Lecture 04. Selectivity

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Lecture 04. Selectivity
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UCI Chem 201 Organic Reaction Mechanisms I (Fall 2012) Lec 04. Organic Reaction Mechanism -- Selectivity Instructor: David Van Vranken, Ph.D. Description: Advanced treatment of basic mechanistic principles of modern organic chemistry. Topics include molecular orbital theory, orbital symmetry control of organic reactions, aromaticity, carbonium ion chemistry, free radical chemistry, the chemistry of carbenes and carbanions, photochemistry, electrophilic substitutions, aromatic chemistry.
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I want to start up by just considering a very simple
reaction here we have some sort of side and have some sort of Floro out meaning you tried to make Anita Roddick that is 1 of the 1st reactions you learn in soft Morganica making the disease the Williamson the synthesis arm so that 2 possible products here and I want you to walk called him a and like you to try to assess which of these you think forms faster and which of these things you you think forms more slowly or what you think is going to be the major product in this reaction and the the case of the flu In this so
that the other byproduct is chloride in this case it's thing an iron chloride in each of these cases this is definitely an irreversible reaction the chloride is not going to displace the bauxite and iron to regenerate the starting materials ,comma and in cases where reactions are irreversible where they don't go backwards you get the product forms fastest product that forms fastest is the major product in the reaction so in this case what we expect I hope it is your
intuition on the Hill attack here only a little carbon faster than you attack here on S P
2 substituted or their speed to hybridize carving out and I want us to be able to analyze reactions in terms of reaction coordinate energy diagram so we're going to start incorporating a new type of diagram yes the you in rare cases obviously generally generally the conditions some are very hard to sway 1 way there but I'll give you an example where possible OK so in irreversible reactions you get the product becomes fastest 20 graphically .period depict this idea and I wanna start off as found by pointing out that I'm going to show you a diagram with a completely different type of y axis so so far this course we've been talking about molecular orbital
energy diagrams where some sort of an energy axis on he and I look at the energies of molecular orbitals
meant that is little energy lines this is completely different and not grabbing molecular orbital energies grabbing free energies of starting materials were free energies of products you measure free energies and cake cows from all and that means you can convert those into numerical ratios 1 . 4 K Kallstrom on its axis equals a factor of 10 those other molecular orbital energy diagram those were an electron volts you don't convert those in the factors of 10 so when we write reaction diagrams there's also this mystical some sort of X axis called the reaction coordinate normally that means something like a bond distance as oxygen gets closer and closer and closer and closer to carbon you could consider this to be a carbon-oxygen bond distance if you wanted but we
generally don't worry about putting units on their or assigning it so it's good diagram this reaction all draw the starting materials are right here
sort of in the middle and I want to show that this has to possible directions that it can go so in this case would get it going on in 1 direction over here generate some products but there's also an alternative reaction pathway 1 of these directions will lead the product a in 1 of these directions will lead the product the which of the sides here goes to prop which which product in my depicting over here now this is a product of we said that we like this because we're attacking to a regular reaction not on as Peachtree hybridized center are intuition I hope your intuition is that they should be faster and they should be
slower and the reaction that we believe should be faster should have the lower energy
transition state while put a year and also would be you tend to let me go and put a little energy line there now by taking an Aymara cruel denim are for this reaction probably would I would see as I would see this product in there who knows what the deal would be 88 per cent 94 per cent doesn't matter the important point is if I don't see any of this in my hand a mark just based on the limits of detection by I can probably say that the ratio was greater than 99 to 1 regardless of what the total yield is but I can't detect any of this but I can only detect about 1 per cent during maybe sometimes less depending on how Our how much signal-to-noise you have it by CIA 99 to 1 or or some All I really know is greater than 1991 but I can't detect that might arise and it's at least a 99 ratio what does that allow me to say about the free energies of these 2 transitions just by looking at a lot of proven among it at
least 2 factors of 10 in favor of this it's at least 2 . 8 K Kallstrom or greater in Anaheim our lower energy to good product and we give this
we give this on this difference in free energies between the transition state this designation Delta Delta G double-decker here's what that work where that comes from we label the energy to go to this difficult transition state as delta G double dagger double dagger refers to a transition state that's the transition state energy to build a product be an opera little be subscript there and then we would label this transition state energy as the difference in energy between study materials and product that there's a little double dagger home it's the transition state and the difference between those 2 delta genes this is a Delta has a different advantages that difference between these 2 differences we label is
