hypervalent_iodine

I suppose you could make the solution weakly basic. This should push the equilibrium towards forming the bicarbonate ion, which then equilibrates with carbonic acid. A better way to make NaOH would be to combine Na2CO3 and Ca(OH)2. I mean, it's not a particularly useful reaction for a kitchen set up because you need temperatures of about 825oC to get CaCO3 to precipitate (you'd essentially need a kiln or something similar). Careful though. If you actually intend on making NaOH, you should read the appropriate MSDS's and take proper safety precautions (wear decent personal protective equipment, etc.). What is this for?

The positive charge would lie on the magnesium. MgBr+ is simply a magnesium bromide ion. This species doesn't have much of anything to do with the actual Grignard reaction though. At the end of a Grignard reaction you get Mg(OH)Br, which then goes on to react with the acid you'd have in solution to form water, bromide ions and Mg2+. Have a read of this, it might help.

Couldn't agree more. I actually found it very useful when I was doing sugar chemistry and I was trying to find where my ridiculously small ring bound H peaks were. Damn things were near impossible to see. It also gave me very accurate peak predictions for the aromatic functionalities on my protecting groups. It's useful for the stuff you might encounter in undergraduate as well. But yes, in terms of predicting long-range affects, etc. it could be better.

I have not always had this experience with people who have approached me in the streets or at my home. In fact I once had a young man approach me at a bus stop who, after the initial, 'hello', etc., asked me if I believed in God and if I'd ever heard much about his religion (he was Mormon, from memory). When I answered no, rather than be offended he commented on the chemistry homework I had been doing while I waited for my bus. We ended up having a good 10 - 15 minute discussion about organic chemistry and science in general, with no reference to religion or God at all. That particular group of missionaries were ethically upstanding in the sense that they by no means intended to enforce opinions and beliefs onto people who clearly had no interest. Their job was to discuss religion with people who had a common interest or people who simply were wanting to learn more. When it becomes 'wrong' is when a group of people or a person tries to push their system of beliefs onto people who do not want it. Religious discussion and debate does not necessarily fall into this category, since both parties are willing participants. As a comparative analogy, I once came across a man who insisted on handing out leaflets to everyone he came across at a bus stop (it's where they always manage to find me). This in itself is fine. I didn't see the point in potentially engaging in an argument over a piece of paper that I was not obligated to read and so I took it. A few seconds later, after I had sat down, the same man asked to come and sit with me. I sighed internally, knowing where the situation was headed but politely agreed. Sure enough, the 'do you believe in God?' question came up. The difference came when I said no and said gentleman started off on a rant about how Darwin was wrong about evolution because (apparently) there are no fossil records to prove his theory. Again, that is not immoral, just somewhat annoying. I then told him that I did not wish to engage in a debate about religion and asked if he could kindly leave, to which he replied by pausing, laughing and then continuing in his attempt to tell me that God is real and that science is wrong. That is where the situation became, in my opinion, unethical - when he continued to force his point after I clearly stated I had no interest in hearing it.

Yes, I should have added a to the end of my post.

The brackets are there by manner of convention. As you have written it, you can remove the brackets and it won't change anything. Remember you also have to multiply the coefficients.

Had a brief look at this. It's really not complete at all in terms of a reference site. The organic reactions you chose to exemplify (which are few, to say the least) are obscure for tuition at undergraduate level, with one or two notable exceptions. Your inorganic section is also quite lacking. The document on IUPAC nomenclature is good if all you ever deal with is alkyl chains, but this is not the case for college/university level course work. The only thing I found that was even slightly thorough in its content was your document on analytical chemistry and also the phys chem documents. That being said, I didn't read the whole thing, so maybe I am wrong. In any case, this is a thread about organic chemistry reference sites and to be brutally honest, the one you linked was not one I'd recommend for organic chemistry. I was in fact tempted to report this as advertising spam, but I decided to leave it given the nature of the thread.

The tone of his post made me suspicious that he hadn't read enough papers to become particularly familiar with how to present his topic, hence my suggestion. Certainly, he should have read extensively during the course of his research - as to whether he paid attention to the layout, etc. is another question altogether. I have to question how rigorous your research has been? No harm intended, but as ajb mentioned you should have done some pretty thorough background reading if you intend on publishing a new theory (or even an extension to an existing theory). Potentially, what you have discovered has in fact already been addressed by other people or groups who are doing (or have done) research in the area. As do I. Or more, I can never work out how to start things. It usually takes me until I've written the first paragraph before things start to flow in any sort of direction. One of the best things I've found to do is once you've written the first draft, leave it for a day or two and then read back over it. I am always surprised at the number of things I end up changing or fixing when I come back to it.

