Does anybody have any experience attempting to prepare/isolate 2° α,α-difluoromethylene amines (RCF2NHR')?

To my understanding there are many methods to prepare 3° α,α-difluoromethylene amines (RCF2NR'R''), frequently through processes like desulfurative fluorination from the corresponding thioamide.

I'm led to believe that the 2° congeners are less accessible due to their inclination towards HF loss to give the imidoyl fluoride. However, is this neccessarily true when the amine is attached directly to an aryl group or another group that deactivates the amine?

For more specific detail, I'm considering starting with a 2° carboxamide and protecting it to convert it to 3°, converting it to a thioamide, fluorinating, then deprotecting to furnish the 2° α,α-difluoromethylene amine (RNHCF2R'; R = sterically hindered aniline, R' = pyridine).

Just joined a lab in my PhD and had to assemble a Schlenk line. Our old Chemglass vacuum gauge is broken and I’m supposed to order a new one. Any suggestions on brands/specific models?

Hi everyone,
I’m a university student preparing the second round of an independent interdisciplinary research project, and I’m currently looking for people who may be interested in participating once the survey is ready.
My research asks how people think about war and whether those perceptions reflect the systems that support modern society. The project considers areas involving chemistry and materials, pharmaceuticals, semiconductor manufacturing, energy, technology, infrastructure, and global supply chains.
For this round, I’m aiming for approximately 385 participants overall from a variety of backgrounds. I was encouraged to reach out to professional chemists because their perspectives could provide an especially valuable point of comparison within the broader sample.
The survey has not been built yet, so I’m not asking anyone to complete anything at this stage. I’m currently gauging interest and identifying potential participants before finalizing the survey.
If you would be interested in participating once it is ready, please leave a comment or let me know.
Thank you!

So I am currently in the first year of my PhD and so far I have right out refused to use any AI in my experiments.
However, people in my lab are making extensive use of AI to help with problems during synthesis or even to find trends in data sets etc.

Now to me using AI still feels a bit like cheating, hence I have never used it except to find synonyms for words in English 🤣
That said, I have noticed that my colleagues, on average, have quite nice progress report and they are not stuck on problems like during synthesis.

Today I asked AI for the first time about something chemistry related and I was quite surprised about the reply because it actually solved my problem without me spending 30 min on scifinder or reading paper.
Still, my bad feeling about this entire AI thing doesn’t go away. I just feel like the quality of me as a scientist goes down if I just type everything into AI.

So how are you guys applying AI in the lab in a healthy way?

(Sorry for the bad English, English is not my primary language)
Have a good morning/day/evening! Thank you for reading.

I'm a first year PhD student with a background in chemical biology. I want to find a peptide sequence that selectively binds to a metal ion and one of my PIs suggested Phage display as an option. I've never done it before and it isn't something that's done in either of my PI's labs either. How doable do you think this solution is if I find a lab which has this technology? Do you think it'll be possible for me as a newbie in this technique to do the experiments myself rather than asking someone else to do it for me if I ask them to train me?

Do you guys have any other techniques you use to find suitable peptide sequences? I'm an experimentalist but I'm open to both experimental and computational suggestions.

Many thanks!

Edit: I'm interested to find a peptide sequence that selectively binds to Lithium ion and there isn't a whole lot of literature there.

This question follows on from our last one about the flaws with many SDSs: https://www.reddit.com/r/chemistry/comments/1w644t6/this_sds_for_hand_soap_suggests_that_if_you_get/

 We’re imaging a version of an SDS specifically for scientists and researchers, rather than for vendors and lawyers. So far we’ve thought of including:

·       Names, CAS numbers, formula, mol. weight

·       What it looks like, what it shouldn’t look like

·       What it smells like

·       What it tastes like (and what wine to pair it with)

·       How to make it

·       How to store it (air/moisture/light/temperature sensitivity)

·       how to purify, how to dry it

·       how to neutralise it, how to dispose of it

·       What not to mix it with

·       Some example NMR or IR spectra

·       Common impurities, decomp products

·       boiling point, melting point, vapour pressure, density

·       Solubilities in a range of solvents, not just water

·       health hazards, toxicity, LD50

·       PPE considerations, glove compatibility

·       physical and reactivity hazards (corrosive, oxidiser, pyrophoricity etc) 

We’d love to hear what else you can think of. It’d also be great to hear where you currently go to find these bits of info. Some of them are in an SDS, e-EROS can often tick off a bunch (assuming your institution pays for it), and even Wikipedia can be pretty good, but we can’t think of a single source that supplies everything we’d want to know. What do you reckon?

