...Nucleophilic Carbon-Formation and Reaction of a Grignard Reaction 03/03/2014 Nucleophilic Carbon-Formation and reaction of a Grignard reagent Abstract: In this experiment, phenyl benzoate was made in order to react it with methyl benzoate in order to produce the compound triphenylmethanol via a grignard reaction. There was a 37.2% yield of triphenylmethanol, and the melting point obtained was 161-163°C. Introduction: Grignard reagents are usually formed when alkyl halides and magnesium react together. The carbon and magnesium have a very large difference in electronegativity. This allows the carbon to withdraw the electron density from magnesium through the process of induction.1 Grignard reagents are related to organolithium reagents which are useful and contain carbon atoms that are strongly nucleophilic. They react with a range of carbonyl compounds to make new carbon-carbon bonds. In this lab, phenyl magnesium bromide will be reacted with methyl benzoate to obtain triphenylmethanol which is a grignard reaction. Mechanism: Experiment: Place 0.5g of crushed magnesium turnings into 50 mL round bottom flask; add the stir bar, and 5mL of anhydrous ether. Construct an apparatus for slow addition of reagents and also so the reaction can go into reflux. Make up a solution of 2.4mL of bromobenzene in 5mL of anhydrous ether in a dry flask then add it to the separatory funnel. Add about 0.5mL of bromobenzene of the bromobenzene solution to the mixture of magnesium...
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...A Grignard-Like Organic Reaction The Synthesis of 1-phenyl-3-buten-1-ol Introduction The Grignard reaction is an important synthetic process by which a new carbon to carbon bond is formed. Magnesium metal is first reacted with an organic halide forming the Grignard reagent. The Grignard reaction is the addition of an organomagnesium halide (Grignard reagent) to a ketone or aldehyde, to form a tertiary or secondary alcohol, respectively. For example, the reaction with formaldehyde leads to a primary alcohol. Grignard Reagents are also used in the following important reactions: The addition of an excess of a Grignard reagent to an ester or lactone gives a tertiary alcohol in which two alkyl groups are the same, and the addition of a Grignard reagent to a nitrile produces an unsymmetrical ketone via a metalloimine intermediate. A sample Grignard reaction mechanism can be seen in Figure 1 of a Grignard reagent being prepared with an alkyl bromide and later reacted with a formaldehyde to produce a primary alcohol. The purpose of this lab was to form 1-phenyl-3-buten-1-ol using a Grignard reaction. The Grignard reactant was produced from Zinc and Allyl Bromide which was then reacted to Benzaldehyde. The formation of the final product will be confirmed using a Thin Layer Chromatography, TLC, of the product and Benzaldehyde and an IR analysis of the product. Abstract In reactions involving Grignard reagents, it is important to exclude water and air, which rapidly destroy...
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...Preparation of Grignard Reagents and the Preparation of 2-methyl-3-heptanol from 2-methylpropanal and Grignard Reagents II. Introduction Organometallic compounds are substances with a carbon-metal bond (structure 1); these metals may be Li, Na, Mg, Cu, Hg, Pd, or any other transition metal (Gilbert, Martin 639). Organometallic compounds with M representing MgBr are organomagnesium compounds, or more commonly Grignard reagents. Grignard reagents are unique due to their polarization. The carbon atom in the Grignard reagent is made electron-rich by the electropositive metal giving the carbon atom a partial negative charge (δ-), and the metal a partial positive charge (δ+). This unique charge distribution allows carbon to act as a nucleophile in chemical reactions. However, when carbon is bonded to a more electronegative atom, such as a halogen (structure 2) or to oxygen (structure 3), it acts as an electrophile in chemical reactions (Gilbert, Martin 639). Figure 1. Structure of an organometallic reagent (structure 1), an alkyl halide (structure 2), and a carbonyl compound (structure 3). * Due to the nucleophilic properties, organometallic compounds are commonly used in reactions to form new carbon-carbon bonds. Equation 1 is a general example of a reaction between an alkyl halide and an organometallic compound. Equation 2 is an example of a reaction of a carbonyl and an organometallic compound. In both reactions the nucleophilic carbon atom of the organometallic...