I don't know how to not write in double negatives too.

I was really just giving an example there. Thanks though. There is definitely a good reason why I never did inorganic after I finished undergrad .

Not so much in first year undergrad, which was where I was referencing my analogy from. Anyway, I know that, but there's a difference between researching content and analysing the way a paper has been written.

If you're stuck on how to write a paper the best thing that I find to do is to go out and read a bunch of papers in a similar vein to your research and work from there. I did that a lot when I was in undergrad and I was asked to write journal style articles with no clue as to how to set it out. As has been mentioned, most journals have set guidelines about article presentation and exact formatting, so you will most likely have to modify it somewhat. Still, it's good to get an idea of how people who have been published go about writing their reports, particularly if you've never done it before.

Okay, so there is a reason why (in Australia at least) there are specialised labs that handle HF. As a home operation, this is a very silly idea and I'm glad you're not planning to attempt it. In terms of the reaction, it depends on what sort of ligands are attached to the Al as to whether the hydroxides will be able to substitute them. AlCl3 would work. In industry, the production of Al(OH)3 is achieved using the Bayer process, which requires high temperatures and pressures. Another alternative be to use a sulphide, Al2S3, and react it with water. Problem is that you get SH2 as one of the products, which is particularly nasty stuff. Turning the Al(OH)3 into the sodium salt also wouldn't work. You'd actually form the tetroxide, [Al(OH)4]- Na+. To make cryolite, it would be much easier to combine an AlF3 with some sort of sodium salt solution. It can be done at reasonable temperatures and doesn't require HF. There is a problem in that trifluorides have a characteristically poor solubility in most solvents and there is also an issue of safety (very toxic when it comes into contact with your skin). The problem with your proposed reaction to cryolite (other than the HF thing) is that you may not end up with the hexafluoride. Ligand substitution is a stepwise process, by which I mean one ligand is replaced and then another (it doesn't happen all at once). With each successive substitution there are less reactive positions for the fluoride ion to attack, so statistically speaking the second, third, and fourth (etc.) substitution becomes progressively less likely to occur. This trend is supported by Gibbs free calculations as well (using ΔrG°= -RT ln Kf). With each substitution comes a new formation constant, Kf. When we get to the second substitution, the value for Kf decreases, which correlates to a smaller ΔrG° and thus indicates that it is energetically less likely to occur spontaneously. So I guess what I am trying to say is that you are better off not relying on 6 successive substitutions, because (at a guess) there is a chance you'd only end up with a tetrafluoride and two remaining hydroxyls in the trans position, or something to that affect. I could be wrong on that last bit though. In any case, HF is not something you want to use if you can avoid it.

The concept of 'real men', Capn, does not include gingers. Back to underwater basket weaving you go.

Based on your previous threads I have to ask you, what is this for? Anyway, this is from wikipedia (in future, you should try research your questions yourself. Questions like these a relatively simple to get answers to using Google).: In terms of equipment, you need basic glassware such as Erlenmeyer flasks, a hot plate, access to well ventilated areas, personal protective gear (goggles, etc.). If this is a home set up, I wouldn't recommend going for the anhydrous stuff. Dioxane can be pretty nasty if you somehow ingest it as well, so please be careful. Also, hydrogen sulphide smells awful (it's responsible for the smell of rotten eggs) and is very toxic. Also, it is explosive when in contact with air. So really, just don't do this at all if this is a home set up.

Yeah, I suspect either that or something similar would be the case. It is definitely a case of steric interference anyway - enzymes are good like that.

Are you sure these will dissolve? Do you have references for that? As Mr Skeptic said, being unsaturated will not make them any more or less polar. It is still a hydrophobic alkyl chain with a hydrophilic carboxylate on on end. I am not at all surprised that your emulsion is coalescing and/or creaming with an alkyl chain that massive. Carboxylic acids any larger than about 5 carbon long tend to be poorly soluble. Are you using any surfactants? By the sounds of it, you have very little chance of this succeeding without them. Also, adding a fatty acid to a basic solution will turn it into a carboxylate, which is RCOO- not RCOOH. Also, you wouldn't be saponifying in the traditional sense, since base catalysed saponification is the reaction of an ester with a strong base to produce the acid and the alcohol. You already have the acid, so there's no point. What you're suggesting is simply shifting the deprotonation equilibrium of the acid towards the products side by increasing the pH (sodium hydroxide is fine for this). Still though, when you convert back to the acid you'll probably be left with the same problem of coalescing/creaming. If you aren't, well then the reaction is still pretty pointless because sonicating it will achieve the same thing with less chemical wastage.

