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morsagh
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Diamond synthesis
I have (maybe very stupid) idea, just tell me where is mistake or if it is possible. Can be diamonds (i am thinking size a few microns) made by
grignard reaction of tetrabromomethane in diethyl ether or just by coupling of tetrabromomethane in diethylamine solution of lithium?
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DraconicAcid
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Diamonds can only be made under high pressure. At atmospheric pressure, graphite will be the thermodynamically favoured product of any carbon-forming
reaction.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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morsagh
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Why so sure? What about chemical vapor deposition? And still, i am thinking only about micro-sized diamonds
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DraconicAcid
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Because you can look at the entropy and enthalpy of formation of graphite and diamond, or look at a phase diagram, and see that graphite is simply
more thermodynamically favourabel at all temperatures at standard pressure.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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morsagh
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Think about intermediate, that can be C(CBr3)4 because of better reactivity of substituted carbon no?
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aga
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No. Just No. It will not work.
(Re)Read DraconcAcid's explanation.
Edit :
If anyone makes Lead into Gold, then Gold will quickly have very little value.
This is the Conumdrum of the Philosopher's Stone.
Same goes for Diamonds.
[Edited on 9-11-2015 by aga]
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careysub
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Chemical vapor deposition works to grow diamond because of boundary effects - you can add carbon atoms to an existing lattice in a very low pressure
environment at high temperature. It is thermodynamically favorable to add an atom to an existing diamond lattice surface.
No normal chemical reaction conditions can do this.
Commercially industrial diamonds can be made for less than $1 per carat. Gem quality diamond can be made for much less than the going market prices
for natural gem diamonds, but are sold at about the same price - the makers being happy to join the virtual diamond cartel that exists worldwide (a
tacit collusion by all diamond sources not to undersell each other).
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zed
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There is no real shortage of Diamonds. Global output is carefully controlled, by the folks at DeBeers. When somebody whips up a new process fer
making Diamonds, they attain membership to "The Cartel" so to speak, and they become associate Diamond-eers. You probably have a choice, in the
matter. Join up, or face the possibility of having a terrible accident.
Diamonds maintain a high price, at present. But, the price has been known to crash, pretty damned hard. Very useful industrially, but
otherwise....just a very hard, very pretty, glass look-alike. Been hyped fer a long time, but like the "Tulip Craze" of a bygone era, it is an
artificial market. Diamonds could slide in worth, and become relatively valueless.
Cubic Zirconia, looks just as good, and it is usually available, cut, for about 10 bucks a Carat, or so.
Now, if you could build a time machine, we could circumvent the whole "hard to grow diamonds" problem. We could take some massive CZs back to the
1800s, trade 'um for 35 dollars an ounce...Gold, and return home zillion-aires.
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Upsilon
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Quote: Originally posted by aga  |
If anyone makes Lead into Gold, then Gold will quickly have very little value.
This is the Conumdrum of the Philosopher's Stone.
Same goes for Diamonds.
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Not necessarily. Synthetic diamonds are already in wide production for use in diamond-tipped tools. Diamond-tipped tools would cost a small fortune if
they used natural diamonds. Natural diamonds retain their extreme value, well, just because. People like natural diamonds for jewelry even though
synthetic ones, which are chemically identical (if not even more pure) are much cheaper. People are irrational.
I imagine if gold were able to be synthesized in significant amounts, "natural gold" would still retain high value for use in jewelry, while all
practical applications move to the synthetic gold.
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j_sum1
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What has happened with diamonds is that there exists a syndicate that has simultaneously controlled supply and inflated demand.
There is no guarantee that the same would happen with synthetic gold, if it were ever to be produced (which I doubt).
In any case, diamond production remains sufficiently tricky as to put it out of reach of an amateur. Which means that the status quo on diamonds
remains.
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Little_Ghost_again
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you can have dead people turned into diamonds
Dont ask me, I only know enough to be dangerous
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Upsilon
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| Quote: Originally posted by j_sum1 |
There is no guarantee that the same would happen with synthetic gold, if it were ever to be produced (which I doubt). |
Who knows, maybe someone will figure out how to do it (somewhat) economically. There is definitely motivation to synthesize gold via nuclear means if
it has the potential to reduce the price of consumer electronics (may not make much of a difference in the price of individual devices but it would
save the manufacturer a boatload on precious metal costs).
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careysub
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| Quote: Originally posted by zed | There is no real shortage of Diamonds. Global output is carefully controlled, by the folks at DeBeers. When somebody whips up a new process fer
making Diamonds, they attain membership to "The Cartel" so to speak, and they become associate Diamond-eers. You probably have a choice, in the
matter. Join up, or face the possibility of having a terrible accident.
Diamonds maintain a high price, at present. But, the price has been known to crash, pretty damned hard. Very useful industrially, but
otherwise....just a very hard, very pretty, glass look-alike. Been hyped fer a long time, but like the "Tulip Craze" of a bygone era, it is an
artificial market. Diamonds could slide in worth, and become relatively valueless.
