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  1. M

    Alkyl groups donating electrons

    Sorry my explanation was a little vague. The pictures on that site are great though! It's exactly what I tried to describe. Gokul, do you think that inductive effects are fundamentally different from hyperconjugation, or is it just another way to describe the same thing? I guess that you...
  2. M

    Is Aspartame bad for me?

    I have to be skeptical of a guy who appears to be hawking his own version of a diet, and also a guy who seems to list references after his broad statements, but then doesn't appear to list the actual references. By the way, the part on that page about methanol is crap. Yes, a small amount of...
  3. M

    Alkyl groups donating electrons

    The effect is called hyperconjugation and is generally caused by some small overlap of the empty orbital of the carbocation with the neighboring occupied bonding orbitals. You can draw a structure that would sort of represent this by breaking a C-H bond such that you make an alkene using the...
  4. M

    Violation of octet rule

    S is in the 3rd period.... Also, S8 is a ring of sulfur atoms, so there is no violation.
  5. M

    Violation of octet rule

    You mean singlet oxygen? That's different. In that case you haven't added an electron, in superoxide you have one more electron than you do in the regular oxygen molecule. Anyway, I think that I was wrong. You can draw a Lewis structure for superoxide radical where you have 3 lone pairs on...
  6. M

    Violation of octet rule

    Also the superoxide radical, O2 with an extra electron. It's found in biological systems.
  7. M

    Can Hydrogen undergo PI bonding?

    It is theoretically possible to have a pi-bond to hydrogen, the necessary p-orbitals are there, but they are relatively high in energy. So, I would agree with jer83 that it is energetically unfavorable, although not impossible. And there are examples of pi bonds without sigma bonds. I saw...
  8. M

    Organic Chem- acid catalyzed reation

    Well, if you really want to be specific you'd better include benzyllic, doubly allylic, doubly benzylic, triply allylic, triply benzyllic, cations stabilized by adjacent heteroatoms, non-classical carbocations, cations destabilized by inductive withdrawing groups, and on and on....
  9. M

    Spectrometer wanted

    NMR is a great way to do reaction kinetics if the rate of your reaction is compatable with the NMR time scale. Another good one is ReactIR, but that probably out of your price range (I think they are around $30,000), but I'm not positive of that. ReactIR is really only good if you have a nice...
  10. M

    IR Spectrum Query

    IR spectra are usually observed with neat material if they are liquids or oils, which all of those are. You should certainly check to see that the specta are neat, however. You should check out the SDBS, they have tons of IR and NMR spectra for common compounds...
  11. M

    Reaction: Heat will slow down?

    I think the part that you are neglecting is that in your example adding more heat would speed up the decomposition of C into A + B. This decomposition could be unimolecular and therefore could be initiated by adding energy to the system and increasing bond rotations, etc. that might lead to...
  12. M

    Reaction: Heat will slow down?

    Adding heat to an exothermic reaction would cause a shift towards the reactants. Here is a restatement of what GCT wrote, which is right on: For a reaction to reach equillibrium you have to have enough energy around to get past the activation barriers. Adding heat gives more energy to the...
  13. M

    Optical isomers

    Think of light as composed of two perpendicular, two-dimensional waves, one is a sine wave, the other is a cosine wave. Both travel along a third axis. The vector sum of these two gives you the circular polarization that you expect from light. So, if you observe the light at your detector at...
  14. M

    Reason for optical activity(of optical isomers)

    There is some discussion of this in another thread: https://www.physicsforums.com/showthread.php?t=52941
  15. M

    Where to buy buckyballs?

    I don't think that they are much to look at, they pretty much look like graphite. You can buy them from Aldrich though. Bring your wallet, they cost around $250/gram. You can get 25 mg for about $20, however.
  16. M

    Ahhh! Titanium Chloride

    Hmmm...DCM is usually a good solvent for amines, but maybe you need to try some others, especially if your amine is significantly water soluble.
  17. M

    Ahhh! Titanium Chloride

    You extracted the DCM layer, or you extracted the aqueous layer with DCM?
  18. M

    Ahhh! Titanium Chloride

    Maybe try neutralizing with 1N NaOH instead of ammonia. How many times did you extract the aqueous layer with DCM? You might try a different organic solvent too, I have had good luck with amines and ethyl acetate. You might also try a direct extraction after you filter through celite. Add...
  19. M

    How to test for methanol?

    Do you have access to NMR or GC? Those would definitely be the fastest methods.
  20. M

    Ahhh! Titanium Chloride

    If anything, I think you would get the N-hydroxyl amine from a NaBH4 reduction.
  21. M

    Ahhh! Titanium Chloride

    Uhh...LiAlH4? Not really "milder," but a lot better than using TiClx. You can also use BH3, I think, but it's probably going to be pretty slow. LAH reduction of an oxime is generally slower than that of a ketone. Also, I thought that those TiClx conditions used NaB(CN)H3. I imagine if you...
  22. M

    The Chemistry Of Sweetener

    Well, you need some way to tell whether or not the material is still intact. This might be indicated by an obvious decomposition of the material like when you burn a piece of paper or something, but it could also be more subtle changes that might be harder to assay without some heavy duty...
  23. M

    The Chemistry Of Sweetener

    You could test there thermal stability. One of the reasons that some sweetners are used in certain products instead of other sweetners is the fact that they are stable to cooking temperatures. Others will decompose and won't taste sweet anymore. You could also look at solubility in liquids...
  24. M

    Nickel-Aluminum CatalystInfo Needed

    To buy? My Aldrich catalog says around $60 for 100 g. There are a couple of variants available which have somewhat different levels of reactivity, but they all cost roughly the same amount.
  25. M

    Nickel-Aluminum CatalystInfo Needed

    You usually buy it as a slurry in water that is 50/50 wt% RaNi. To get the maxium activity out of it you should wash and decant with absolute ethanol a few times to remove as much water as possible. Ethanol (sometimes methanol) is the typical solvent for these reaction. It's a competent...
  26. M

    Easiest way to find out if oxygen is produced

    You could expose the gas to iron in the presence of water and see if it rusts. If there isn't any oxygen then you won't get rust. You'd have to keep the iron under an otherwise inert atmosphere.
  27. M

    Nickel-Aluminum CatalystInfo Needed

    I've used it a few times in the lab. What do you want to know?
  28. M

    Chemistry Optimum orientation of molecule

    depends on the substituents on the atoms and the stereochemistry. In general you try to minimize gauche interactions of adjacent carbons first, then it gets more complicated if things start wrapping back onto themselves. These interactions can be on the smallish side where energy is concerned...
  29. M

    Question on the boiling points of ketone compared with aldehyde

    As I said above, the bonding in the formaldehyde polymers is totally different. It's repeating -CH2O- units. Hydrogen bonding would likely be a lot less favorable in that case than in solid formaldehyde.
  30. M

    Question on the boiling points of ketone compared with aldehyde

    Yes, most likely. Just like in water, where there are bunches of hydrogen bonded chains and rings and few discrete water molecules. When you say solid formaldehyde do you mean formaldehyde crystals at very low temperatures, or the polymers I mentioned above?
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