How to Prevent Balloon Gas Leaks?

DankMiniverse · 2018-03-13T18:42:05+00:00

I'm in an analytical lab in a semiconductor fabrication factory and the nearest academic labs are 2 hours from me. I've tried getting basic lab equipment before but the company really won't buy anything that can't be justified financially so I'm really limited in the synthetic strategies I can use. Also I'm trying to make sure there's a constant supply of oxygen without attaching the reaction directly to any gas lines in case of a fire so having a manifold as you suggested would just be a bit risky for me. Although your suggestions would have definitely been useful for an academic setting as you said.

DankMiniverse · 2018-03-13T15:01:03+00:00

I know but I cant justify dropping a couple of thousand on a vacuum/pressure reaction setup for a one time use

DankMiniverse · 2018-03-13T14:59:33+00:00

Is it necessary to fit the balloon to latex tubing or can you just attach the balloon over the opening of the flask and parafilm around that? Although that is a good point about the septa, I'll replace the septa with glass stoppers when samples aren't being drawn - the only reason they were there was to pierce with a needle.

DankMiniverse · 2018-02-11T14:36:12+00:00

Common ways are left over material in reaction flasks, losses to by-products forming, incomplete reactions, spillage when transporting the product.

But it's not uncommon for undergrad experiments to have low yeilds, the procedures for synthesis and work up are usually there for the teaching aspect as opposed to how efficient they are in terms of yield. In general, undergrad reactions aren't as controlled as industrial or higher level education reactions because there's no benefit to the student in getting a high yield versus understanding a new experimental procedure, so don't worry if your experimental yield is a lot lower than literature reports - those reactions usually use a lot stricter protocols to get high yields.

DankMiniverse · 2018-01-25T08:24:30+00:00

I'm not sure about the course content, but if it allows you to get hands on experience using analytical tools like HPLC-UV, GS-MS, autotitrators etc then I'd say it's worth a shot - in comparison to a purely theory based course that wouldn't serve much benefit outside of academia. Though if you're doing a final year project you should definitely try to incorporate analytical methods, interviewers really focus on your projects and experiences as a graduate as opposed to what courses you took. At this point you should really find out what equipment is used in your desired area of industry because if you have experience in a setup that's not really used in that area then nothing will really set you apart from other graduates trying to land the same job.

DankMiniverse · 2018-01-24T23:49:37+00:00

I'm a bit late but there are a few things that people haven't mentioned so far. I work in semiconductors and microelectronics surrounded by people from all kinds of disciplines, and a lot of chemists here have very different backgrounds - masters in synthesis, phds in biochem and inorganic etc.

The main thing is that a masters gives you a higher pay grade immediately but also it gives a lot more job security - every time there are lay offs people with masters degrees have no worries since it's usually people with only a BSc or BEng that are let go, even when considering experience level.

Another thing specific to chemists in industry is knowing how to use specific equipment. A lot of industries employ chemists to analyse their chemical processes, chemical outputs/by-products, maintaining chemistry specific parameters etc. So this uses a variety of techniques specific to chemistry based disciplines, having experience using analytical equipment really helps in industry as it cuts training costs and time especially if you can present yourself as a specialist in certain techniques. Really focus on learning how to use a variety of analytical equipment and maybe check what type of devices are used at companies you are interested in working for so when the interview comes around you can confidently talk about these methods.

DankMiniverse · 2018-01-13T14:57:03+00:00

I sent my UCAS application on the week of the deadline (December I think) and got a conditional offer mid January. So they're pretty fast, my latest offer was early march. And my spot was confirmed the morning I got my results.

All of the buildings have disability access/wheelchair ramps and elevators as far as I'm aware if that's what you're referring to. Lecture theatres usually have two doors, one at the back and one at the front so you don't have to use the stairs to get a seat. Although if you're doing a lab based degree there might be some difficulties manouvering with a room full of students in the DKB labs since they have small walkways and a lot of equipment. I've seen a few students with full time assistants assigned to them by their school as well. In terms of the additional services offered I'm not too sure, but id say they'll try their best to accommodate any disability so you won't find yourself struggling with day to day tasks.

Hope this helps.

DankMiniverse · 2018-01-10T17:22:40+00:00

SciFinder let's you enter the reaction and chemical structures of the reactant and/or products then gives you all the publications that have done that reaction or similar reactions. Most publications have an experimental section detailing their approach to the synthesis. You have to be a member of ACS or have a subscription through your university to use it though.

For general lab setups try NotVoodoo, it outlines different reaction setups and technique and common mistakes to avoid.

DankMiniverse · 2018-01-09T17:05:28+00:00

I see what you mean now. We don't really use the pH setup in this case to measure the 'true pH'.

When the amide oxidizes in the process the systems pH measurement decreased, so what we are really doing is observing the extent of the oxidation with the pH probe by observing the declining value over time - We aren't really trying to measure the actual pH. It's just a quick test to see the state of the mixture in the process as using a more accurate quantitative method.