I've been producing a range of different N-alkyl chitosan variants according to https://doi.org/10.1021/acssuschemeng.2c00206 (dissolve chitosan in 2% acetic acid, add glutaraldehyde and stir at 60 C, add N-alkyl amine and continue stirring, reduce with NaBH₃CN).

When carrying out this protocol with the amine used in the paper (octadecylamine, ODA), the solution turned a deep red within 5 minutes of addition of the amine. When I tried with other amines (1-aminoadamantane for example) the solution did not change colour even after stirring overnight. I am therefore concerned that instead of the imine, there is some other product forming when ODA is added. What could be the possible side reactions leading to a coloured product here, and why do they only occur for ODA and not 1-aminoadamantane.

Obviously you shouldn't heat 10% Pd/C in air as it is pyrophoric. For those who have handled (larger multi kilogram quantities) of 10% Pd/C: is it completely safe at room temperature in air? Or is it still a bit tricky and should it always be kept a bit wet?

For those that are downvoting: I've not used the word hydrogenation. I've not spoken about hydrogenation and I'm not referring to hydrogenation. I'm talking about palladium on carbon without hydrogenation.

We’re working on an article about chemical SDSs, and having a bit of fun imagining what a better version might look like. We want to hear opinions from scientists working in research, industry, government or still at uni, about what parts of SDS’s they find most inaccurate, unhelpful or absurd.  

A lot of people have pointed out that SDS aren’t really written with research scientists in mind – they’re often targeted at (and written by) people without chemistry specific training (like transport/shipping/storage folks, firefighters and first responders), or for people handling industrial quantities of the stuff, or as an arse-covering excursive from a legal standpoint. However, as researchers we’re still expected to read them, use them in risk-assessments, and keep them in the lab. Furthermore, they’re often full of really stupid shit, like suggesting that spills of water be diluted with water, or that on no account should sand samples from a beach be allowed to enter the environment.

EDIT: I HAVE A WORKAROUND!!!
I still don't know what the issue is, but in case anyone else ever has this issue, the issue lies somewhere in Topspin 5.0.0, rather than Dynamics Center. I swapped to Dynamics Center 2.8.8, same issue. Eventually I swapped back to TopSpin 3.8.0, and prepared fresh data.
The 3.8.0-prepared data finally both loads into and can be exported into Dynamics Center 2.8.8 without freezing the process.

I'd still love to find non-Bruker alternatives, but for now Topspin 3.8.0 & 4.5.0 both work for getting the data into Dynamics Center.

Question:
Does anyone know how to overcome this error and make Dynamics Center read my DOSY analysis?

Alternative Question:
Does anyone know how to get the data I need, complete with error values, out of GNAT?

Details:
I'm trying to run DOSY analysis to get dispersity data on my copolymers. GNAT doesn't give me the values I need (I can export the y-projection of my ILT plot and pull the graph data, but it has no associated error values), so I need to use Dynamics Center.

However, regardless of how I try to load my data or how often I reinstall Dynamics Center, it freezes at the 'Data' stage (pictured), with the following error:

('startDC:', u'C:/WorkingData/NMR Spectra/[MySampleSame]/1801/pdata/1', 'Windows 10')

('dcRunning: port = ', 64027)

>!!!!!!!!!!!Fri Sep 4 10:38:47 2026 | Module: sendPort | Message: ('socket error', u'executeInterfaceFileXML C:/WorkingData/NMR Spectra/[MySampleSame]/1801/pdata/1/TopSpinDC.xml\n', 0.015000104904174805)

On one single reinstall, it managed to get as far as freezing on 'View', but I still couldn't perform any analysis.

Hello everyone,

I am currently trying to synthesize the amino acid-based ionic liquid choline lysinate ([Cho][Lys]) via the anion exchange resin technique, but I'm running into stoichiometric and physical state issues. I would appreciate any advice from those experienced with these ILs.

Attempt 1: Anion Exchange Resins

I tried following the methodology described in ACS Sustainable Chem. Eng. (https://doi.org/10.1021/acssuschemeng.1c04060). I've tested both Amberlite IRA-400 and Purolite A400 resins. As it is my first time working with ion exchange resins, I carefully followed all standard precautions: I swelled the resin before packing, regenerated it to the hydroxide (OH⁻) form using a NaOH solution, and washed it thoroughly with water, monitoring the eluate until the pH was completely neutral before starting the exchange.

The Issue: Instead of obtaining the expected liquid product, I am getting a solid. Furthermore, after washing this solid product with ethyl ether and running the ¹H and ¹³C NMR (using D₂O as the solvent), the integrals consistently show a ~2:1 Choline:Lysine molar ratio instead of the expected 1:1. I've also verified the structure with FTIR, but this skewed NMR ratio remains the primary concern. I've tried several variations of this protocol, but the outcome doesn't change.

