Reduction Of Cyclohexanone

Reducing Cyclohexanone: A Comprehensive Q&A

Introduction:

Cyclohexanone, a six-membered cyclic ketone, is a crucial intermediate in the synthesis of various industrial chemicals and pharmaceuticals. Its reduction to cyclohexanol, a secondary alcohol, is a fundamental transformation in organic chemistry with widespread applications. Understanding the different methods and their nuances is critical for choosing the most efficient and selective approach for a particular application. This article will explore the reduction of cyclohexanone in a question-and-answer format, addressing key aspects of this important reaction.

I. Methods for Reducing Cyclohexanone:

Q: What are the common methods used to reduce cyclohexanone to cyclohexanol?

A: Several methods exist, each offering advantages and disadvantages depending on the desired outcome and scale. Common methods include:

Catalytic Hydrogenation: This is a widely used industrial method involving the use of a metal catalyst (e.g., palladium, platinum, nickel) and hydrogen gas under pressure. It's highly efficient and provides high yields of cyclohexanol.
Hydride Reduction: This employs reducing agents like sodium borohydride (NaBH₄) or lithium aluminum hydride (LiAlH₄) in a suitable solvent. NaBH₄ is milder and selective, typically used in laboratory settings. LiAlH₄ is a more powerful reducing agent, capable of reducing a wider range of functional groups but requiring careful handling due to its reactivity with water.
Transfer Hydrogenation: This method uses a hydrogen donor molecule (e.g., isopropanol) in the presence of a catalyst, often a metal complex, to transfer hydrogen atoms to the ketone, reducing it to the alcohol. This method is environmentally friendly as it avoids using high-pressure hydrogen gas.
Bioreduction: Enzymes, particularly those from microorganisms, can catalyze the selective reduction of ketones to alcohols. This method is highly specific and environmentally benign but may have limitations in scalability and cost-effectiveness.

II. Mechanism and Selectivity:

Q: Can you explain the mechanism of hydride reduction, specifically using NaBH₄?

A: Sodium borohydride (NaBH₄) acts as a source of hydride ions (H⁻). The hydride ion attacks the electrophilic carbonyl carbon of cyclohexanone, forming a tetrahedral intermediate. Protonation of this intermediate, typically by a protic solvent like methanol or ethanol, yields cyclohexanol. The reaction proceeds with high stereoselectivity, generally yielding the less hindered alcohol isomer if the starting ketone is chiral.

Q: How does the choice of reducing agent affect the selectivity of the reaction?

A: The choice of reducing agent significantly influences the selectivity of the reaction. NaBH₄ is generally less reactive and more selective than LiAlH₄. While both reduce ketones to alcohols, LiAlH₄ can also reduce esters, carboxylic acids, and other functional groups present in the molecule. This makes NaBH₄ preferable when dealing with complex molecules containing other reducible groups. Catalytic hydrogenation also tends to be highly selective for ketones, but its selectivity can depend on the catalyst and reaction conditions.

III. Reaction Conditions and Optimization:

Q: What factors influence the reaction rate and yield of cyclohexanone reduction?

A: Several factors influence the reaction:

Temperature: Higher temperatures generally increase the reaction rate, but excessive heat can lead to side reactions or decomposition of the reducing agent.
Solvent: The choice of solvent affects the solubility of the reactants and the reaction rate. Polar protic solvents are often preferred for hydride reductions.
Concentration: The concentration of reactants can influence the reaction rate and yield.
Catalyst (for hydrogenation): The type and amount of catalyst, as well as its surface area, significantly impact the hydrogenation reaction rate.
Pressure (for hydrogenation): Higher hydrogen pressures generally increase the reaction rate in catalytic hydrogenation.

IV. Real-World Applications:

Q: What are some real-world applications of cyclohexanol, the product of cyclohexanone reduction?

A: Cyclohexanol is a versatile intermediate used in the production of various important chemicals, including:

Adipic acid: A key component in the production of nylon-6,6.
Caprolactam: Used in the production of nylon-6.
Cyclohexanone: Although we start with cyclohexanone, the reduction and subsequent oxidation can produce high-purity cyclohexanone.
Solvents: Cyclohexanol is used as a solvent in various industrial processes.
Plasticizers: It is employed in the production of plasticizers for polymers.

