Hydrolysis of Phenyl Benzoate, Preparation of Cyclohexanol from Cyclohexene - Essay Example

? Hydrolysis of Phenyl Benzoate, Preparation of Cyclohexanol from Cyclohexene and Diels-Alder reaction of Maleic anhydride with Cyclopentadiene Institution Experiment 1: Hydrolysis of Phenyl Benzoate Yield of Phenol: Weight = 52 g %Yield = 55% Yield of Benzoic acid: Weight = 0.798g %Yield = 65% Response to question 1. When the crude product is acidified and re-basified to give out phenol, a base-catalytic reaction is involved. This reaction is often referred to as the acid-catalytic reaction (Borths, 2006). As widely cited, the hydrolysis of esters could be catalysed either through a base or through an acid. Notably, all these reactions are often reversible. Considering the catalysis of a base, any form of a carboxylic acid that is provided always have a reaction alongside the hydroxide, which provides an anion, as well as the acid commonly referred to as RCCO- (Damgaard, 2006). An acid can be established through the first reaction, with an extension of the second reaction. In the second stage, all the ester is changed into products of hydrolysis making the base base-catalysed reaction to being somewhat more efficient than an acid-catalysed reaction. There are certain solutes for instance gases that can be moved into another phase that forms an initial phase but without undergoing a chemical reaction (Smith, 2011). During the extraction of a solvent, two liquids that are immiscible are often mixed. This way, solutes characteristically relatively polar than others dissolves preferentially within a solvent that is somewhat more polar, while the solutes whose properties is such that they are less polar dissolves in the solvents that are less polar. For other solutes that at the initial stage light may tend to undergo a reaction during the extraction process though, it does not have a distribution ratio that can be proved to be is concentration independent. Response to question 2. Liquid-liquid extraction, also referred to as the solvent extraction or rather the partitioning is a process that involves separating compounds depending to their relative solubility’s of the compounds in two immiscible solvents. This particularly happens for organic solvents, as well as water. This method involves a substance extraction from one phase liquid to another phase liquid. As widely cited, solvent extraction or liquid-liquid extraction is a fundamental technique that finds application in the chemical laboratories where it is accomplished with the use of a separating funnel. This process is done following a chemical reaction as a constituent of the work up. In this context, the term partitioning involves the basic chemical and physical processes used in the liquid-liquid extraction. According to Damgaard (2006) solvent extraction may be taken to imply the substance separation from a mixture through the process of dissolving the given substance into a solvent. This implies that, for solubility purposes, the compounds deem soluble can be separated from the compounds that are insoluble. The partition coefficient or the distribution coefficient, on the other hand, refers often equal to the solute concentration in a phase that which is organic in nature when divided by the amount of its concentration in another phase, in aqueous form. As often is the case, the partition frequency is expressed in the form of logarithms (Zimmerman, 2006). However, in this experiment, it was not found to be necessary to calculate the partition coefficient for the extraction. This was because the two immiscible liquids were shaken together considering that the non-polar halogens do dissolve in non-polar solvents. Experiment 2: Preparation of Cyclohexanol from Cyclohexene Yield of Cyclohexanol: Weight = 3.6175 , %Yield = 106.7% , Boiling point = 82.9 0c . Response to question 1. In the IR spectrum of cyclohexanol, all motions could be described in the form of two categories of molecular vibrations (Kagan, 2002). In this case, a stretch is one of the forms of vibration which gives out some change in terms of bond length. It is a movement that is more often than not considered as rhythmical given its passing through atoms so that the distance interatomic is decreasing or increasing. A bend is another type of vibration that leads to a change in the bond angle. These are normally referred to as the wig wig motions or the scissoring rocking. The two vibrations are known to have variations. A bend could happen out or in a plane of a molecule. In this case, it could be like blades of a scissor, scissoring, or rocking whenever the two atoms shift in the similar direction (Borths, 2006). Considering the displayed IR spectrum, different bending and stretching vibrations could be seen (Wasserman, 2005). The arrow displays the motion direction. A stretching motion would need increased energy than a bending motion. The CH band stretch is strong where as that for the CH bend would be medium. An alkane, hexane (C6H10) produces an IR spectrum with few bands since the CH bonds are the only bonds that would stretch or bend. At about 3400cm-1, bands for the CH were observed. A CH2 bend band would be seen at about 2800 cm-1and where as the CH3 bend would be seen at approximately 1400 cm-1. This spectrum clearly highlights that the shapes