this this is a very common phrase and all we know is that this is greater than 2 . 8 Kelso from all
we don't know if it's for we don't know if it's 7 we we don't know if it's probably not a hundred K Kallstrom all but this was what correlates to a greater than 99 1 ratio greater than 100 1 ratio so we can construct a pretty arm scholarly diagram despite looking at at accrued in Amman I would expect you to be able to do that to remember as long as we're drawing reaction coordinate diagrams and and measuring things in K Kallstrom from I want you to be able to converge on these types of free energy differences into ratios and I want you to be able convert ratios into free energy differences and and dropped reaction according to which of these is more stable a mail drop that so many things drawn here so it is sort of focus your attention on which of these 2 products is more stable product this b is more stable and more stable by a lot what's the important point here I'm
going to ride it out so we don't forget we would like to thank you for the work it
is I and what I ought to do that to tell you more boldly about half the time less stable products from fast so if you came away from sup more organic chemistry thinking that more stable things form faster you completely missed the point you completely lost it somewhere when they were give you some special about half the time
less stable things form faster so we really need a seperate the stability of the products from the rates of chemical reactions because they don't say the same thing so just to come down here we can now modify our diagram I'm just going to
pull this bore down a little bit more saying here is that products be which forms more slowly is actually more stable than product and we don't know how I didn't give you a value for that but I'm showing that with my diet it has to do with residents residents donation between these long periods and by star and you don't have any of that residents in India looking OK so rates are so low rates of chemical reactions super important but some money to another reaction Cornyn diagram for a hypothetical reaction I'm going to label this for a reaction where products were starting material this is different from what I showed over there now I'm talking about some hypothetical reaction where a goes to be and what I want to do is I wanted to draw
all this this thing called the transition state and ponder on the fact that there isn't really something there is no species called the transition state reaction the transition
state this summer as some arrangement abounds where you got halfway bonding half of a bond a bomb attack Foreman have broken or set a bomb there threat warning of broken you can never isolate anything like that the bonds have formed or have broken the total fiction there isn't really any species called the transition state at any point in time in your reaction which is suspected but you can pretend that there is any time I can measure a
different Europe K calls per mole I can convert that into numerical ratios even know there isn't anything called a transition state if I pretend there is I can now
measure energy difference here and will call this delta G double dagger going to the transition state from a as long as I can measure energy difference in take us from all I can convert that into factors of 10 printing America Lynch's let's do that that's brought the equations that are necessary to make that work I I it was but so this would be the rate equation for that chemical reactions we have rate reaction rate is equal to something called the rate constants times the concentration of dead 10 times more a reaction
is 10 times faster get one-tenth as much as Sarah had 10 times more solid reaction is 10
times lower concentration matters if the rate constants is 10 times bigger your reaction is 10 times faster than the rate constant is usually correlated well all this Carol pushing that we do all Estero pushing all the stuff that were doing in can 201 Aero pushing is related to rate constants when you get a chemistry 202 you'll talk about reaction kinetics and start incorporating concentration of those ideas because they obviously influenced rates of chemical reactions OK so how do you convert those free energies I have over there ratio there's the equation that you use it's equal to a numerical ratio of rate constants a numerical racial rate constants has to do the rate constant for the reaction the
1st is this other mystical thing so what is this telling you
it's telling you if you have some sort of a delta G value here and I'm just going to arbitrarily assigned a number here to 23 K Cal's promoter for that kind of an energy barrier so you have an energy barrier of 23 K cost from all there's 2 different pathways you can go this direction which is not very fast or you can go the opposite direction where there's no energy barrier and that's would pay double it's the it's when there's no energy barrier when just fall in love with this energy Hill How fast is that so this is equal to the fastest possible reaction when there's no energy barrier the problem and we can put numbers on that and I'd like you to know what those numbers are what is the fastest possible rate constant there's some limits on will get to that in just a 2nd but 1 thing that I want to do
is noted there's temperature in this equation and that you can use that in a laboratory
temperature is a part of this equation for every reaction you run and you don't have to know anything about a year of the year and you can make some good rule of thumb in estimates for health temperature is going to affect your reaction and here's the rule of thumb that I'd like you to use in the less and if this is this is the end easily suffer most reactions that you run lab if you turn your
thermometer if you turn the heating backed up by 10 degrees you should expect a reaction get twice as fast you go by by 20 degrees 4 times we will