V. Conclusion:

The reduction of cyclohexanone to cyclohexanol is a crucial transformation in organic chemistry with vast industrial applications. The choice of reducing agent depends on several factors, including the desired selectivity, scale of the reaction, and the presence of other functional groups. Understanding these factors enables the selection of the optimal method for a specific application, leading to efficient and high-yielding syntheses of cyclohexanol and its derivatives.

FAQs:

1. What are the safety precautions when working with LiAlH₄? LiAlH₄ reacts violently with water, generating hydrogen gas. It must be handled under inert conditions (e.g., under nitrogen or argon atmosphere) and appropriate safety measures (gloves, eye protection) should always be employed.

2. How can I monitor the progress of the reduction reaction? Techniques like thin-layer chromatography (TLC) or gas chromatography (GC) can be used to monitor the reaction progress by tracking the disappearance of cyclohexanone and the appearance of cyclohexanol.

3. Can I use other ketones instead of cyclohexanone for similar reductions? Yes, the methods described can be applied to reduce other ketones, although the reaction conditions and yields may vary depending on the structure of the ketone.

4. What is the typical yield for the reduction of cyclohexanone using NaBH₄? Typically, yields exceeding 90% can be achieved using NaBH₄ under appropriate conditions.

5. What are the environmental considerations associated with different reduction methods? Catalytic hydrogenation can generate waste from the catalyst, while hydride reductions produce inorganic byproducts. Transfer hydrogenation and bioreduction are generally considered more environmentally friendly options.

Search Results:

Reduction of Cyclohexanone to Cyclohexanol - THEORY Reduction of Cyclohexanone to Cyclohexanol. Course 2425 - Section 33700. 08/02/ OBJECTIVE/PURPOSE. To synthesize cyclohexanol from the reduction of cyclohexanone with the use of sodium. borohydride and sodium methoxide as the catalyst. THEORY. Cyclohexanol is from reducing cyclohexanone with sodium borohydride. The ketone in

Reduction Of Cyclohexanone The reduction of cyclohexanone to cyclohexanol is a crucial transformation in organic chemistry with vast industrial applications. The choice of reducing agent depends on several factors, including the desired selectivity, scale of the reaction, and the presence of other functional groups.

A Microwave-Assisted Reduction of Cyclohexanone Using Solid … 1 Jul 2005 · We report a microwave-assisted reduction of cyclohexanone by sodium borohydride that is supported on SiO2. The reaction was completed in less than 3 minutes. Workup and analysis by GC–MS, IR, and 1H NMR was possible in a two and half-hour laboratory session.

Origin of π-facial stereoselectivity of hydride reduction of ... 7 Jul 1997 · A new theoretical interpretation for π-facial stereoselectivity of hydride reduction of cyclohexanones has been proposed based on the simple assumption that the lowest unoccupied molecular orbital (LUMO) of the substrates should play an essential role in the reaction: π-Facial stereoselectivity is described by relative magnitude of e xterior f r...

SODIUM BOROHYDRIDE REDUCTION OF CYCLOHEXANONE … To synthesize cyclohexanol from the reduction of cyclohexanone using sodium borohydride. To characterize the reduction product using IR spectroscopy. INTRODUCTION Aldehydes and ketones have carbonyl group which plays an important role in determining the chemistry of these functional groups.

Quantitative prediction of stereochemistry in the reduction of ... An extremely simple method is presented for quantitatively predicting the stereochemical product ratio in the reduction of alkylcyclohexanones by sodium borohydride. Accurate predictions are made except in the cases of highly hindered ketones.

Reduction of cyclohexanone: predicting the stereochemistry of the ... Interpreting the preference of nucleohilic attack on the carbonyl carbon of substituted cyclohexanes. A molecular orbital approach that every one can underst...

The Wolff-Kishner, Clemmensen, And Other Carbonyl Reductions 27 Aug 2018 · The Wolff Kishner reduction of ketones utilizes hydrazine (NH 2 NH 2) as the reducing agent in the presence of strong base (KOH) in a high-boiling protic solvent (ethylene glycol, HO-CH 2 CH 2-OH, boiling point 197 °C).