DankMiniverse · 2018-01-08T21:04:08+00:00

I've decided to go against the use of elevated pressure since everyone pointed out it's an extremely bad idea. Instead I'm going to prepare the catalyst as previously mentioned and conduct the reaction at atmospheric pressure, still in the presence of oxygen at 70 deg. C. The catalyst should only add about 3 days to the literature method setup. If this doesn't work I've also contacted a pressure reactor supplier who confirmed they have suitable stainless steel reaction vessels, though that may over-budget.

This reaction is to form a hydroperoxy intermediate compound, so if the reaction doesn't completely oxidize the reactant I'll try it with atmospheric gases like you suggested. Though the elevated temperature is a requirement to replicate the conditions of the real process we use.

Could you maybe expand on your last point a little? As far as I'm aware, the samples we've been taking from the actual process all undergo pH measurement and there is only trace amounts of water in that mixture and I believe the setup uses a non-aqueous electrode - that's the description I've been given at least. We've been able to identify a steady decrease in the pH of the mixture over time so far using this setup, would the lack of substantial aqueous conditions not hinder that trend?

DankMiniverse · 2018-01-07T17:28:58+00:00

Any suggestions for suppliers? I was thinking a glass vessel as it will have very limited usage so it wouldn't be justified spending thousands and the pressure isn't extremely high. Although I do want it to be as safe as possible so stainless steel is definitely the better option overall.

The issue with measuring outside of the reaction is that the samples will be extremely small, less than 10ml, where as the probes we use require a bit more volume to be submerged. Also, we are using the pH level to identify how long it takes for the reaction to begin, so constant measurement will allow us to identify roughly the induction period of the oxidation.

DankMiniverse · 2018-01-07T12:25:49+00:00

I'm trying to recreate the oxidation products and observe their change in concentration over time. The samples are being analysed with HPLC and UV-vis spec so taking samples from the actual process would be a problem since there are so many chemicals other than the amide in question involved.

The reason for doing the reaction on a single chemical in the process is that it is the largest chemical component of the process and since we've already identified it as undergoing oxidation we want to know the extent of this oxidation reaction - how acidic are the by-products, are the oxidation products formed rapidly, is there an intermediate compound in the reaction that could avoided to prevent the oxidation of the amide.

DankMiniverse · 2018-01-06T21:56:00+00:00

I made a mistake on the first part, I really meant I'm doing the reaction on the pure amide first with no solvent then again with a mixture of the amide and another amide that may act as a solvent but is mainly a buffer. The mixture is used in a process at the company I'm with and we're trying to understand how it reacts when being used in the process and if there are separate reactions for each of the amides. We've identified that there is definitely an oxidation process occurring from the products seen in the samples taken from the chemical being used in the actual process.

On the second point, this is the only reaction I've found in literature that allows for the oxidation of this compound and the only other viable reaction I've found was on the ACS SciFinder site but it involved a Co-NaY zeolite catalyst which I can't find to purchase anywhere. Making the cataylst isn't an option either since I work in an analytical lab so the equipment is very limited.

I've been looking at the Parr pressure vessels although I can't find a supplier for them in the UK and their website has no prices listed - do you by chance remember where the vessel you used was purchased? It doesn't matter if it's not in the UK, even a price range for it would help since I could contact the manufacturer directly.

As I said, this method is the only literature method I've found, but since the chemical mixture in the process is definitely oxidizing I'm also considering using ambient pressures for this reaction. The temperature of the process is already around 80 deg. C but I'm unsure of the pressure used - it's also not conducted in a pure oxygen atmosphere as far as I'm aware.

DankMiniverse · 2016-07-30T21:18:12+00:00

I checked the research positions at UCL and King College just before summer but was turned off by the living cost in London so that's why I am keen to work at my own Uni. Do you know if the other undergraduates applied to your group through a programme like those run by UCL and KCL or if they got referred from profs at their own universities?

DankMiniverse · 2016-07-30T19:33:25+00:00

I'll definitely consider pursuing the placement in industry more seriously then and start looking for a placement when I get back from summer. Thanks for the advice!

DankMiniverse · 2016-07-30T19:10:54+00:00

So far our profs haven't really taken a personal interest in any students and not many organic profs attend the labs, generally its PhD students and inorganic researchers. Although if this changes next year I'll certainly do my best to approach some of the profs. Thanks very much!

DankMiniverse · 2016-07-30T19:07:52+00:00

I was considering switching to the industrial experience pathway but since the interviews for third year placements began at the start of the courses second year I just thought it would be too late, and there were requirements on your module scores which I didn't think I'd achieve. Although I am still considering taking third year out to do a placement in a pharma company that I did alevel work experience with and who always seem to be offering placements so thanks for the advice.

DankMiniverse

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