of the bands could differ. This is displayed in diagram 1. Diagram 1. The IR spectrum for a molecule involves a display of the graph that displays the IR radiation frequencies that have been absorbed and the percentage of the incident light which goes through a molecule without getting absorption (Diels, 2008). The IR spectrum is identified by two regions. These regions include the fingerprint and functional group sections. The fingerprint region is always unique for any molecule whereas the functional group region appears to be similar for those molecules having a similar functional group. Despite the fact that an IR spectrum holds the traits for the whole molecule, there are some atomic groups in a molecule which give rise to the band absorption near or at some wave number, (v). The characteristics of the bands, therefore, enables one to identify key structure and features of the molecule after a fast IR inspection, and utilize a table of correlation. A table of correlation is a functional listing of groups and their absorption frequencies characteristics (Diels, 2008). Whenever a molecule is complicated, there may be a possibility of many fundamental vibrations, which may not be observed. Other motions may fail to alter the dipole moment for that molecule and some resemble so much that they may coincide in one band. Response to question 2. Hydroboration do results into an anti-Markovnikov addition because, in this addition, the hydroxyl group is normally attached to the carbon that is less substituted than the other carbons. In this reaction, the double bond has a net added water. To start with, borane is added to the double bond, moving a unit hydrogen to an adjacent carbon from itself. In this case, the hydroboration has a repetition of two times to the extent that about three alkene to all the borane. The trialkylborane obtained goes through a hydrogen peroxide treatment in the following step. The process interchanges the B-C bonds with that of HO-C bonding. The fact that the boron group is replaced by a group of hydroxyl shows out that the hydroboration enhances regioselectivity hence proceeding into an antimarkovnikov path. On the other hand, the electrophilic additions to alkenes result in Markovnikov addition. A Markovnikov addition is always according to the Markovnikov rule. Markovnokov’s Rule is a common rule that is often used in describing the results of most addition reactions in organic chemistry. This rule was formulated in 1870 by a Russian scientist named Viadimir Vasilevich Markovnikov. The rule states that whenever a protic acid (HX) is added to an alkene, the hydrogen acid (H) becomes attached to the carbon that has minimum alkyl substituent, whereas the halide (X) group becomes attached to the carbon with increased alkyl substituent (Olea-Serrano, 2006). This clearly implies that the atom of hydrogen is added to the carbon possessing a high number of atoms of hydrogen, with the x component being added to the carbon atom with a minimal number of atoms of hydrogen. This is practically true considering a case in which an alkene is meant to react with water in the addition reaction with alcohol that involves the carbocations formation as the ultimate result. Arguably, the group of hydroxyl (OH) combines with the atom of carbon with the highest amount of carbon-carbon bonds, with the hydrogen bonding to the carbon possessing high carbon-hydrogen bonds. Certainly, it is apparent that, for Markovnikov Rule, the chemical basis is the establishment of a carbocation often considered most stable during the process of addition. As widely cited, the hydrogen ion addition to a unit atom of carbon within the alkene establishes a charge that is positive on another carbon forming an intermediate carbocation. With increasing substitution of the carbocation, the bonding of carbon or the substituent electron donation increases. This results into an intermediate carbon, which is somewhat stable especially with the inclusion of hyper conjugation and induction. What this means is that the component of the reaction of addition is a product that is made from an intermediate considered most stable (Longuet-Higgins, 2005). In this case, one key product of HX addition to an alkene contains an atom of hydrogen in a position of minimal substitution whereas X is in a position that can easily be substituted. The less stable, less substituted carbocation will eventually be established to a certain degree and will end up establishing a product that is minor with the X attachment on the opposite side. In this respect, the electrophilic additions to alkenes result in Markovnikov addition since in this reaction the carbocation stability difference could be accounted for through the effects of electron-donating of the group of an extra methyl on the other part of the double bond. In this reaction, the carbon that is more substituted finally attaches or bonds towards the acid’s heteroatom, where as the carbon that is less substituted is protonated (Geerlings, 2012). This is generally referred to as the Markovnikov’s rule. Response to question 3. Experiment 3: Diels-Alder reaction of Maleic anhydride with Cyclopentadiene Yield of Maleic anhydride-Cyclopentadiene adduct: Weight = 0.59g %Yield = 53% Response to question 1. A Diels-Alder reaction involves a chemical reaction that