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hypervalent_iodine

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Everything posted by hypervalent_iodine

  1. Looks good to me. Although it should be noted that the tertiary alkyl halide won't undergo SN2.
  2. I would think that in the almost 9 years since this was posted, the OP will have either died from their stupidity, gotten over their explosive making hobby or learnt a few lessons and survived to tell the tale. Good advice nonetheless.
  3. Some reactions can be scaled up to gram scale and above and down to mg scale, but certainly not all. Typically it is much harder and more tedious to scale up rather than down and still retain good, if any yield. Asides from the added risks involved in increasing the amounts of various reagents, solvents, etc., larger scale reactions tend to suffer from an increased amount of byproduct formation due to issues involving mixing and heat transfer (there are others, I'm sure, but I'm not too familiar with them); these are things that aren't usually a problem when you're talking about mmol or mg scale reactions, but can be quite problematic when going up to gram scale and become even more of an issue when you move up to kg or industrial scale. It is often not simply a case of multiplying the amount of reagents and solvents you need when you are scaling up - you have to use common sense and generally you will need to re-optimise the conditions. Scaling down you can usually get away with using ratios to determine how much of each component you need to use with no detriment to the yield. The only real exception to that is in considering solvent quantities, since using extremely small amounts of solvent really isn't feasible. Increasing dilution is, however, something that can be easily overcome by altering other reaction conditions such as reaction time or temperature.
  4. Even assuming that it would work, you would run into a number of ethical issues that would most likely see it as a rather unfeasible exercise. And that's not to mention the extremely likely case of additonal environmental effects.
  5. The role of steroids is many and varied and don't necessarily equate to increasing bulk. Some have hormonal roles, other have more strucutral roles, such as cholesterol. I do not know if there is a plant sterol specifically implicated in promoting growth either upwards or outwards (these are two different processes in plants, IIRC), but if so then I would imagine that feeding plants suppliments of this steroid would not necessarily work since it would a.) need to be able to be easily absorbed by the plant with minimal chemical decomposition and b.) be only one part of what I can only assume is a complex network of biochemical pathways and therefore would likely require more than simply overloading the organism with one single compound. I'm not a biologist, however, so perhaps my assumptions are false.
  6. If you are doing an MSc you should, I would think, already be fairly familiar with journals in your area of research. Most people become familiar with them during their BSc, since a majority of courses are structured to incorporate and facilitate student learning through researching current literature. Not being well versed in computer science, I don't have any names for you, but a quick Google search should give you a fairly comprehensive list. Publishing papers is very much a 'unversity-centric' thing. I'm struggling to see how someone doing their masters isn't already aware or at least vaguely familiar with what publications encompass or have a vague inclination as to how they get published. The papers you publish are a culmination of your research and really, your supervisor is the person you should be talking to about it. Though I am not sure if it is the same for CS, most professors teaching science have their own research groups and if you were to do something under their supervision it would be within that group; essentially what you are suggesting is the same thing. The question of which journal you submit to really isn't one that can be answered here. It requires a good knowledge of your project, your results and a comparison of current literature, which is not something you can really expect members here to have. Speak to your supervisor. They will be able to tell you if you have enough for a paper or what you need to do to get there and where you should aim for publications. As for the process of submission, I myself am not familiar with all the intricacies. I begin preparing my first and (hopefully) second publication this year, so I've not had much of a chance to know how it all works just yet. Each journal will have its own formatting requirements, which are available through their website. They will also have guidelines for submission, which you can download (I think) for free. If you follow those in conjunction with whatever your supervisor suggests, you should be fine, although it's no guarantee you'll get published. It's not that obvious and it's often better to ask for clarification rather than making assumptions. As well, you could just as likely mean external or industry based scholarships.
  7. I think you'll find 'hydric acid' is added to or present in most anything you consume. Benzoic acid is something you find in food all the time. It's used as a food preservative. I'm not entirely sure why it is in there, though possibly it is one of the other antiseptic ingredients. The ethanol is needed in order to dissolve that as well as all the other antiseptic agents, which are, IIRC, terpenes and won't dissolve in water.
  8. I know what the mirror test is. I am asking you to further your points on how exactly you suppose you challenged it. It's hard to formulate an answer if you don't clarify your OP.
  9. Now for some real contribution. Exactly what do you mean by, 'challenged the mirror test'? Do you mean that you are challenging the premise of the mirror test? If so, could you perhaps elaborate?