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...In this experiment, a Grignard was performed with 3-pentanone and an unknown alkyl bromide to obtain and identify a 3˚ alcohol. In order to identify the alkyl bromide, the identity of the product was found by spectroscopic analysis. To complete this reaction, first the Grignard reagent was prepared. The reagent was generated by taking Unknown AP and adding it, dropwise, to a mixture of 6.2 mL of THF and 1.0008 g of magnesium. The magnesium had to be crushed to initiate the reaction between magnesium and alkyl bromide. Once the reaction took place, the colorless solution became cloudy and white bubbles formed. Eventually, the solution turned black-brown in color. This solution was stirred for 20 minutes until a solution of 4.0 mL in 5.4 mL of...
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...Pg(303-309/312-314) 3/11/14 Experiment #36 and 36b Preparation of the Grignard Reagent and Benzoic Acid Purpose- In this experiment we learned to prepare a Grignard reagent, phenyl magnesium bromide, which we then converted to a carboxylic acid. Procedure & Observations- First we started by setting up our apparatus for Grignard reactions. We started by making sure all glassware was completely dried as a Grignard reaction would not occur if water is present. We used a 100ml round bottom flask for our solution and placed it on a hot plate to control the heating process. We then weighed out 0.4920g of magnesium turnings and placed it into the round bottom flask. We also measured out 2.1ml of bromobenzene into a 50ml flask and got a weight of 3.0557g. We then added 10ml of ether to the 2.1ml of bromobenzene and pipetted half into the round bottom flask. The other half was then added to the separatory funnel along with an additional 7ml of ether. From here we began heating the mixture until boiling started to occur. Once the reaction started to begin we got an instant brownish color change. We also ended up using a drop from another group’s reaction to help move along the process. Once this happened we began slowly adding the remaining bromobenzene over a five minute period. Once it had all been added we added an additional 1ml of ether to rinse the funnel. We then heated under gentle reflux till all the magnesium...
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...attribute the second one (1765 cm-' for 6a and 1760 cm-l for 6b) to the amide carbonyl. These abnormal high values for an amide band reveal, in accordance with Bredt's rule, an important inhibition of the N-C=O resonance in these N-bridgehead lactams." On the other hand, ' NMR spectra of the crude maH terials obtained from diesters 4c,d at 390-400 "C showed the characteristic signals of a terminal vinyl group suggesting that an elimination reaction follows or competes with the [1,4] migration. Flash column chromatography of the mixture resulting from the thermolysis of the piperidine derivative 4c afforded besides the pyrazolinone 6c12an isomeric N-alkenyl compound whose spectroscopic datal3support the hydroxy-bpyrazole structure 7c. The analogous elimination product 7d formed in lower yield (15% estimation on the basis of 'H NMR spectra) could not be isolated. Pyrazolinone 6c submitted to flow pyrolysis at 400 O C was recovered unchanged. Thus hydroxy-bpyrazoles 7c,d result from an intramolecular elimination reaction of ylides 5c,d (Scheme 111),either by a six-center mechanism involving the negative charge delocalized on the carbonyl oxygen (path a) or by a Cope-type elimination14 (path b) and subsequent isomerization (8 7) to the stable tautomer in aprotic media.ls We believe that the elimination takes place according to the latter pathway since crystallographic analyses of analogous ylidic...
