hypervalent_iodine

I repeat: And this thread is staying exactly where it is, which happens to be exactly where it belongs.

DOOM-N-GLOOM and his sock puppet, Centrifugal Force, are both banned. In future, if you're going to use multiple accounts to give someone rep points AND get away with it, maybe don't make it so obvious. Edit: after some discussion, DOOM-N-GLOOM is now allowed back.

There's no way for you to do this accurately. "Drops" are by no means a standard unit of measure, so you'll first have to come to some conclusion as to how many mL there are per drop. After that, well, this is homework so I'm not giving you the answer. What do you think you need to do? Ask yourself what has happened when the solution has a neutral pH and what that might mean in terms of solubility. (Sorry this took a while for me to reply to.)

! Moderator Note Or you can come down of your high horse and listen to what staff tell you to do. As it happens, personal attacks are also against our rules, so I would advise against that in future. You are required as per our rules to provide a testable model, back your hypothesis up with evidence (note: not more baseless speculation) and detail what predictions it makes. If you can't do this, your thread will be closed, you'll quite possibly end up suspended and you'll not be allowed to bring up your topic again. Suit yourself as to which way you go, but don't say you weren't warned. Do not continue to derail this thread by responding to mod notes.

! Moderator Note Moved to Speculations since this is just promotion of your own hypothesis. Also: Please start calling people by their actual user name.

! Moderator Note bulla, stop with the thread hijacking. Anymore nonsensical and irrelevant posts are just going to be deleted.

Because plants are terribly complicated and I cant imagine that coating the flue of a coal plant with some sort of synthetic leaf would be in sturdy enough to be viable. It would be dead before you could capture anything.

! Moderator Note Moved to Lounge.

! Moderator Note charles brough, One thread per topic. Thread closed.

Okay, to bulla and Mosheh: Read the title of this thread. It is not about whether carbon sequestration is good or bad and it is not about climate change. It is about the use of metal organic frameworks as a technology for carbon sequestration in industrial plants. Whether you like it or not, industrial plants exist and will continue to exist into the foreseeable future. I find it absurd that anyone would think that a commercially and environmentally viable way to make industrial output cleaner is not a good idea - but this is not the thread for that argument. Also, Mosheh, you seem to be confusing sequestration with storage.

bulla, most of that has absolutely nothing to do with this thread, so I'm going to ignore it. How is cutting down CO2 emissions not environmentally sustainable? The whole point is that it is environmentally sustainable, so I'm rather confused by that comment.

! Moderator Note bulla, Firstly, Newton? This thread is about SR - keep it that way. Secondly, if you're going to post off-topic speculative material in someone's thread, at least make it readable.

My first bit if help is to to advise you do your assignments earlier than the day they're due. Your GPA will thank you. I'll look at the question when I get home, but for now I'm moving this to homework.

! Moderator Note iNow, you need to choose your thread titles better or at least give a bit more of an OP so as not to give the appearance of deliberately antagonising theists. If this thread starts turning sour, it will be closed without hesitation. The flaming often found in the Religion forum needs to stop, so everyone can take this as a preemtive warning to choose your words wisely.

Who said we need to get rid of the trees? Keep them there and let them continue to take up CO2. I agree that the land thing is an issue. I'd be interested in seeing numbers regarding how many fully matured trees you'd need to effectively neutralise emissions from an industrial plant. I'd say it would be rather large, although considering that current methods don't remove anywhere close to all CO2, you'd really only need a fraction of that number for it to be an improvement. The time factor can be overcome by using a fast growing species like pine. I'm not sure how MOFs would respond to H2S or SO2. I'm not sure how prevalent either of those are in flue gas so perhaps they won't be so much of an issue. How does the current system tolerate them (and the rest of the mess you mentioned)? As for the heating issue - I'm not really sure. I think it was mentioned in the seminar, but I don't seem to have written it down. I might look into it when I get back into Brisbane and have a better connection.

! Moderator Note owl, don't even think about keeping this line of conversation going. You've been warned multiple times about doing this - any more and it's suspension time.

! Moderator Note Mosheh Thezion, thread hijacking is not permitted here or in the main science forums.

