Horza2002

Curly arrows are one of the corner stones of organic chemistry (along with tetravalent carbons and a few other little gems). The curly arrows, will are talking about orbital overlap, don;t require you to know about the orbtial overlap (for a basic understanding anyway). If you have already worked out where the delta negative is and where the delta positive is, then all you need to do is put an arrow between the two and your sorted. Curly arrows are normally only reserved for organic mechanisms since metal ions are a little more tricky and often to react in that way. That Is exactly the reason we have all recommended that you learn the basics of using curly arrows so you don't have to memorises thirty mechanisms (and beleive me, by the end of your degree when you've had close to 100 mechanism to study, you won't be able to memorise them). Once you understand the basics of how to use curly arrows, you'll see that most of the mechanisms are very similar anyway.

Not to worry, once you've found out it'l be much easier to try and suggest something that might work before trying to use acetic anhydride. In the lab, when trying to acetlyate something, we either use acetyl chloride (which is even more reactive than acetic anhydride) or acetic acid with a coupling agent (like DCC, EDCI); see links below. But again that depends on what your trying to do. Im not sure this is going to work at all....its just an idea that might work; at that high a temperature everything will be a gas and I have no experience with gaseous reactions. You said that you'd found somewhere else that heating to that high a temperature could work and then I suggested adding a dessicant to make sure that any water that is relased or contaminated won't destroy your product again. Seeing as this reaction will be energetically unfavourable, it might take a while even at such a high temperature and being a gaseous reactiong will also slow it down. Acetly chloride: http://en.wikipedia.org/wiki/Acetyl_chloride EDCI: http://en.wikipedia.org/wiki/1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide DCC: http://en.wikipedia.org/wiki/N,N%27-Dicyclohexylcarbodiimide

Thinking about it, I agree with the police officer being shot stance is a little extreme case. But with the fire fighters, I here a lot about people either dieing or being seriously injured while on call fighting fires. Although my opinion is definately biased as I know people who are fire fighters and a friend died from injuries he sustained getting a lady out of a burning building. I personally consider him a hero..

Techincally acetate is a special type of acetyl. Ive attacked a file that shows the difference between the two for you. Basically, acetyl refers to CH3CO group whereas acetate is CH3C(O)O as well. Do you know specifically which functional groups you want to acetlyate? That would let me be able to tell you if acetic acid itself would be good enough. A dessicant is a molecule that absorbs water into its structure...in the lab, we normally use calcium dichloride (CaCl2) or heated copper sulphate (CuSO4). You need to heat the copper sulphate because it often has several water molecules asscoiated with it and can prevent it from taking any further water from your sample. I've just had a quick look, copper sulphate melts at 200oC so won't be much use...however anhydrous calcium chloride melts at 770oC so that might work. Mhmm...in the lab, we have specialised glass tubes (about 8mm think all the way round and not sure wht type of glass) that can have a lid screwed down when we heat samples under pressure. One of these could be used...i guess you'll know more than me if borosilicate glass would survive being heated to that temperature and under a high pressure. I must stress, but I'm sure you already know, but having anything that high temperature will be very dangerous, especially an acid. So take care...especially your eyes. And theres nothign wrong with needing things explained slowly...took me a long time to learn the knowledge that I have now and Im sure I would need things explained to me slowly in your area of expertise. Doc1.pdf

If you were to heat it acetic acid to 800 degrees, you'd have to do it in a sealed enviroment otherwise your acetic anhydride produces would simply evapurate off (it boils at around 140oc)...although that could be way to purifity it...distill it off as any water will come off first...either that or add as dessicant to your glacial acetic acid as you heat it up. The problem is your trying to make something that is less stable than its starting material so is is very difficult to do wiithout specialiast equipment. If you just want to form some acetates, just using acetic acid itself works...thats how I do it in the lab.

I would say they are classed as heros because, while thre job might not be the most dangerous around, they are more relevant to everyone. Probaly one of the most dangerous jobs around is being a lumberjack. However, not everyone would have a service of a lumberjack (and even if they did, they might not know they have used one). While, all the time, you hear reports about fireofficer being killed while trying to save a building or a policeofficer shot for doing their job. SO it might be a media thing, but more importantly I think its because everyone sees them around and are relevant to far more people. And firemen regulally risk their lives to save others...whether it entering a burning builidng to drag someone out or cutting someone out of a car that has crashed with petrol is leaking around. Not to mention, that driving at relatively high speeds to get to the scene fast is also putting themselves at risk to try and save someone who quiet probably was doing something stupid.