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...Experiment: Grignard Synthesis of Triphenymethanol Title References: Rosenberg, Robert. (2010). Experimental Organic Chemistry: Howard University Edition. Virginia Beach, VA: Acedemx Publishing Services, Inc. McMurry, John. (2008). Organic Chemistry, 7th Edition. Mason, Ohio: Cengage Learning. Syntheses of triphenylmethanol using the Grignard reagent Phenylmagnesium bromide Abstract A Grignard reaction was demonstrated in order to produce triphenylmethanol from the use of the reagents bromobenzene and phenylmagnesium bromide. This was accomplished by first creating the Grignard Reagent (phenylmagnesium bromide). To do this refluxing of bromobenzene with magnesium and anhydrous ether was done. The Grignard reagent produced was placed in a round bottom flask. Next, a solution of methyl benzoate and ether was slowly mixed into the flask while refluxing was being performed. Upon completion of the reaction, the crystals were isolated using ligroin and vacuum filtration. Analysis of the IR spectra and melting point supported these results. The significance of these findings shows how thoroughly the experiment was carried out. Introduction The Grignard reagent can easily be formed by the reaction of an alkyl halide, in this case bromine, with magnesium metal, in anhydrous diethyl ether. The reaction takes place at the surface of the metal, and the ether plays the role as both the reactant and the solvent. As a result, the Grignard reagent is produced at the surface...
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...into an alcohol using a Grignard reagent. The reagents used were Mg and Bromobenzene to first create the Grignard reagent, and then Acetophenone was added to synthesize an alcohol. In preparation of the Grignard reagent, the Mg and Bromobenzene solution turned the proper brown color after being initiated and refluxed, indicating a Grignard has been made. Then, Acetophenone was added to the solution and heated in a sand bath and refluxed. 3.0M HCl was added and during this addition, the solution bubbled into the water condenser. NaHCO3 and NaCl were added to extract the aqueous layer to remove the organic layer to recover product. The Grignard reaction yielded 1, 1-Diphenylethanol as the product. This was determined by the nature of how Grignard reagents add and...
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...concluded that the Grignard reaction did not happen, and the diphenylmethanol was not formed. This experiment was not successful mainly because no Grignard reagent or tiny amount of Grignard reagent was produced or active prior to addition of benzaldehyde. By the end of the lab, only berry-redish solution was produced without any solid, this is a physical evidence of not producing any diphenylmethanol, because diphenylmethanol is white crystal. Also, after adding bromobenzene, it was barely seen bubbling in the flask; however, there was supposed to have a lively reflux in the flash as a consequence of the exothermic reaction; hence, no Grignard reagent was expected to be produced. These physical observations are aligned with IR spectroscopy analysis. The presence of a peak at 1706.06 cm-1 indicates the presence of carbonyl group, (in this case, benzaldehyde) Peaks at 3065.46, 2959.13, 2927.61 cm-1 were likely to be aromatic C-H stretches. To the right of the aromatic C-H stretches, it was appeared a shoulder-type peak at 2872.07 and 2732.33 cm-1, which proves the presence of aldehyde group. In the IR graph, a very weak peak at 3396.06 cm-1 can be found. It falls in the alcohol group range, but it is very weak. Considering the actual lab situation, it is more likely to be the water group. The NMR graph doesn’t support this specific lab result since it is from another sample. This specific NMR result indicates a successful experiment, a fairly complete reaction with producing diphenylmethanol...
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...Chem‐106 Grignard Synthesis of Triphenylmethanol Objective: The purpose of this experiment is to synthesize triphenylmethanol from benzophenone via Grignard reaction. The product will be isolated through extractions and purified by recrystallization. Reaction efficiency will be evaluated through percent yield, percent recovery, and the purity of the final product will be determined by IR, TLC, and mp determination. Chemicals: bromobenzene, magnesium turnings, diethyl ether, benzophenone, biphenyl, triphenylmethanol, iodine, 6 M HCl, brine, anhydrous MgSO4 or Na2SO4, 10:90 EtOAc/hexanes. Glassware and equipment: 100 mL RBF, air condenser, Claisen adaptor, 60 and 125 mL addition funnel, short stem glass funnel, two 50 mL Erlenmeyer flasks, 10 mL graduated cylinder, lab jack, crystallizing dish, magnetic stir bar. Techniques: reflux, extraction, vacuum filtration, recrystallization, TLC, mp, IR spectroscopy. Introduction In 1912 Victor Grignard received the Nobel prize in chemistry for his work on the reaction that bears his name, a carbon-carbon bond-forming reaction by which almost any alcohol may be formed from appropriate alkyl halides and carbonyl compounds. The Grignard reagent RMgBr is easily formed by redox reaction of an alkyl halide with magnesium metal in anhydrous diethyl ether solvent. R-Br + Mg → RMgBr The Grignard reagent can be viewed as an ionic species consisting of carbanion R-, with Mg2+ counterion and an additional Br- counterion. The carbanion...