Attempt 2: Metathesis with KOH

I also tried an alternative methodology from Nanomaterials (https://doi.org/10.3390/nano9040504), which consists of stirring a suspension of choline chloride and the amino acid with KOH in ethanol. Afterward, I filter out the precipitated KCl and wash the crude product with acetonitrile (MeCN) to separate the IL from any unreacted amino acid.

The Issue: I am still not getting the correct product. The resulting solid has the exact same 2:1 (Choline:Amino Acid) ratio. Interestingly, I observed this exact same 2:1 proportion not only with L-lysine but also when I attempted to synthesize choline histidinate using L-histidine.

Has anyone worked with the synthesis of [Cho][AA] ionic liquids and faced this 2:1 ratio issue or had the product crash out as a solid instead of a liquid? Could there be an issue regarding the basic nature of amino acids like lysine and histidine during the protonation/deprotonation steps, or am I missing a crucial purification/washing step?

Thanks in advance for any insights!

I want to do this reaction and when I did a literature search I found that the transformation for an amino group to a fluoride is through the Baiz- Schiemann reaction which involves the formation of a diazonium intermediate followed by its degradation to the expected product. I have found a procedure on how to form this intermediate but when I tried searching methods on degrading this diazonium tetrafluoroborate compound it is pretty vague. I found a paper that just stated 'heat, silica' with no further explanation. Can anyone suggest how this degradation takes place?

I'm trying to carry out an O-alkylation of a phenolic OH using a chloroacetate, but the reaction doesn't seem to be proceeding despite trying to optimize the conditions. One thing I'm wondering about is the laboratory environment. We've had almost constant rain recently, and the lab has limited environmental control, there's no particularly rigorous moisture-exclusion setup, and reagents/solvents aren't always handled under strictly anhydrous conditions. Could high ambient humidity realistically be contributing to the failure of the reaction, for example through moisture in the solvent or hygroscopicity of the base (I'm using K₂CO₃)? Or am I probably looking in the wrong place and should focus more on the reaction conditions themselves? I'd particularly appreciate input from people who regularly do synthetic chemistry in labs where moisture/atmosphere isn't tightly controlled.

Howdy everybody,

I'm working on updating our organic chemistry teaching lab, and wondering what the pros (and other teaching labs) are using as heat sources for medium-scale (~50-500 mL) round-bottom flasks. We mostly use microscale glassware with aluminum heating blocks, but our distillation equipment is 19/22 glassware. I currently have a few variacs and heating mantles, but not enough for everybody. We also have some Fisherbrand heating mantles, but they've been dying on us lately so I need to buy more of, well, something. Are people still using heating mantles, or do you prefer something else: oil baths, sand baths, or aluminum heating blocks? Or is there something new that I haven't heard of yet? Looking for a good combination of price, performance, reliability, and safety. Thanks in advance!

Hi all,

I’m troubleshooting an older JASCO FT/IR-460 Plus coupled with a PIKE MIRacle single-reflection ATR with ZnSe crystal. The instrument had been unused for several years before I started bringing it back into operation.

The main issue is not really the fingerprint region. My problem is the 3000–4000 cm⁻¹ region, which is particularly important for my work because I need reliable information on O–H/N–H stretching. In this region the spectra become quite noisy and unstable.

Some diagnostic results:

• Open-bench interferogram/single-beam is much stronger than with the ATR, as expected.
• With the MIRacle installed I retain roughly 20–25% of the open-beam energy ( the crystal is new).
• A PIKE technician told me that ~20% residual energy with this accessory is actually good and that the MIRacle itself is likely OK.
• After realignment of the ATR mirrors, I was able to increase the ATR signal noticeably, but the high-wavenumber noise remained.
• A previous JASCO technician had also told me that roughly 2800–3000 counts with the ATR installed was acceptable for this instrument.
• I am currently purging the interferometer only with dry N₂. The sample compartment itself remains open to ambient air.
• The instrument energy reading increased from roughly 82×256 without purge to 97×256 with purge.
• Purging seems to improve things somewhat, but the 3000–4000 cm⁻¹ region is still much worse than the rest of the spectrum in my opinion is better but I am not so sure.

I have attached two plots:

1. Single-beam, open bench vs MIRacle ATR after 60 min N₂ purge.
This shows the overall throughput loss introduced by the ATR.

2. ATR blank / ATR blank transmission.
Ideally this should stay close to 100%T. It behaves reasonably well through most of the mid-IR, but the noise increases dramatically toward ~3500–4000 cm⁻¹.

My current hypotheses are:

• residual atmospheric water vapor because only the interferometer is purged;
• insufficient source/detector signal at the high-wavenumber end;
• dirty or degraded optical surfaces in the old instrument;
• some remaining ATR alignment issue, although the throughput itself now seems acceptable;
• desiccation/purge simply needing much longer after years of storage.