buy 30 degrees 8 times faster now you're starting wouldn't you like to get your Ph.D. 8 times faster you are not and when you read some procedure literature and your following the procedure you don't have to sit there and be a victim of the way the procedure was when you have the choice to raise the temperature in your reaction and make your reactions go faster and roughly follows the school it's actually a pretty good will most of the reactions that occur between 1978 and 100 degrees which is most of the reactions will so it's a very good will from now the downside is your side reactions also go faster and sometimes they will little bit faster than the 1 you want ,comma but this is just a simple powerful to comply if if you're worried that she would have to wake up at 2 AM to do my work up world turned the heat up and then you can work the reaction of at 5 PM and then go home for dinner so simple rule of thumb
that comes from this equation right here OK so let's talk about this fastest possible rate what is the fastest possible rate constant when there's no energy barrier furious following not the
energy deals were going to put some limits on that I'm very frequently in this class .period and mentioned things related to rate constants and I want you to know the range of values rate constants can have now unfortunate that maybe this is good for us just to keep alive simple and during this quarter when registering a lot of Aero pushing you almost never going to know anything about K the absolute value of k I'm very Freakley going to give you a relative rate constants kiss reaction is 10 times faster than that 1 I'm not telling you how fast either reaction is I'm just telling you that 1 of them is 10 times faster this reaction is 10 times slower reaction is twice as fast so did a lot of information about relative rate constants which you your rarely going to know the absolute value of the rate constant offer any elementary reactions when he couldn't put some limits if you see anybody spelled out some rate constant that doesn't fall within this range you need to question the validity of that sold the stake 3 different cases of elementary reaction processes and sulfur you know molecular reactions and there could be something like an electoral cycle agreeing opening where 2 molecules don't have to collide with each other which is 1 molecule is sits there does something suddenly that's the you know molecular reactions you'll find that the slowest possible rate is somewhere and I'm going to be a little bit fuzzy on DM per 2nd it's like a frequency tenderloin is 8 times a 2nd that's how fast this bond might break if it was very
unfavorable so that some the slowest possible rate
and correlates with the year-long timescale if you run to the calculations we typically don't care very much about reactions that takes several years right you're not going to write anything in your thesis about reactions that takes several years so of somebody says my reaction occurs whether a rate constant again like the constant understand that you might want ask them how they measure that on the scale of and ii tremendous of great focus the rate constants for you know molecular reactions things were things to things don't have to collide with each other are usually greater than that and they are always in every single case lower the this value this is the fastest possible rate constants and that's the case double dagger that's the fastest possible rate constant for the on you know molecular processes and what is it that sets that limit you go to the wall now this can be moving all you're getting close to it but this can views around faster or slower it's the vibration of bonds no bond can break faster than it vibrated it's vibrating this slowly it can suddenly be out here faster than library the 2 Adams can move away from each other only as fast as their vibrant so this is the vibrational frequency that's the frequency of things like C C and C H stretches in your IRA spectrum if you convert in wave numbers or whatever you're using in your eyes are spectrum a correlates with this as a typical CC CH bond vibration frequencies measured in hertz OK so it's not about molecular reactions but that sent reaction that I showed you before with the Fox side attacking a little chloride is so here we have different units now notice in the units we have a molar the measurement number that sort of reminding you that concentration matters if I had 10 times more reagent reaction will go 10 times faster event 10 times more solid it's more dilute their actual go 10 times slower so this is just a reminder that concentration matters when you require 2 things to collide with each other to molecules to climb new requirements oxides to collide with similarly court so in by molecular reactions your rate constants will always be greater than theirs and again this correlates with sort of year long timescales you don't care about by molecular reactions that take it takes years to operate the fastest possible by molecular rate constants
it's this something on the order of 10 to the 90 per more per 2nd what is it that sets fundamentally the limit
on the fastest possible readable by molecular reactions it's diffusion these can react faster than the diffuse toward each other and this number is a little bit sort because different solvents have different viscosity right if you dig your reaction in the in molasses standard action that the diffusion will be very slow diversity during action and he there it is very low viscosity things diffuse around in the solution very quickly so far are molecular elementary reactions the fastest possible rate is limited by diffusion so the when you look at these numbers here the transition state energies if it matters whether you're thinking about you know molecular processes thereby by molecular processes this sort of a sort
