Hydrogenation vs. Hydrogenolysis — What's the Difference?
By Tayyaba Rehman & Fiza Rafique — Updated on May 20, 2024
Hydrogenation adds hydrogen to molecules, typically converting unsaturated compounds to saturated ones, while hydrogenolysis breaks chemical bonds using hydrogen, often cleaving C-C or C-X bonds.
Difference Between Hydrogenation and Hydrogenolysis
Table of Contents
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Key Differences
Hydrogenation is a chemical process that involves the addition of hydrogen (H₂) to an organic compound, typically in the presence of a catalyst like palladium, nickel, or platinum. Hydrogenolysis, on the other hand, involves the breaking (lysis) of chemical bonds using hydrogen. It often targets carbon-carbon (C-C) or carbon-heteroatom (C-X) bonds, such as the breaking down of larger organic molecules into smaller ones.
Hydrogenation typically aims to change the degree of saturation of a molecule without significantly altering its carbon skeleton. In contrast, hydrogenolysis alters the molecule's structure more fundamentally by breaking specific bonds, leading to smaller or different molecules.
Both processes are catalytic and require specific conditions of temperature and pressure. Hydrogenation is primarily used in food and chemical industries to modify fats and oils, whereas hydrogenolysis is often applied in the degradation of biomass and refining of petroleum products.
Comparison Chart
Definition
Addition of hydrogen to compounds
Breaking of bonds using hydrogen
Purpose
Saturation of unsaturated compounds
Cleavage of C-C or C-X bonds
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Applications
Food industry (e.g., margarine production)
Petrochemical refining, biomass conversion
Catalyst
Palladium, nickel, platinum
Typically metals like nickel, palladium
Process Outcome
Converts double/triple bonds to single bonds
Produces smaller molecules by breaking bonds
Example Reaction
Unsaturated fat to saturated fat
Breaking down cellulose to glucose
Compare with Definitions
Hydrogenation
Process of converting double bonds to single bonds.
The hydrogenation of alkenes produces alkanes.
Hydrogenolysis
Process that splits molecules into smaller parts.
Hydrogenolysis is used to break down lignin in biomass.
Hydrogenation
Requires a catalyst like nickel or platinum.
Nickel catalyzed hydrogenation is common in industrial processes.
Hydrogenolysis
Breaking of chemical bonds using hydrogen.
Hydrogenolysis cleaves C-C bonds in hydrocarbons.
Hydrogenation
A method to saturate organic molecules.
Hydrogenation of fatty acids increases their melting point.
Hydrogenolysis
Requires a catalyst, often metal-based.
Palladium is a common catalyst for hydrogenolysis reactions.
Hydrogenation
Often used in the food industry for modifying fats.
Hydrogenation is used to make trans fats in processed foods.
Hydrogenolysis
Typically involves cleaving C-C or C-X bonds.
Hydrogenolysis of esters produces alcohols and acids.
Hydrogenation
Chemical addition of hydrogen to unsaturated compounds.
Hydrogenation turns vegetable oil into margarine.
Hydrogenolysis
Used in refining and chemical processing industries.
Petroleum refining often involves hydrogenolysis of complex molecules.
Hydrogenation
Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic compounds.
Hydrogenolysis
Hydrogenolysis is a chemical reaction whereby a carbon–carbon or carbon–heteroatom single bond is cleaved or undergoes lysis (breakdown) by hydrogen. The heteroatom may vary, but it usually is oxygen, nitrogen, or sulfur.
Hydrogenation
(chemistry) The chemical reaction of hydrogen with another substance, especially with an unsaturated organic compound, and usually under the influence of temperature, pressure and catalysts.
Hydrogenolysis
The breaking of a chemical bond in an organic molecule with the simultaneous addition of a hydrogen atom to each of the resulting molecular fragments.
Hydrogenation
The act of combining with hydrogen, or the state of being so combined.
Hydrogenolysis
(chemistry) the cleavage of a molecule, especially that of a carbon-carbon bond, with the addition of hydrogen atoms to the fragments
Hydrogenation
A chemical process that adds hydrogen atoms to an unsaturated oil;
Food producers use hydrogenation to keep fat from becoming rancid
Common Curiosities
What industries use hydrogenolysis?
Hydrogenolysis is used in petrochemical refining and biomass conversion.
What is hydrogenolysis?
Hydrogenolysis is the breaking of chemical bonds using hydrogen, resulting in smaller molecules.
What type of bonds does hydrogenation affect?
Hydrogenation primarily affects carbon-carbon double or triple bonds.
What industries use hydrogenation?
Hydrogenation is widely used in the food industry to convert oils into fats like margarine.
What is hydrogenation?
Hydrogenation is the addition of hydrogen to unsaturated compounds to make them saturated.
What catalysts are used in hydrogenation?
Common catalysts for hydrogenation include nickel, palladium, and platinum.
Does hydrogenation change the molecular structure significantly?
Hydrogenation does not significantly alter the carbon skeleton of the molecule.
Does hydrogenolysis change the molecular structure significantly?
Yes, hydrogenolysis alters the molecular structure by breaking bonds and forming new ones.
What catalysts are used in hydrogenolysis?
Hydrogenolysis typically uses metal catalysts such as nickel or palladium.
Is hydrogenolysis reversible?
Hydrogenolysis is typically not reversible, as it breaks chemical bonds.
What type of bonds does hydrogenolysis affect?
Hydrogenolysis can break carbon-carbon (C-C) or carbon-heteroatom (C-X) bonds.
Is hydrogenation reversible?
Hydrogenation is generally not reversible under normal conditions.
What is an example of hydrogenolysis?
Breaking down cellulose into glucose using hydrogenolysis.
Can both processes be used together?
Yes, in some industrial processes, hydrogenation and hydrogenolysis can be used sequentially to achieve desired chemical transformations.
What is an example of hydrogenation?
Converting vegetable oil into solid margarine through hydrogenation.
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Written by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
Co-written by
Fiza RafiqueFiza Rafique is a skilled content writer at AskDifference.com, where she meticulously refines and enhances written pieces. Drawing from her vast editorial expertise, Fiza ensures clarity, accuracy, and precision in every article. Passionate about language, she continually seeks to elevate the quality of content for readers worldwide.