  10. If you can buy the racemate, you could always just separate the enantiomers yourself. It would work out cheaper for you too, since buying enantiomerically pure substances is rather pricey, as a general rule.
  11. No. The idea that the Big Bang was an explosion is a misconception. Rapid expansion, not explosion.
  12. Have you been using Google web search or Google scholar? The former isn't going to get you much of anywhere in terms of finding a journal article. Use Web of Science, as ajb suggested, if possible. Otherwise, a Google scholar search should suffice.
  13. You need to show us what work you have done. Members here are not obliged to do people's homework or assignments for them, but many are more than willing to help point others in the right direction if they get stuck. You won't learn anything by people just telling you the answer.
  14. What you've said about transition metals are true, however the examples you give are not coordination complexes, they're hypervalent compounds. The concept of hypervalency was a matter of contention for a long time after the development of the Lewis-Langmuir theory of bonding, which considers the covalent bonding between two atoms as a 2-centre 2-electron model - i.e. it is concerned with two atoms (the centres), which share a bond consisting of two electrons. Hypervalent compounds such as the ones you've listed and many others used to be considered as merely the 'exception to the rule' following Lewis' seminal work and as a result, not much was done to study them until the 1940's and onwards. In the 1950's, hypervalent compounds were found to adopt what is known as the 3 centre-4 electron bonding archetype. The 3c-4e model initially arose from a qualitative application of molecular orbital theory, which describes the linear combination of one p-orbital from a central atom and two ligand p-orbitals to generate three molecular orbitals. It looks like this: (picture copied from my own research proposal) In contrast to the localised two-electron bonds (i.e. a localised sigma or pi bond) described by Lewis and Langmuir, in which there are two molecular orbitals (the antibonding and bonding molecular orbitals; or AMO and BMO, respectively), a 3c-4e bond combines to give three molecular orbitals - a bonding molecular orbital, a non-bonding molecular orbital (NBMO; the HOMO), which contains a node at the central atom, and an antibonding orbital (the LUMO). This model has since been supported by various computational models and is currently a generally accepted archetype for hypervalent bonding. Anyway, this isn't stuff that you ever need to worry about in undergraduate, since it isn't really taught outside of 'some compounds contain central atoms which have a valency exceeding 8'. Nevertheless, I find it interesting, so I thought I'd share.
  15. A few things: - Are the NMR spectra you put up there of the one compound and is this meant to be the spectra for your final compound? - Do you have any 13C or mass spec or any other characterization data? - Why are there no peak integrations? The NMR you have up there is pretty useless without integrations. You might be able to tell various functional groups, the peak at 10 ppm in particular is a dead give away, but you're not going to be able to definitively say what you have without some form of integration. The only other thing you can do is ask yourself what kind of product you know you should have, given the reaction. Regarding how your practical went: how high is high? Did you notice any changes at all? Sounds to me like you isolated the wrong bit and you're trying to melt a salt of some kind.
  16. Phi! What happened to our non-disclosure agreement? If nothing else, I guess this means I'll be releasing a commemorative Phi for All 2012 Mayan fashion DVD sometime in the near future. Victoria's Secret, move on over. Is it too late to request that I get to do the April shoot? I can do all sorts of amazing things with chocolate. I guess you or moo could play with my the parts of the Easter Bunny.
  17. This isn't really chemistry related, so I'm moving it somewhere else. Patents are freely available. I don't know about Carmex, but it sounds more likely to be a trade secret than a patent if the formula is not available. My understanding of patents is that the holder of the patent is granted the right to exclude others from making, using, selling, etc. the patented invention for so long as the patent lasts. Therefore, if the formula for Carmex is a patented invention, you would not be able to do any of those things without their express permission. Trade secrets differ in that the information is shared only to a small subset of people (employees, etc.) and is done so under a non-disclosure agreement. If you can reverse engineer a product to discover a trade secret, then you are within the law and you can use the information, so far as I know.
  18. Sugar dissolves quite well in water and interacts with it via a network of hydrogen bonding.
  19. Come, now. We Brisbane-ites have access to all sorts of historical sites. Like, erm..city hall, where they recently dug up old and apparently interesting bits of discarded rubbish from last century.
  20. The are 6 coordinate bonds. Might be a touch hard for it to adopt trigonal bipyrimidal or square pyrimidal geometry given that both of those molecular geometries contain 5 ligand bonds.
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