organic in nature for instance the cycloaddition often common in between a diene conjugated, along with an alkene that is substituted mostly referred the dienophile to establish a cyclohexene that is substituted (Olea-Serrano, 2006). This reaction could proceed despite the fact that the atoms in a ring considered being newly formed may have no carbon (Longuet-Higgins, 2005). The four features of a Diels-Alder reaction are the fact that these reactions are thermal, the reactions come up with new rings that are six-membered; the reaction has three bonds ? bond breaks and two C-C ? bonds that are new and one C-C ? bonds; the reaction involves a bond break which establishes a unit step. This reaction is normally described as 4?s + 2?s, where 4?s is known as the diene, and 2?s is referred to as the dienophile (Hein, 2006). A diene part inside the Diels-Alder reaction could be cyclic or open-chain, and it could have a number of substituents. It is known to have only a unit limitation. This implies that it has to belong to the S-cis conformation (MacGillivray, 2005). The butadiene does prefers the conformation of s-trans having the two double bonds far away from others. Whenever there are larger substituents than hydrogen, the steric hindrances could affect the conformations of the relative stabilities. Cyclic dienes considered being permanent in the s-cis conformation are known to be reactive exceptionally, where as those cyclic dienes considered being in the s-trans permanently cannot adopt the s-cis conformation will not go through the reaction of diels-Alder (Kosata, 2006). On the other hand, the dienophile part of the diels-Alder reaction posses an electron that withdraws the conjugated group to the alkene (Movassaghi, 2007). Despite being common, this trait may not be exclusive of the dienophiles of the diels-Alder. This component could be activated through a Lewis acid like the pentachloride niobium (MacGillivray, 2005). Response to question 2. P orbital or the ? orbitals are bonds that are covalent in which two lobes of a unit atomic orbital overlaps the two lobes of another atomic orbital. All these orbitals do share a plane that is nodal which goes through the nuclei that are involved (Smith, 2011). The P orbitals take part in the pi bonding forming the key for the metal-metal multiple bonding. In a cycloaddition reaction, two compound having ? bonds react to establish a cyclic product having two new bonds (?) (Woodward, 2005). The quantity of ? bonds that are involved, and the thermal or photochemical conditions for a reaction to occurring, are the features that determine the direction of the reaction. The main function of the p orbitals is to overlap on the adjacent carbon (Wasserman, 2005). The p orbital combine in many ways forming other orbitals. Cycloaddition reactions considered as thermal are known to have reactants in an electronic ground state. These reactions have a (4n + 2) ? electrons taking part in the initial materials for a certain integer n. The reaction happen for orbital symmetry, antarafacial-antarafacial, or in the suprafacial-suprafacial way. The cycloaddition reaction occurs in either thermal or photochemical. In the thermal conditions, the even ? bonds form a conrotatory thermal reaction whereas the odd ? bonds form a disrotatory thermal reaction (Kosata, 2006). Under photochemical reactions, the even ? bonds form a disrotatory photochemical reaction, whereas the odd ? bonds form a Conrotatory photochemical reaction. Response to question 3. References. Borths, C., 2006. New Strategy for Organic Catalyst: Organo-catalytic Diels?Alder Reaction. J of the American Chem Socie 122 (17): 4243. Damgaard, I., 2006. Persistent Pesticides in Human Breasts Milk and Cryptorchidism. Environmental Health Perspective, 114: pp. 1133–1138. Diels, O., 2008. Synthesis in der hydroaromatischens Reihe. Chemie der Annalen 460: 98–122. Geerlings, A., 2012. Woodward-Hoffmann Rule Reinterpreted by Conceptual Density Functional Theory. Accounts of Chemical Research, 45(5); 683-695. Hein, S., 2006. Exploration of Photochemical Pericycle Reactions of NMR Data. J of Chemical Educ 83 (6): 940–942. Kagan, H., 2002. Catalyst asymmetric Diel Alder reaction. Oxford: Oxford University press. Kosata, B., 2006. Cycloaddition. New York: Jack and sons press. Lehman, J., 2001. Operational organic Chemistry. Oxford: Oxford University press. Longuet-Higgins, A., 2005. Electronic Mechanism of Electrocyclic Reaction. Journal of . American. Chem. Soc. 87(9); 2045-2046. MacGillivray, L., 2005. Supramolecular Reactivity in a Solid State by Linear Molecular Templates. Journal of American. Chem. Soc. 122 (32): 7817–7818. Movassaghi, M., 2007. Stereoselective Intermolecular [3+3] Cycloaddition Reactions of Cyclic Enamine and Enone. Angews Chemistry International Educ. 46 (4): 565–568. Olea-Serrano, J., 2006. Environment and Lifestyle Factor for Organochloride Exposure in Women Living in Southern Spain. Chemosphere 62: pp. 1917–1924. Smith, J., 2011. Diels-Alder Reactions in Organic Chemistry. New York, NY: McGraw-Hill. Wasserman, A.,2005. Diels–Alder Reactions. New York: Elsevier Company. Woodward, R., 2005. Stereochemistry of Electrocyclic Reaction. Journal of American Chem. Soc, 87(2); 395-397. Zimmerman, H., 2006. Organic photochemistry. 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