of rate ratios can get here and so this is diffusion and this is bond vibration OK
if somebody gives you some number that's outside that range question they hope will wait a 2nd I thought that diffusion was limiting the rates of molecular reactions can you come up with tender the 11th by molecular process but we don't have any examples of term molecular reactions on Boulevard Elementary actions you molecular by molecular Italian industry the end of the 2nd half of the year the in which would would not put up with it the money but suppose you
promised advises that you going have that kill bromide ready by tomorrow the were to get a
strip that sigh logo but this is the tribunal's eye-level silo group I get a strip that I'll Bothman Runako reaction which retinal commentator bromide convert the call to the Rome I gotta get that sigh Leiter off peak and then I can convert that into the bromide pretty typical reagent would be period Dean hydrofluoric acid on you can buy that sort of O sold complex to source of fluoride and compose just before he started class today he set up your reaction political Indrawati LCs for this reaction here but that's pure Dean it's assault make by mixing period means the hydrofluoric acid on it's not really important it's
so it's milder than display nature of OK so the Bulls ATM user here reaction and here's your silo
Letha published starting material and then down here just before you came into class today it's 10 AM But suppose you till seated again ran indicted he'll see you know you see something that looks like this that's 10 A.M. what's your reaction going to look like a 12 o'clock at New this is the fundamental questions and the important point is that rate constants affect how you organize your time but time to get the thing worked up by this afternoon and get the next reaction started 1 I won't have time what can I do to make it faster or slower for better organize my time Oh no I can go anywhere
the seven-night the Teal c my reaction to find out what's going to happen I look at this
and I can make some pretty strong guesses about what is going to happen with this reaction and what I want to do that I wanted just Graf helps the reaction progresses and measure the amount of product that's forming this reaction cancel those wishes good encircled by drawing 0 8 AM at the start of the reaction the others write a M P M this is not this is it and I want to try to do so here's 10 AM and were interested in what's going to happen around noontime so I've already showed you what's happening at 8 AM it's all starting material you just said the reaction here is 100 percent product In zero-percent product is down here at the bottom and so at the beginning of your reaction you have zero-percent product much product you had at 10 AM about 50 per cent of this roughly graph that here there is money and 2 percent mark and so the question arises is how much product is going to have a 12 o'clock so here is what I would love to see and that's totally wishful thinking right if this is what you're thinking is going to happen then you don't understand the rate constant and the relationship capitalized on the way to think about this is not in terms of rate constants you need to start thinking and half half-life what this tells you what that feels he is telling you is that the half-life of the reaction is about 2 hours if you go another 2 hours you will use up
another half of the leftover starting material so 50 percent my surname Cho left over Americans
half of that in the next few hours so how much product line have at 12 o'clock you have 75 per cent and
then at 2 o'clock in the afternoon now I have 25 per cent starting here left over how much my going to consume the next 2 hours yeah announcement and be another 12 per cent so now I'm not very good at math it's going to be about 80 per cent and go another 2 hours another half life and I've used up another half of the remaining stuff and then I keep going out here what you'll find is that it takes about 8 half lies and I'm an abbreviated that with T-1 hand it takes about a half lives to reach completion and I mean really complete To reach greater than that now
usually you can work it out at 99 percent completion and be perfectly happy with the deal but you know we we try to be even better
than that it takes about a half lies reactionaries completion and the words reactions don't go like this because most reactions of 1st order in starting materials and that red pen is not not every reaction but most reactions follow a first-order dependence and starting material that means the rate of the reaction gets slower and slower and slower as I have less and less starting material there so again when you set up a reaction you can't predict what state the
reaction is going to be in at 3 o'clock in the morning do I really need to come and work out between the morning now there's no chance that that's
going to be ready because after 8 hours will it was only half done if you reaction is have done after 8 hours how long will it take to reach completion Denny's don't come until seeing every hour you'll know very very quickly what the world with the cost of that reaction is going to be you're not you're not doing work by Teal c reactions that are obviously going to take days to run sold use this information their all if you reactions that follows 0 with water dependence on starting materials those reactions are rare there's something organic talent catalytic reactions will obey those rates there are a few that involved 2nd order dependence on starting job but most reactions of a first-order dependence on starting Mitchell concentrations OK so the super important idea this idea that on that so
really what govern our day-to-day activities in the laboratory and you need to think in terms of at the beginning of the month