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This has been a topic of some interest of mine for decades.
Markets in ornaments are always 'artificial' (there is no necessity, leading to demand). The diamond market though is completely different from the
tulip craze, or other economic bubble.
The price of gem diamonds, adjusted for inflation, has been stable now for more than a century (except for product dumping attacks conducted by De
Beers in the past to shut down an uncooperative producer). This is impossible in any competitive market, and there is no other equivalent in any other
commodity.
Diamonds once genuinely were rare, about the only know source was India. Then the diamond pipes in South Africa were discovered and suddenly there
were discovered around 1870, and suddenly they were not rare any more.
This created a problem for a commodity with no natural demand.
The result was a brilliant marketing campaign to drum up demand for a product in excess by De Beers which had established a monopoly on diamond
production in South Africa in the 1880s.
Bestowing diamond engagement and wedding rings is not a tradition of long standing. It was impossible before the 1870s for any but a tiny fraction of
the world to own one.
The practice of bestowing diamond rings began around the turn of the century as a result of a marketing campaign.
During the Great Depression, when demand for diamonds collapsed, De Beers supported prices by hoarding inventory, at one point holding almost a
decades supply unsold.
They then set themselves to convince *every* bride in the Western World that their husband-to-be did not really love them unless he spent two months
salary on a diamond engagement ring (yep, the 'correct' outlay was in the ads). In 1940 only 10% of U.S. marriages involved diamond rings. By the
1960s it was 80%. As the U.S. market maxed out, the pitch shifted to Japan (going from near zero of around 80% in the 1990s), and recently to China
(currently up to 31% from zero).
Any commodity that can be bought by any one who wants one at a stable price cannot be rare. In fact natural rubies, sapphires, emeralds are all much
more rare than diamonds today.
The sales pitch of emotional attachment, combined with stable pricing is essential to prevent people from starting to hoard, and then buy and sell
diamonds like, err, a commodity. A huge number of carats have passed into private hands since the 1870s, which creates an enormous potential source of
diamonds that theoretically get dumped on the market.
Theoretically.
Because there is NO market for diamonds that do not come from diamond producers! No diamond dealer of any sort will buy them from you. They do not
dare, or their ability to obtain diamonds from the virtual cartel will get cut off.*
De Beers actually controlled the world market until the 1990s when vast diamond resources opened up in Russia, Australian and Canada. But all parties
found it agreeable to follow De Beers pricing, and avoid flooding the market, and bring down prices.
I would like to get a small natural diamond crystal for my element collection, but they do not exist on the world market. Virtually all diamonds are
cut into gemstones. Perhaps I can be a nice industrial quality one.
*Perhaps some Internet billionaire will decide to set up a new line of business and begin buying and selling "used" diamonds. Only a rich, powerful
independent person could dare to do this.
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j_sum1
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Clarification.
There is no guarantee that the same market forces would operate on Gold as have operated on diamonds. I think the situation is vastly more complex
from an economic standpoint. For a start, there are more players. And there are more natural sources of Au than for diamonds.
Additionally, I doubt that synthetic gold will ever be produced in any quantities more than for academic interest. I don't see any technology
developments on the horizon that would make it a feasibility. I'd love to be wrong.
I think extraction from sea water is a far more likely scenario -- and with similar economic outcomes to the synthetic route.
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j_sum1
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| Quote: | | I would like to get a small natural diamond crystal for my element collection, but they do not exist on the world market. Virtually all diamonds are
cut into gemstones. Perhaps I can be a nice industrial quality one. |
It's not real pretty, but I got some of these for my element collection.
http://www.ebay.com.au/itm/1-Carat-Raw-Natural-Uncut-ROUGH-D...
Roughly 1mm in size. It's not a lot but it works ok.
I also got some synthetic diamonds from the same seller. The two side by side makes for a good discussion point.
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careysub
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| Quote: Originally posted by Upsilon |
Who knows, maybe someone will figure out how to do it (somewhat) economically. There is definitely motivation to synthesize gold via nuclear means if
it has the potential to reduce the price of consumer electronics (may not make much of a difference in the price of individual devices but it would
save the manufacturer a boatload on precious metal costs). |
Problem is - if an efficient nuclear production process existed, it would still be as expensive to produce as plutonium, over $1000/gram. And in fact
a production process for gold that is as efficient as plutonium does not exist.
The only "cheap" source for precious metals that has been proposed is asteroid mining. The problem with this idea is that the entire world's market in
precious metals is probably not large enough to absorb the scale required to make space mining profitable. If you opened a space mining operation,
bringing back enough material to be profitable (at current prices) it would drive the price down. Maybe some day, when the economics are radically
different.
The best way to get cheap gold is to convince people to stop buying it as a store of value. Good luck with that.
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zed
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Yeah, in my estimation, current Gold prices are the result of speculation (or loss prevention).