Cyclohexanone - SpringerLink 2 Jan 2023 · This is illustrated with an example of the sodium borohydride reduction of an anancomeric cyclohexanone like 4-t-butylcyclohexanone through the transition state (A) in Fig. 8.5, which energetically resembles the product trans-alcohol.

SODIUM BOROHYDRIDE REDUCTION OF CYCLOHEXANONE … To synthesize cyclohexanol from the reduction of cyclohexanone using sodium borohydride. To characterize the reduction product using IR spectroscopy. INTRODUCTION Aldehydes and ketones have carbonyl group which plays an important role in determining the chemistry of these functional groups.

Sodium Borohydride Reduction of Cyclohexanone. - Academia.edu The reaction offers wide applicability for the selective carboxylic group reduction methodology. The chemoselective reduction was demonstrated by the reduction of Fenofibric acid, an active metabolite of the drug Fenofibrate, to corresponding alcohol in …

CHM557 EXP 2 - SODIUM BOROHYDRIDE REDUCTION OF CYCLOHEXANONE The purpose of this experiment is to perform a reduction reaction to generate an alcohol from a ketone. The specific reaction involves reducing cyclohexanone with sodium borohydride, filtering and drying the cyclohexanol product, and taking an IR spectrum of the product to characterize it.

Cerium(III) Chloride-Mediated Stereoselective Reduction of a 4 ... 3 Dec 2019 · It was found that the addition of sub-stoichiometric cerium (III) chloride in conjunction with sodium borohydride provided the desired trans-cyclohexanol (arising out of axial delivery of the hydride onto the carbonyl) in >16:1 selectivity and excellent conversion.

Experiment 2 Sodium Borohydride Reduction of Cyclohexanone In this experiment, using sodium borohydride to reduce from a ketone (cyclohexanone) to a secondary alcohol (cyclohexanol) along with methanol, sodium hydroxide, and water. Sodium borohydride is a mild reducing agent and the reaction are carried out in …

A Benchmark of Density Functional Approximations For Thermochemistry ... 26 Jun 2019 · Based on an extensive benchmark study, we present a two-fold computational recipe able to perfectly reproduce and interpret our experimental data for the reduction of 2-substituted cyclohexanones with LiAlH 4.

Reduction of cyclohexanone 1 m with NaBH 4 . a - ResearchGate Various aldehydes and ketones were treated with a stoichiometric amount of NaBH4 by the addition of a small amount of MeOH or EtOH to give the corresponding alcohols in excellent yields. The...

What is the product and mechanism of reducing a cyclohexanone ... 14 Nov 2023 · I'm fairly sure that the first step is the reduction of the ketone by LAH, which results in a negative charge on the oxygen, that then forms a salt with the positively charged lithium. If this was just cyclohexanone, the acidic workup would simply yield a cyclohexanol.

Reduction of cyclohexanone with sodium borohydride in aqueous … A beginning organic chemistry experiment that involves the reduction of cyclohexanone with sodium borohydride in aqueous alkaline solution.

Cyclohexanone ACS reagent, = 99.0 108-94-1 - MilliporeSigma Cyclohexanone, a colorless liquid is a cyclic ketone. It is an important building block for the synthesis of a variety of organic compounds. Majority of the cyclohexanone synthesized is utilized as an intermediate in the synthesis of nylon. One of the methods reported for its synthesis is by the palladium catalyzed hydrogenation of phenol. The kinetics of the oxidation reaction of ...

Studies on the reduction of some substituted cyclohexanones Reduction of cyclohexanones. The results obtained in the reduction of the cyclo- hexanones with various reducing agents are recorded in Table 1. The sodium-n- butanol reduction afforded a single cyclohexanol from each of the cyclohexanones.

Sodium Borohydride Reduction OF Cyclohexanone - Studocu The reduction of cyclohexanone using sodium borohydride as reducing agent to produce cyclohexanol as a product. In the experiment, cyclohexanone was mixed with methanol and let it cool in the ice bath.

Reduction Of Cyclohexanone

Reducing Cyclohexanone: A Comprehensive Q&A

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