There is a reason why Big Brother watches those who want acetic anhydride...?

Ok, I'll try keep this simple. Basically what it means, is that you are moving a carbon atom around between molecules. One specific example is the role of folate (also known as folic acid) is in the methylation of homocysteine using Vitamin B12; look at the file I've attached. Vitamin B12 is a cofactor required for the correct function of the enzyme methionine synthase. The His ligand on the bottom axial position of the cobalt and anchors it to the enzyme. Basically, the folate brings a new methyl group to the Vitamin B12 system so that it can continue on its catalytic cycle transfering it to homocysteine to generate methionine. The Co(I) species has a lone pair of electrons which then acts as a nucleophile to remove the methyl group from Me-folate. This leaves folate without the methyl group (the red section in the file). Once this has happened, the Co(III) activates the methyl group to attack by the sulphur of homocycteine. In terms of your title, it means transferring a methyl group from the folate to another molecule. Folate is also resoponsible for regenerating S-Adenosyl methionine once it has transfered the methyl group to another molecule in essentially the same manor as I have shown in the file. So in anwser to your question, it means moving a carbon atom from one molecule to another. Folate.pdf

It is proably closer to physics than chemsitry...although the ability of each material to faciliate heat transfer will depend on their chemical strucutre. Firstly though, as this seems very much like homework help, what do you tink causes heat retention?

Do you remove the layer of aluminium oxde from the cans before you started? When exposed to air aluminium reacts almost instaneously to gerneate a very thin layer of aluminum oxide. Accoridng to Wiki, sodium aluminate is prepared by reacting aluminium hydroxide with sodium hydroxide: http://en.wikipedia.org/wiki/Sodium_aluminate Aluminium hydroxide is a white/pale grey solid.

Good recruitment speach ther hyper

The triplet, doublet and quartet are not in exact ratio for an effect known as roofing. It is possible that its two signals overlapping, but if your a new learning this area, then it seems a little mean. What Uni are you at what undergrad year? Once the anwser revleaed to you, it will probably make perfect sence.

Typically, quaternary carbons (those that have no hydrogens bound to it) have a very low intenisty peak in the carbon NMR. Typically, they would be about 1/5 the size of the peaks you currently have in the spectra. However, if these are computer generated spectra, it might not give a proper approximation. The H-NMR does seem to imply that it is indeed 3,3-dichloro-2-methlypentane so I'm thinking that is what it is. thb, I can't think of what else it could be because you only have four carbon enviroments and five hydrogen enviroments (thus it implies there are 5 carbons one of which doesnt have any hydrogens bound to it). No COSY, HMBC, MHQC and PENDANT are different types of NMR experiments, that are 2D. For example, COSY tells you which protons are coupled to each other, HMBC tells you which protons are bound to which carbon atoms. PENDANT also tells you how many hydrogens are bound to each of the carbon atoms...so it makes it soooo much easier. http://en.wikipedia.org/wiki/Correlation_spectroscopy

It is difficult to predict the temperature a reaction rises too. I know its used to weld railway lines together and so is above the melying point of iron.

No I said that your C-NMR doesnt show a quaternary carbon in it. SO that seems to imply thats what it is. You are right that C3 is quaternary but I was saying that the NMR spectra implies that there no quaternaries. In 3,3-dichloro-2-methylpentane, look at the file Ive attatched: C1 - doublet C2 - heptet C3 - quaternary C4 - quartet C5 - triplet Im starting to wonder if this is a predicted NMR and so the C-NMR is hiding the quaternary NMR. I didn't say anything about any software...what did u mean? Doc16.pdf

http://www.gizmag.com/color-changing-plants-detect-pollutants-and-explosives/17915/ I was reading this article about research groups trying to engineer plants so that they change colour is they detect explosives or high levels in the air. At the end of the article they outline the aim to have them in places like airports so that the authorities can detect explosives in the air. To me, this seems like a good idea, seeing as plants tend to be in these highly sensitive area anyway and why not make them useful? I am assuming, however, that these plants have been genetically modified and so how will the legal/enviromental problems be dealt with. I know that genetically modified bacteria in labs have to be strictly controlled to prevent them from being released into the enviroment; is it the same for plants? I suppose if they used plants the reproduced asexually, then it would avoid the problem of them cross-pollinating other plants and therefore spreading the modified genes. Although, genetically modified crops are not asexual...