Gold is a valuable industrial metal, and it makes nice jewelry. But, it is it's role as an investment, or a hedge against total loss, that has
produced the current high price. When the Stockmarket crashes, and the Real Estate Bubble bursts, and it looks like the whole world is going to Hell
in a HandBasket.....That is when folk double-down on Gold.
Things stabilize, and Gold goes down.
Currently, it is actually more expensive than Platinum. And that, just isn't kosher.
Might be due for another plunge.
In the meantime, I yearn for economic good times. Folks speculate, to a certain degree, on Platinum too. But, me like Platinum. Very useful. And,
currently, very spendy. I will never again, fail to stock-up, when the price is low.
Ah, must be some good economic news somewhere. I just checked Platinum, and the price is plunging. Around 900/Oz.. Drop, drop, drop! Baby needs a
new pair of shoes! http://www.infomine.com/investment/metal-prices/platinum/all...
Buy low, sell high. Or, keep it fer awhile. Just avoid buying high, and selling low.
Better folks than us, have become bloody stains on the sidewalk, after making that mistake. Gosh! Sounds a lot like chemistry itself, doesn't it.
[Edited on 10-11-2015 by zed]
[Edited on 10-11-2015 by zed]
[Edited on 10-11-2015 by zed]
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careysub
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Remember that old adage:
"Buy sheep, and sell deer."
Or something like that.
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Dr.Bob
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I do remember hearing when someone was able to make gold in a linear accelerator years back, but the cost was much higher than gold was worth, as
careysub stated. But gold is quite useful, so the price will not drop too far or people will use more of it in electronics and other areas. The
reason that platinum has dropped is that car companies have found other metals and platinum mixtures that work close to as well or better then
platinum in car catalytic converters, as well as many other chemical processes. Most chemists now use palladium for hydrogenations, but Pt certainly
is very good for it, but much higher in price, and sometimes, too reactive.
But synthetic diamonds and lab grown gems (ruby, sapphire, emeralds, etc) are now readily available and most look better then any natural gemstone
that normal people could afford. There are at least two companies making synthetic diamonds up to 3 carets, and Cree/Charles Colvard can grow
moissanite crystals the size of your fist or larger, so no shortage of them, and they look great. But aluminum oxide makes beautiful gems, and it is
very stable, and harder to damage than a diamond, which can be burned like coal in a fire. Lab made sapphires are really cheap and very pretty.
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zed
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Seen quite a few Synthetic Stones. The tastiest of them all, was the Gilson Emerald. Not Cheap in those days, but unequaled in beauty.
Cutting and polishing Emeralds, isn't a healthy occupation. Beryllium.......it'll getcha!
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Upsilon
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| Quote: Originally posted by zed |
Cutting and polishing Emeralds, isn't a healthy occupation. Beryllium.......it'll getcha! |
They probably do this underwater so the dust doesn't get everywhere. I know that's what I'd do if I had that job.
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rocketsurgeon
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If there were a way to clear diamonds of optical impurity that would probably be more profitable. As you probably know that the clearer the higher
price. so buy cheap abrasive grade diamond and make it clear like a high quality stone.
"there just a pile of idiots" rocket surgeon
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IrC
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| Quote: Originally posted by DraconicAcid | | Diamonds can only be made under high pressure. At atmospheric pressure, graphite will be the thermodynamically favoured product of any carbon-forming
reaction. |
I don't agree. Several patents for CVD diamond exist. Also microwaves. You can make diamond dust from graphite in a microwave oven. Patents exist
going back to the early 60's. Combination approaches have also been successful using less pressure, less heat, and microwaves. Most work in this area
were attempts at larger crystal size but far as I know diamond dust (or very small crystals) is the usual outcome. Will not impress the wife but great
for tools.
"Science is the belief in the ignorance of the experts" Richard Feynman
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Dr.Bob
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Draconic is correct, "graphite will be the thermodynamically favoured product of any carbon-forming reaction." Any method that attempts to make them
in non-high pressure systems will have to use a kinetic or catalytic driven method to force the carbon to add in SP2 fashion. This is somewhat
analogous to getting trans alkenes from thermodynamic methods and cis from kinetic methods. But in general, the thermodynamic product is always much
easier to make than the kinetic one. Thus, making diamonds that your wife will like is always going to be much harder than making tiny diamonds to
cut concrete with. But there are at least two good methods for making up to 3 caret manufactured diamonds that will fool most non-experts as well
as several other ones for diamond-likes that are even less expensive.
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IrC
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Can you explain the mechanism behind CVD diamond from butane gas at 800 Torr (has worked down to 40 Torr), 400 C, 800 watts at 2.45 Ghz? The process
works better closer to 1,000 C but falls off at temperature in the plasma over 1,100 C.
Attachment: EP0305903B1.pdf (64kB)
This file has been downloaded 337 times
Attachment: EP0418837A1.pdf (367kB)
This file has been downloaded 338 times
I have around 100 patents in my database on diamond synthesis but no time right now to go through looking for the ones that pertain to CVD. When I can
I will search through them and post a few more.
"Science is the belief in the ignorance of the experts" Richard Feynman
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