Q: Show how you would convert oleic acid to the following fatty acid derivatives. Please resubmit the question and s Q: n the laboratory a student combines Q: Part B If you have 5. A: From the given reaction it is clear that two mole of hydrogen reacts with one mole of oxygen to form Operations Management. Chemical Engineering. Civil Engineering. Computer Engineering. Computer Science. Electrical Engineering. Mechanical Engineering. Advanced Math.
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Tagged in. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic particles, and in everyday as well as scientific usage, "matter" generally includes atoms and anything made up of them, and any particles and objects that act as if they have both rest mass and volume. However it does not include massless particles such as photons, or other energy phenomena or waves such as light or sound.
Matter exists in various states known as phases that are defined by various physical properties, such as state of matter, phase, shape, and density. The Standard Model of particle physics and the general theory of relativity describe fundamental particles and the fundamental forces acting between them that control the structure and dynamics of matter.
Click 'Join' if it's correct. Joann G. Chemistry 1 week, 4 days ago. View Full Video Already have an account? Narayan H. Discussion You must be signed in to discuss. Upgrade today to get a personal Numerade Expert Educator answer! Ask unlimited questions. Test yourself. Join Study Groups. Create your own study plan. Join live cram sessions. Brown Purdue, Nobel Prize discovered that the solvated monomer adds rapidly under mild conditions.
Boron and hydrogen have rather similar electronegativities, with hydrogen being slightly greater, so it is not likely there is significant dipolar character to the B-H bond. Since boron is electron deficient it does not have a valence shell electron octet the reagent itself is a Lewis acid and can bond to the pi-electrons of a double bond by displacement of the ether moiety from the solvated monomer. As shown in the following equation, this bonding might generate a dipolar intermediate consisting of a negatively-charged boron and a carbocation.
Such a species would not be stable and would rearrange to a neutral product by the shift of a hydride to the carbocation center. Indeed, this hydride shift is believed to occur concurrently with the initial bonding to boron, as shown by the transition state drawn below the equation, so the discrete intermediate shown in the equation is not actually formed.
Nevertheless, the carbocation stability rule cited above remains a useful way to predict the products from hydroboration reactions. You may correct the top equation by clicking the button on its right. Note that this addition is unique among those we have discussed, in that it is a single-step process. Also, all three hydrogens in borane are potentially reactive, so that the alkyl borane product from the first addition may serve as the hydroboration reagent for two additional alkene molecules.
To examine models of B 2 H 6. As illustrated in the drawing on the right, the pi-bond fixes the carbon-carbon double bond in a planar configuration, and does not permit free rotation about the double bond itself.
We see then that addition reactions to this function might occur in three different ways, depending on the relative orientation of the atoms or groups that add to the carbons of the double bond: i they may bond from the same side, ii they may bond from opposite sides, or iii they may bond randomly from both sides.
The first two possibilities are examples of stereoselectivity , the first being termed syn-addition , and the second anti-addition. Since initial electrophilic attack on the double bond may occur equally well from either side, it is in the second step or stage of the reaction bonding of the nucleophile that stereoselectivity may be imposed.
If the two-step mechanism described above is correct, and if the carbocation intermediate is sufficiently long-lived to freely-rotate about the sigma-bond component of the original double bond, we would expect to find random or non-stereoselective addition in the products.
On the other hand, if the intermediate is short-lived and factors such as steric hindrance or neighboring group interactions favor one side in the second step, then stereoselectivity in product formation is likely. The interesting differences in stereoselectivity noted here provide further insight into the mechanisms of these addition reactions. The selectivity is often anti, but reports of syn selectivity and non-selectivity are not uncommon. Such reactions are most prone to rearrangement when this is favored by the alkene structure.
The halogens chlorine and bromine add rapidly to a wide variety of alkenes without inducing the kinds of structural rearrangements noted for strong acids first example below. The stereoselectivity of these additions is strongly anti , as shown in many of the following examples. An important principle should be restated at this time.
The alkenes shown here are all achiral, but the addition products have chiral centers, and in many cases may exist as enantiomeric stereoisomers. In the absence of chiral catalysts or reagents, reactions of this kind will always give racemic mixtures if the products are enantiomeric.
On the other hand, if two chiral centers are formed in the addition the reaction will be diastereomer selective. This is clearly shown by the addition of bromine to the isomeric 2-butenes. Anti-addition to cisbutene gives the racemic product, whereas anti-addition to the trans-isomer gives the meso-diastereomer. We can account both for the high stereoselectivity and the lack of rearrangement in these reactions by proposing a stabilizing interaction between the developing carbocation center and the electron rich halogen atom on the adjacent carbon.
This interaction, which is depicted for bromine in the following equation, delocalizes the positive charge on the intermediate and blocks halide ion attack from the syn-location. The stabilization provided by this halogen-carbocation bonding makes rearrangement unlikely, and in a few cases three-membered cyclic halonium cations have been isolated and identified as true intermediates. A resonance description of such a bromonium ion intermediate is shown below.
The positive charge is delocalized over all the atoms of the ring, but should be concentrated at the more substituted carbon carbocation stability , and this is the site to which the nucleophile will bond. The stereoselectivity described here is in large part due to a stereoelectronic effect.
This aspect of addition reactions may be explored by clicking here. Because they proceed by way of polar ion-pair intermediates, chlorine and bromine addition reactions are faster in polar solvents than in non-polar solvents, such as hexane or carbon tetrachloride. However, in order to prevent solvent nucleophiles from competing with the halide anion, these non-polar solvents are often selected for these reactions.
Such reactions are sensitive to pH and other factors, so when these products are desired it is necessary to modify the addition reagent. By adding AgOH, the concentration of HOCl can be greatly increased, and the chlorohydrin addition product obtained from alkenes. The more widely used HOBr reagent, hypobromous acid, is commonly made by hydrolysis of N-bromoacetamide, as shown below.
Both HOCl and HOBr additions occur in an anti fashion, and with the regioselectivity predicted by this mechanism OH bonds to the more substituted carbon of the alkene. Vicinal halohydrins provide an alternative route for the epoxidation of alkenes over that of reaction with peracids.
As illustrated in the following diagram, a base induced intramolecular substitution reaction forms a three-membered cyclic ether called an epoxide.
Both the halohydrin formation and halide displacement reactions are stereospecific, so stereoisomerism in the alkene will be reflected in the epoxide product i. A general procedure for forming these useful compounds will be discussed in the next section. This page is the property of William Reusch. Comments, questions and errors should be sent to whreusch msu.
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