:oil, assuming ~180g (186g?) of EEW.

I've mixed the components in a PET bottle and tried heating in a boiling water. The solution was only becoming transparent (slightly yellow) when hot, instead of being white and cloudy, but showed no sign of curing. Then I carefully tried heating the bottle in my microwave oven, the PET bottle became burning to touch and started to lose transparency (likely from heat), but the liquid inside still did not cure. After few heating-cooling cycles I decided to give up.

ChatGPT told me that no reaction was likely due to secondarity of the hydroxyl group and/or steric hindrance (I could not find a 3D-model of the ricinolein molecule)

What can this community say about this experiment?

P.S. Plz be eazy on me, I only have 3 years of parochial school of education, I do not know much chemistry

P.P.S. I know that castor oil is used in small amounts as a primitive epoxy plasticizer, I wanted to use it as THE hardener

P.P.P.S. Also, tried glycerine as THE hardener, using the same heating methods. No success either. Even though, according to the AI model, glycerol's hydroxyl groups are primary and thus more reactive

Hello, I am looking for informed opinions on the Taylor Salt test kit. I used one in my salt water pool and found my salt levels to be 3600ppm. I was happy to see this and just dumped the test water back into the pool by my skimmer. I now feel dumb because the resulting reaction would have generated Silver chromate. The first reagent in the kit has Potassium Chromate which reacts with silver nitrate. I figured that 1 drop on the reagent should have 5mg or less of the potassium chromate (An educated guess based on the 10% by weight amount of the potassium chromate in 1 drop 0.05ml). My pool is just over 10,000 gallons and we swam in it immediately after I did this. My filter pump was running at 90% and I have 4 returns. I’m just curious what people think about possible excessive Chromium 6 levels after this test. By my math it should be below the threshold for drinking water. Am I correct or is there a concern that I exposed myself and family to this chemical at a higher concentration. If anyone knows the chemistry and chemicals better I would appreciate any opinion. Thanks!

Check my YouTube video and support me please 😊🙏 https://youtu.be/7OrJII0Rt_w?si=_otEAA8FU8gdib8W

Hello! In the image below, after the proton transfer (PT), why does the nitrogen not gain a positive charge if it's using its lone pair of electrons to grab the proton from the OH? Thank you!

https://preview.redd.it/o96tf2y82rzd1.png?width=541&format=png&auto=webp&s=d363ef1b5113028f149028205b7fc1ad5c84ebcf

On the Wikipedia page for the process, it states 300-400 C.

What happens in that process at much higher temperatures? Like 1000 C?

Also, does this process only work in the presence of oxygen or can it be done in a complete CO2 environment like Mars?

This might be a long shot, but am looking for some insight here!

The titrant in question is hydranal composite 5, which contains: Iodine, sulfur dioxide, imidazole, 2-methylimidazole, dissolved in DEGEE.

My medium is: 50 % comp 5 working medium (chloroform, 2-chloroethanol), 30% methanol, and 20% glacial acetic acid.

Those make up the reaction. I received some samples for water content that are supposed to be pure bis-(2-dimethylaminoethyl)(methyl)amine. They believe ambient moisture has contaminated their samples, as each sample is supposed to have <0.5% water. One of the samples I had a few issues duplicating results, but was able to get roughly 3.1% water. Their assumptions are correct. The other two samples are weird. For each of them, I was able to duplicate between 0.3-0.6%. However, they also duplicated results of 2.6-3.6% water. The higher water content data was first, so I don’t think they’re necessarily hygroscopic.

When I went to draw up the sample into the syringe for the fourth time, a white vapor (almost looked like smoke) started coming from the container and out of my syringe.

The weirdest part is post reaction. Every sample I have ever run will finish as a homogenous amber liquid. These last two samples separated into a white foam like precipitate and a clear yellow liquid. I already had to make a special medium because it is an amine. After bringing this up to the submitter, he mentioned there were concerns from the vendor that there were discrepancies with the cure kinetics. But he had no other info.

Thanks to anyone who read all of this and may be able to provide insight:)!

Hi there,

I recently purchased a sauna tent off Amazon. I trusted that this tent was built/designed to withstand the heat in the sauna (~75 celcius), but now I am not so sure. I reached out to the company that made the tent, and they've told be that the tent is made from Oxford 210D nylon, with a fireproof coating made from urethane. They assured me that it is safe to use at high temperatures, but I figured I'd ask here to see what people think. There are several brands of these tent saunas available, and all seem to use the same materials.

Hello! I'm (20F) a bachelor student doing a research project! I'm working on catalytic testing using NMR . The reaction is carried out in situ in the NMR tube and spectrums are measured periodically during 24h. The reaction is an oxidation using tBuOOH.

I track the amount of tbuooH left in the sample by integrating the peak at ~8ppm (OO-H signal). But overtime that signal is shifting to ~9ppm.

Do you know what could be causing that (the peak shifting)?

Thanks!!

I am losing alcohol products in my work up or rotovapping procedures. Typically quench reaction, extract with ether and rotovap on low setting but still losing mass balance. Anyone have suggestions on where the material could be getting lost? These are pretty low molecular weight products

Could I just concentrate my reaction use internal standard for yield? Or is the work up not the issue?

Hi everyone, I'm doing a Buchwald-Hartwig coupling reaction and I'm trying to clean it up. I think one of my impurities is an oxidized Davephos which is my ligand. Any ideas on how to remove it from the reaction mixture? My product is polar (a secondary amine)

Just a question I’m curious about. I’m having an incredibly difficult time finding an answer elsewhere.

Hi chemist peeps,

Noob here. I would like to ask if these test can offer insight or indicator if the water is safe to drink:

This is for pool strips I saw online, however, would these test help if, say, the water filter I installed is effective as to its purpose?

Thank you!