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...An Aldol Condensation Reaction: The Synthesis of Tetraphenylcyclopentadienone—An Example of a Double-Crossed Aldol Addition Reactions of Carbonyl Groups The chemical reactivity of aldehydes and ketones is closely associated with the presence of the carbonyl group in their structures. For example, both aldehydes and ketones undergo addition reactions such as the addition of a Grignard reagent to the carbonyl group as shown in Figure 1. Figure 1. Addition reactions. The reactions in Figure 1 differ only because the pink H of an aldehyde is replaced by R′′ in the ketone. The addition reaction occurs at the carbonyl group. The carbonyl group is polarized so that the carbon atom bears a partial positive charge and the oxygen atom bears a partial negative charge. The R′ group of the Grignard reagent is negative relative to the positive Mg atom. Thus, the negative R′ group bonds to the positive carbon atom, and the negative oxygen and metallic magnesium form an ionic bond, yielding a salt in each reaction. The addition product is acidified in each case to make a covalent alcohol. The aldehyde produces a IIo alcohol; whereas, the ketone produces a IIIo alcohol owing to the R′′ group. The two equations for addition reactions in Figure 1 are summarized in Figure 2. A nucleophile (negative species) bonds to the carbonyl carbon (positive), breaking the π bond of the carbonyl group. Figure 2. Addition of a nucleophile to a carbonyl group. Figure 2 focuses our...
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...CH 220C ORGANIC CHEMISTRY LABORATORY Spring, 2015 Section Page 1. General Information 2 2. Safety Information 2 3. Attendance 3 Make-Up Policy 3 4. Laboratory Protocol 3 Assigned Reading 3 Pre-Lab Quizzes 3 Lab Notebook 5 Chemicals 5 Due Dates for Reports 5 5. Orientation 5 In-Lab Information 5 Library Information 5 6. Check-In 6 7. Grading Procedure 6 8. Policy on Cheating 7 9. TA Office Hours 8 10. Faculty Course CoordinatorS 8 11. Course Web Page 8 12. Hints to Minimize Frustration IN ORGANIC CHEMISTRY 8 13. Work Schedule 10 Lab Report Due Date Schedule 10 Experiments 10 14. Supplements 17 A. Extraction of Unknown 17 B. Recrystallization of Unknown Products 18 C. Methyl Benzoate 19 D. Synthesis of Luminol 20 E. Azo Violet 23 1. GENERAL INFORMATION PRE- and CO-REQUISITES Pre- and co-requisites for CH 220C listed in the Course Schedule. Important: Because the lecture and laboratory courses are co-requisites of each other, dropping one of them requires that you drop the other as well, unless the drop occurs during ...
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...Pentachlorophenol (PCP) in wood treatment 1.Introduction Wood is a hard, fibrous structural tissue found in the stems and roots of trees and other woody plants. It has been used for thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers (which are strong in tension) embedded in a matrix of lignin which resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees or it is defined more broadly to include the same type of tissue elsewhere such as in the roots of trees or shrubs. In a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves. It also mediates the transfer of water and nutrients to the leaves and other growing tissues. Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, or wood chips or fiber. The Earth contains about one trillion tonnes of wood, which grows at a rate of 10 billion tonnes per year. As an abundant, carbon-neutral renewable resource, woody materials have been of intense interest as a source of renewable energy. In 1991, approximately 3.5 billion cubic meters of wood were harvested. Dominant uses were for furniture and building construction. The wood-preserving industry treats lumber with various chemicals to protect against insect damage and decay. Chemically preserved wood is used in products for outdoor use such as railway ties...
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