I should also add to my above reply to Xitten that the overall selectivity of such a system is also generated by sterically inhibiting the potential for physisorption. mississippi: I'm glad you brought this up. The difference in energy requirement between the current technology and this example is noticeable, but as an old professor of mine pointed out, small enough that the difference could easily be made up on a warm summer's day. I forget what the numbers were exactly. The proposed solution is to pump it underground, use it to push up oil and then store it there. As I said in the OP, it seems a rather tenuous and risky thing to do, yet I am told it is in full operation in some parts of the world. Oh yes, the chemistry is wonderful. As I said to Xitten, I'm not knocking MOF's as a whole, just their use in CO2 sequestration. The solution they came up with is certainly eloquent and it is an improvement on what we currently use, but then so are trees. I suspect that scaling up may also be an issue, even if you ignore the obvious cost efficiency factor. think if you look up D'Alessandro's name, you may find some other papers by her in the area of MOF's as conductors (Edit: I found this one). The first half of her seminar last year was all about that aspect of her research, though to be honest I only listened enough to take a few notes and I don't recall if what she presented had been published. Looking at my notes, the body of it seems to be focused around the incorporation of a redox active paddlewheel shaped ligand - (O2CMe4)(THF)2 - onto a switchable RuII, III frame (reminds me of Prussian blue) to generate an interpenetrated BCC structure that has low porosity and is thermally stable up to 500oC. Doesn't look like her group has managed to utilise this in any prototypes, but progress is progress. I found this paper, which looks like a nice review of the possible applications for MOF's. I might add more about this when I have had a chance to read it.

It's to do with the way it's sequestered. The reaction itself is a rather simple one (the formation of a zwitterionic carbamate in this case) and it is inherently selective. The reaction is reversible and within this particular context, is reversed by using simple temperature swings. So, by tethering a secondary or primary amine to their framework, they create a functionally dense, solid support with many available sites for reaction. In the paper I linked, they found that ~ 82% of the reactive sites had reacted with CO2 with minimal uptake of N2 from the binary mixture (close to 0 mmol/gram, in fact), which is a pretty decent result.

The rest of your quote, in which you stated: No, no, no. why do you insist mixing the diagrams, it is getting awesome. please re-read my explanations about the difference between the 2 diagrams. I get the feeling you don't want to understand. Which is what Iggy replied to, holds the same meaning with or without the entirety of post #204. The issue is moot, so please move on.

The issue then is the energy required to maintain them and the space required to house the systems, etc. I think there has been some efforts in that area, but I don't now how successful or how viable it is. I kind of like the idea of algae as biofuel feedstocks, but that's another story. Ah, yes, but you'll notice I stated that I found it pointless within this context. Of course it's not a waste of research, I just think that focusing it towards this particular application is a waste. There was mention of using MOF's as drug delivery systems as well as for other biomedical applications. The presentation I attended also went into research where they investigated their use as conductors by incorporating redox active ligands into a ruthenium based framework.

Those pesky cobalt dimers, wrecking our atmosphere.

I've not had terribly much experience with polarimetry (yet), but I am quite sure there would be a number of books on the subject that would meet to your satisfaction. Where you look would really depend on how much depth you want to go and what sort of questions you're trying to answer. A good organic chemistry text book would give as much of an overview as an organic chemist needs to really know; beyond that you may be better looking into phys chem texts (not that I've ever read one). One book you may be interested in looking up is called 'Stereochemistry of Organic Compounds', by Eliel and Wilen. It's an excellent book that goes into a great deal of depth about all manner of things (I would say that your library should have a copy). During my honours year, it was the only book that gave me any kind of explanation for a particular concept I had to present on not written in French (Horeau's method, if you're curious and feeling particularly sadistic). The relationship you mentioned between wavelength and the magnitude of optical rotation looks to be a non-linear one and gives rise to something called optical rotatory dispersion. The wiki article I just linked you states that this is used to make conclusions about the absolute configuration of inorganic substrates. For organic compounds, altering the wavelength isn't really something I've seen employed and the reason for that would obviously be one of consistency. Usually 589nm wavelengths are employed, which is denoted by D in [[math]\alpha[/math]]D. As for Fischer and co's work from the 19 and 20th century - I agree that it's pretty incredible and I've mentioned somewhere here before that I consider them to be some of the greatest organic chemists to date for their ingenuity. You should, however, be careful not to confuse relative stereochemistry with absolute stereochemistry. They were able to chemically deduce the relative stereochemistry of each of the simple sugars by building off of observations made using glyceraldehyde and working their way up in chain length. In truth, the fact that they correctly assigned the absolute stereochemical configurations of all of the simple sugars was really just pot luck.