something and rate constants human I'm going to tell you all this reaction is 10 times faster than 1 is 10 times slower we organize your time think lies because you look at the clock in the laboratory and that's measured in minutes and hours Silver for technical you know molecular reactions were 1 thing goes for 1 thing there's a pretty useful on weighted to convert half livestock and I should say it is approximately 12 of the exact number of here we go
so the way to convert rate constants those things in measured perceptive in Darfur the 2nd is a simple
equation natural order to a now I'm too stupid to know a natural log too is I just know it's something like 1 irony remember what it is I won't even try so is what I do there go and that's close enough every single time for me trying to get things done and estimate how long things going so that what is approximately universe of the rate constant and that's a good enough on 4 by molecular reactions where there's 2 different regions that's only true In both of agents are present at 1 molar now usually run reactions with Inzamam-ul-Haq smaller farms so Europe will be a little bit offer by molecular reactions focus and so for on so it's important to think in terms of how half lives a year in the lab doing stuff in organizing your time let's
change gears here we've been talking about kinetic reactions where the rate of the reaction the determines from the product selectivity and I want switch around now and talk
about equilibrium the reactions of pneumonia give you an example of and the mechanism for this is a little bit complex because it involves a lot of proton transfers I'm not going to draw the mechanism for for you this is a parent toluene sold finding gas is frequently used as a catalyst for forming and idolizing acid tells and if you do a hydrolysis reaction in water at 0 degrees the 2 possible products that you'll get that you can see and it depends on the conditions for the reactions so in this product both the Modoc senior party groups had been idolized off so
you can see there's a mixed acetaldehyde when and you consider imaginatively Kerviel grew so you might realize those Lockheed this latter town this cycle
against her but there is another product that you can get which is this ethyl ester and you can get either 1 of these depending on the reaction conditions and that comes from hydro lies not dismiss foxy group the site had realizing cleaning his carbon-oxygen bond in the rain and idolizing often now the product ratio depends on the conditions the reaction if you stop this reaction after 20 minutes and I always advise you start the Teal c reactions as soon as they start because of you always wait
until 10 hours because the procedures said 10 hours before you take your 1st you'll see him no idea what happened in reactor review was done in 3 minutes and you should work it out and managers started decomposing after that there's
Letizia after just 20 minutes this that the main product for the reaction has cleaved the rain and I'm a foxy group has been idolized off but if you wait 12 hours newsletter said if you get a totally different results you can't even detect that that ethyl ester in there it's all what has happened in this reaction all in terms of change the time the conditions are exactly the same as is the case where this minor product that you see over here is the result of an equilibration of starting materials are of the products
under the condition of the reaction it turns out that the products equilibrate there's a huge entropic advantage to having this
alcohol In the presence of an acid catalysts for ministers through fissures verification reaction and on drawled acid catalyst there but we don't need to talk about the mechanism the 6 steps in this in the Aero pushing mechanism the point is that under the conditions of the reaction this is occurring and if you wait long enough it will go to the summit dynamically more stable ring product here so this is what we what we would call a reaction that's under thermodynamic control if you stop the reaction very quickly this identifies 40 the kinetic product the product that forms fastest which tells you something about transition state energies tells you this
is forming the initialing much faster In this other products but then we know that these can equilibrate Seoul immediately we can draw some sort of an energy diagram based on
these ideas and what we know from this final result here seat is greater than 99 less less than 1 what's that about the difference in free energies between those 2 products I'll call 1 of them that close ring over there I'll call the lack tone and this other 1 will call the hydroxy Esther we don't know the difference in Fremont free energies but it's at least 101 ratio therefore it said leased to . Kallstrom and initially the hydroxy after was forming at least 20 times faster but 595 is like 2001 right this was for at least 20 times faster so we know that and maybe none of this was forming maybe all this occurred through some equilibration reactions so we don't know maybe that the the difference in free energies here was was a thousand K girls from all but we know is at least on not a factor of 10 but a factor of 20 which is on greater than 1 . 4 plus point for that's a factor of 2 2 and this is a factor of 10 1 . 4 promotes a factor of 10 so we know that the
difference in transition state energies going that favored this was at least 1 . dk Kallstrom all lowering energy maybe none of this form
directly maybe it all goes to this 1st and then equilibrated that OK so it's important to look at numerical ratios he'd always be willing to do and quick to to translate those and a free energies that you can put a diagram just from looking at Teal c you could start to drop free energy diagrams by estimating his tender 1 1 the 1 equal amounts that's very powerful stuff OK so how can you learn about just reaction rates have Mueller about rate constants for reaction which reactions are fasting which reactions slower In the end it we have to do it for the I think you guys recognize this probably isn't deals all the reaction it is