Regarding the cyclopropane and whether or not it may be isolated, the short answer (as per my supervisor) is not often, as I had suspected.

In chemistry, if these sorts if things (equipment and program suites, etc.) are usually mentioned in the experimental section under the subheading 'general methods' (or something similar). It doesn't need to be detailed, just a simple, 'this was used to do this'. This is an example from an assignment I did in undergrad:

Vectors for what, exactly?

I can't really see how it is the professor's fault that you failed to understand a paper that you were meant to research into yourself. You were given a task that involved using your ability to research and present on a topic that required critical thinking - just because your professor had data that neatly explained every little detail for you doesn't mean he should be obliged to provide it. In a way it actually spoils the point of the assignment. Whether or not he helped other students as you say is, in my opinion, irrelevant. It might not be fair from an egalitarian point of view, but it is hardly the point. The fact is that you were given a paper, told to research its contents and do a presentation on it - not your professor. As I mentioned in an earlier thread, when it comes to your work, your university experience and the people you come into contact with at your university all I have seen you do is complain about each for one reason or another. Honestly, if you are that unhappy about where you are and what you are doing, perhaps it is time to consider going somewhere else. Either that, or maybe you should start to think about whether the issue is in fact with the university, etc. or if it is with you. Just a thought (no maliciousness intended).

Hmm, that is interesting. I had thought maybe that could be the case after I had posted and remembered that a lot of research groups that operate in the same building as I am use heterogenous colorectal cancer cells lines all the time for Caco-2 assays. They can be a bit touchy sometimes, but are mostly easy to deal with and grow in vitro.

Okay, here is the retrosynthesis from the paper: And here are the yields and ee's for a few model dienes: As you can see, there are some pretty good ee's in there on a the dienes they looked at. Looking at previous papers, I can say only speculate whether the cyclopropane 'intermediate' can be isolated (I might actually email my supervisor to ask him if he knows). There were previous studies performed by the other group working with Williams on the project (Davies group) in the lead up to the completed synthesis of vibsanin that managed to isolate similar cyclopropanes. The Cope rearrangement seen in the formation of the cycloheptadiene systems occurs when the reaction vessel is allowed to warm to room temperature. The cyclopropane then adopts a boat conformation, which is what allows for the good stereoselectivity, and undergoes the rearrangement. So I suppose it is possible, but the spontaneity of the Cope rearrangement even at RT suggests to me that it would be difficult. There are two papers in particular that deal with the topic of the cyclopropanation: http://pubs.acs.org/doi/abs/10.1021/ja974201n http://www-scopus-com/record/display.url?eid=2-s2.0-0027488634&origin=inward&txGid=Hzq14-vMO3yYPrAMd-H-ylv%3a2

All I can really comment on is that the sulphur you find in foods and the sulphur that is mined, etc. consist of different sulphur-containing compounds. In other words, the sulphur atom is the same throughout, but the molecule that they are a part of may be different. Allotropes simply refer to the way by which atoms connect to one another in a crystal structure. For instance, diamond and graphite are both made up of carbon, but the carbon atoms are joined to each other differently, resulting in different physical and chemical properties. Isotopes are where you have different 'types' of a particular atom (i.e. same number of protons in the nucleus, but different number of neutrons). There are only four isotopes of sulphur that you see in any real abundance, the rest are quite radioactive (with the exception of one of them, whose half life is 87 days). The only thing that would be different between the sulphurs in each of the various molecules is perhaps the oxidation state, which describes the hypothetical charge of an atom if all of the bonds to said atom were ionic (loosely, that means that the electrons within the bond are localised solely on one of the atoms and not the other [electrons are negatively charged]). I am not too familiar with the rest of it, sorry. Hope that helps.

As far as I know, cloning human cells is a very long and difficult process. It is much easier to simply extract them from a source such as embryos than it is to clone them. I should think that even if you only took one extract from an embryo and cloned it for further use, you would still run into the same ethical boundaries. Also, there would still be a requirement (I think) to use embryonic stem cells as a base reservoir.