Well, again, while the the 1H-NMR interpretation implies that it could be 3,3-dichloro-2-methylpentane, the carbon NMR doesnt imply that as there is no quaternary carbon (in this molecule, the 3-carbon would have no hydrogen bound to it so be quaternary). It is standard that practise while running carbon-NMR to decouple them from hydrogen so that they should all appear as singlets. So if you have a signal that looks like a doublet, I would almost certainly say that it is actually two signals very close to each other. To be honest, if you were trying to do assign this structure in reality, you would use 2D experiments like COSY, HMQC and HMBC instead as well as a C-DEPT experiment. It would make the assignment soooo much easier!

Yes, azo compounds tend to be rather unstable at relatively mild temperatures...they also tend to be highly coloured resulting from the highly conjugated pi-system. Have a look at the dye topic thats in the organic chemistry section if you want more details as I've sready described them once!

Yes, that is why I suggested ester hydrolysis...the vast majority of easily avaliable ester have a characteristic smell to them that disappears during the reaction

Is the carbon NMR proton decoupled? Because it looks to me that there are several peaks that are close together (although its very hard to tell) and not splitting patterns. Also, you have four different proton enviroments but are only quoting three carbons....so according to you at the moment, one carbon has two different enviroments on it; while this is possible (diastereotopic hydrogen's) it doesn't look like thats what you've got. This looks like a beginners type problem, and diastereotopic hydrogens is a little more advance. Additionally, there is no quaternary carbon in the NMR so I can't be 1,1-dichloro-2,2-dimethylpropane (the central carbon here would be quaternary). The doublet which intergrates to 6 hydrogens implies that it is a 1,1-Dimethyl moiety. This would mean that what you think is a sextet is actually a higher order multiplet but you can't see the smaller peaks. If you could zoom in on those spectra and let us know if the carbon is decoupled or not, then we might be able to give you some better help

Ok, there's a little confusion here. Do you want how to make a diazomnium salt of benzene or how to make azobenzene? They are two different compounds. As tiny529 said, reacting the aniline with sodium nitrite and HCl will do it. The HCl and sodium nitrite react first to generate nitrous acid which then reacts to form the diazonium salt. This is a useful intermediate as the N2 group is a vrey good leaving group and so can be used in as a range on intermediates (e.g. Sandmeyer reaction to convert the aryl amine into an aryl halide). However, if you want azobenzene, then you reduce nitrobenzene with zinc and acetic acid. http://en.wikipedia.org/wiki/Azobenzene

Arr ok yes, that makes sence. It's been a while since I've thought about inorganic chemistry with MO theory (sorry Mississippichem I know its your baby!)

I'm not sure that I would like to live on a Lilypad, but I would certainly be interested in visiting them as a tourist. Although I agree, people who enjoy being at sea or living by the coast could potentially be very interested. Especially if there was some sort of harbour so that people could go yatching or using them as a cruise liner base.

Some chemical reactions are indeed ionic in nature. That is one way in which acid catalysis works...for example in ester hydrolysis. The acid protonates the carbonyl of the ester making it more electrophilic (i.e. a greater positive charge). This increase in positive then helps attract a nucleophile (something with negative charge) increase the rate of reaction. Inorganic chemistry (that of metal complexes) is also predominately controlled by electrostatic interactions. Im not 100% sure on the mechanism of hydrocarbon burning, but I don't think it undergoes fragmentation. The mechanism for combustion is pretty complex. Hydrocarbons are have a singlet state whereas molecular oxygen is a triplet. So in this state, they are spin forbidden to react. Normally the initiation step requires a lot of energy to convert the triplet oxygen to the unstable singlet oxygen. Once this happens, a hydrogen atom is abstracted from the hydrocarbon to leave a radical that can then react further with oxygen and the chain eventually falls apart as more hydrogens are removed and bound to oxygen instead.

Yer, this topic has very much spun out of control. But I have got to say, I don't think I've heard as much rubbish on the website than what I've just read from Grouchy Hermit. Im sorry, but that was utterly jaw-dropping stupid!! I don't even know where to start correcting the mistakes in those last few posts! Thanks Mr Sceptic for brining it back...As I said in a previous post, I think something like that would actually make a good great holiday resort. Especially if they were based near other coastal cities to allow quick travel to each of them. Maybe some in the Medderterranian would be good...however, it might interfer with shipping lanes and that