amazing how pathetic cycle Eckstein as as a diesel fuels older partners that's 1 of the worst deals all the reactants unimaginable In
so here's closely related to undo all the reactions on here's another 1 where they had to make sure substituent in there and the only reported this time in the presence of silica gel so for some reason adding silica gel accelerated that can I can make some guesses but that's not the point of this so in this
reaction they get a 29 percent yield and this reaction was silica gel get a 64 per cent yield and so which of
these is the faster overall reaction this is usually what you see when you read the papers it's stuff like that an answer is you can't possibly know which is the faster reaction you can't know which is the better reaction here the information they didn't give you as they were heeding that first one at 200 degrees to make it work because it's so common it looks good until you realize that and how often have you wanna reaction at 200 degrees that's obviously a slow in crummy reaction and you don't know that until you look at the temperature
that's what tells you it's slow in coming but if we look at this 1 over here they told you the temperature actually it's 25 degrees
Celsius but until you read the fine print you don't realize what's going on when you read the experimental they let this thing sit for 5 months the point is that you will not learn about reactivity if you spend your entire time and sought more organic chemistry here some introductory chemistry course hoping to learn about which reactions are good and which would react in the event that the only way you can say about which reactions are good and which reaction to that is not looking to its by looking at rates and times are sorry temperatures in time the of the so I'm going to give you mechanisms complex and you're going to be asking yourself do you which way should start pushing arrows Is this way good this look like something out of the fast work depends heavily seen something similar in the literature that occurs quickly and the only way to know which things are quick or things that occur at low temperatures and rapid reaction times so again it's not sufficient to look at yields affect those carriers very little about which reactions are fast which reactions slower so this very few tabulated listings arm of actual reaction rates found and you need to pay attention to
the to those other details on the show
you how to extract some information the the physical the MOU Guyana howled all reaction in all liters this pipeline is very nucleophilic and attacks the carbon and a mechanism is not what I'm getting at here I don't think that's important for this month for the point that I want to make the point that I want to make is that if you're reading the paper you need to home in on this they called the reaction to minus 70 degrees when they did it and what that tells you immediately is that every single euro pushing step in this mechanism must be fast if there were any still slow steps In the reaction mechanism they couldn't possibly have called this number minus 78 in that it work so when you draw the mechanism
you know every step in the mechanism is fast and every time you draw a similar mechanism on your paper those steps will be faster they look like the steps in this mechanism this is immediately
given a wealth of information about what kinds of reactions are fast and which kinds of reactions are slower it but the tickets overreaction you call families every single elementary steps mechanism must have been fast it was it was conversely for reactions you hate nobody heeds reactions because of easier than letting them sit at room temperature you need reaction you he reactions to make slow primary reactions fast reactions and solve your heating up a reaction something was slow so for example when you do array of features defecation reaction and we look at the temperature in the time they had to boil this I'm sure they would have bewildered harder ethanol had a higher boiling point but it's the boiling point of the and it's still slow 12 hours so the the conditions for a while for making investors I'm not going to draw the mechanism for this fisheries verification people should have learned that beckons OPM organic chemistry all 6 elementary steps what this tells you the fact that they had to heat this is that at least 1 of the steps the energy steps in the mechanism was slow at least 1 of the steps and that and the mechanism was slow and you don't know which 1 but at least 1 was slow and usually can make a guess as to which of the elementary steps was the slow step in reaction focus so the important point is from now on if you
haven't been already you cannot be satisfied simply with yields I expect you from now want to look at temperatures sometimes
they haven't time here 1 but usually you don't call reactions to minus 70 and let them go for 4 decades it's very convenient call reaction to Monday's 73 take less than a day or so from now on I want you to pay attention to temperatures in times because they're telling you about whether the elementary steps in the mechanism of faster slower than you need to keep that information back Vermont OK so finally on them when we come back on Friday we're going to start doing some pushing yes this
2 reasons so there may be side reactions that occur and to maybe temperature can affect on the ratios of side reactions on 6 0
and if things start over he list in this case things will go very badly so taking intent required can cause problems if you allow them to have to generate interim payments so usually means there too fast neutron earlier tried to get selected OK so Friday's final borders are talking about some reactions and another background stuff and will begin was cobbled Colorado and stuff in Samarra pushing


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