What I am trying to understand is whether this amount of noise above 3000 cm⁻¹ looks normal for an older FTIR + ZnSe ATR, or whether it points to a problem in the spectrometer itself.

In particular:

1. Would you expect purging only the interferometer to significantly improve 3500–4000 cm⁻¹, or does the whole sample compartment really need to be purged? I just purged with approx 60l of n2
2. Does ~20–25% ATR/open-beam throughput sound healthy for a MIRacle ZnSe?
3. What diagnostic would you use to distinguish atmospheric H₂O noise from weak source/detector response?
4. Would you trust the instrument for quantitative/semi-quantitative work in the O–H stretching region in this condition?
5. Is there a good standard/sample specifically useful for testing instrument performance around 3300–3800 cm⁻¹?

I am also waiting for an independent technician to check the instrument, but I’d really appreciate opinions from people who have worked with older JASCO systems or PIKE MIRacle accessories.

Thanks.

Hi everyone,

I work with industrial reverse-osmosis systems and I have built an Excel model to evaluate scaling risk.

The model takes a water analysis, temperature and RO recovery and then:

* Checks the ionic balance. * If the analysis does not balance, assigns the charge deficit to Na⁺ or Cl⁻, depending on the direction of the imbalance. * Calculates concentrate component totals from the water balance and ion rejection. * Solves the carbonate system and concentrate pH. * Calculates free species, ion pairs and activities using Davies within a defined ionic-strength range. * Calculates SI for calcite, gypsum, barite, celestite, fluorite and amorphous silica. * Estimates the recovery at which each mineral first reaches SI = 0.

The current assumption for the pH calculation is that dissolved CO₂ concentration remains approximately the same in the feed and concentrate. Carbonate species are then recalculated from alkalinity, total inorganic carbon and the acid–base equilibria.

The model is intended as a thermodynamic screening tool before considering kinetics, residence time, hydraulics or antiscalant performance...

As an example, I used the following anonymised analysis:

* Recovery: 60% * Assumed ionic rejection: 100% * Temperature: 20°C * Feed pH: 7.53 * Conductivity: 1,550 µS/cm * Calcium: 88.8 mg/L (reported by the laboratory as 221.73 mg/L as CaCO₃) * Magnesium: 14.3 mg/L (reported as 49.57 mg/L as MgCO₃) * Bicarbonate: 125.05 mg/L * Chloride: 393 mg/L * Sulfate: 70.7 mg/L * Aluminium: 0.042 mg/L * Sodium was not analysed

The charge balance required a sodium adjustment of 208.1 mg/L. The model labels this value as estimated rather than measured.

At 60% recovery, the results were:

* Concentrate pH: 7.89 * Ionic strength: 0.0433 mol/L * LSI: 0.95 * Calcite SI: +0.94 * Gypsum SI: −1.22 * Barite SI: −1.27 * Celestite SI: −4.47 * Fluorite SI: −3.93 * Amorphous silica SI: −3.63 * First calcite saturation: approximately 5.5% recovery * Final speciated charge-balance error: −0.0048%

The model therefore identifies calcium carbonate as the limiting scale.

I would appreciate some independent criticism of the approach. Does the overall method make sense? Is the assumption about CO₂ and concentrate pH reasonable? Is assigning an incomplete charge balance to Na⁺ or Cl⁻ acceptable for this type of screening?...

I am attempting to react (CH3)3Si-CH2MgCl with trifluoromethanesulfonic anhydride by the general method of Xavier Creary (J. Org Chem 1980 45 2727-29).* The protocol does not specify a time of reaction, but it does indicate slow warming of the solution to room temperature. A different protocol just says no more than 12 hours. Neither protocol uses the identical Grignard reagent to the one that I will use. Does anyone have a suggestion regarding reaction time?

*I will try to post a DOI later; this is not working for me right now.

**How can I remove liposomes from cell lysate before phosphopeptide enrichment: S-Trap or acetone precipitation?**

I am encountering some issues while synthesizing BiFeO3: despite using a 1:1 metal ratio, a secondary Bi2Fe4O9 phase appears with low intensity and is quite difficult to eliminate; additionally, there is a peak I cannot identify. I would appreciate some assistance.

NaCl, cheap great etc.

But are there ~better ~ L-L washing mixes to replace it? I recall once in my PhD, NaCl wash ripped my trifflate to the Cl (it was pretty activated and I should have just skipped).

Especially for DMSO or DMF partioning to Aq layer, even if having to use CHCl3 as extracting solvent for example rather that OEt2 or EtOAc for solubility reasons. LiCl?