The concept of carbon capture and storage is something most people are aware of. It refers to a technology used to address problem of CO2 emissions by some the world's largest offenders - namely the fossil fuel industry - by sequestering and storing large amounts of the gas. Over the years, many methods have been developed to help achieve this, all with varying degrees of success, as per the below flow chart: [From here] I'd like the focus of this thread to only be on one of these, specifically metal organic frameworks (MOF's). For those who do not know what these are, the wiki article on them is fairly informative. The major issues in developing a way to capture CO2 from industrial exhausts is in being able to create something that is scalable, cost effective and of course, something that works. Typically, they operate in one of three modes: pre-combustion, oxy-fuel combustion or post-combustion. For the sake of brevity I'll only be talking about post-combustion methods, which involves the segregation of CO2 from flue gas, the composition of which (for brown coal) is as follows: 74% N2, 14.3% CO2, 7.7% H2O, 3% O2 and trace amounts of other gases. Using current technology, which is based off a patent from the 1930's, achieving separation of CO2 from flue gas increases the power requirement of a brown coal plant by 40%. It works by utilsing an aqueous solution of alcoholic amines (typically 30% w/w) to sequester CO2 by a process of chemisorption - i.e. by reacting the amines with CO2 to generate the corresponding carbamates - followed by a process of chemical desorption to regenerate the amines. This is where MOF's come in. Currently, MOF's used in post-combustion sequestration are effected either by physisorption or more recently, chemisorption. The latter certainly reduces the energy required to regenerate the solid material as opposed to the aqueous amines, however they are not particularly selective and have low capacity. Chemisorption of CO2 using MOF's overcomes many of the issues with physisorption and is very similar to the current method used - it aims to adopt a process of chemisorption (generating carbamates by reaction with an amine) to separate the CO2 followed by desorption. There has been some work done in this area over the past few years (see here), however I will only use one very recent example in this thread, which comes from a collaborative effort by the University of Sydney, Berkley and the Van't Hoff Institute for Molecular Sciences: McDonald, T. M.; D'Alessandro, D. M.; Krishna, R.; Long, J. R., Chem. Sci., 2011, 2, 2022 - 2028. Their idea looks like this: [image from their paper, referenced above; BTTri = 1,3,5-tri(1H-1,2,3-triazol-4-yl)benzene; mmen = N,N'-dimethylethylenediamine] Rather than using alcoholic amines, this work utilises the secondary alkylamine, N,N'-dimethylethylenediamine (mmen) and since MOF's work in solid phase, the need for solvent is abolished. I won't go too much into the paper, except to say that it shows a great deal of promise in selectively taking up CO2 - in fact, it's been shown to work above and beyond any other MOF to date (for binary mixtures, at least). My own personal opinion of the technology is that it comes across a bit of a waste of time (within this context, at least). To my mind, the problems surrounding CO2 capture and storage and solutions thereto seem so obvious that I'm wondering if perhaps I'm just missing something. I know I'm not the only person who thinks this - one of the authors of the above paper gave a seminar last year at my university and the queries I'm raising here are in fact the same as those brought up by professors in the audience. Primarily, it boils down to two questions: This technology does not 'do away with' the gas, it simply captures it. The solution to 'what do we do with all of this gas' was presented by D'Allesandrio in a seminar I attended last year. She stated that current methods involved storing it underground and using it to push up oil to the surface; indeed, there are already facilities around the world that do this. This to me seems a little silly, since I can't see how you would keep it where you put it and because it seems like there would or should be a plethora of safety concerns to go with it. Does this method of storage actually work and are there in fact any imminent safety issues surrounding its use?* Perhaps most importantly, what I am failing to understand is why we would waste time and money developing and implementing this technology for CO2 sequestration and storage, when planting trees could do the same thing more efficiently? As far as I am aware, there are some places that are trying to solve the issue by planting trees around industrial plants (I'm not sure where this is being done, it is really a vague recollection) - is this not a ubiquitously viable option? *It's worth noting that by D'Alessandro's own admission, the safety of this set up has not been fully investigated. It's curious then, that this is in operation in other parts of the globe. Here in Australia we have one storage plant, situated in Otway, which is operational but only being used for testing as of last year.

Or even further down the line than that. The other way is if two black parents gave birth to an albino child or if one of them had some as yet undefined genetic mutation. IIRC, there is at least case where this has happened, although the reasons were unclear.