hydrogenolysis
LowTechnical
Definition
Meaning
A chemical reaction involving the cleavage of a chemical bond by hydrogen.
Specifically, a chemical reaction in which a carbon–carbon, carbon–oxygen, carbon–nitrogen, or carbon–sulfur bond in an organic compound is broken by the addition of hydrogen. It is a fundamental transformation in organic synthesis, petrochemistry, and biomass conversion, often catalysed by metals like palladium, platinum, or nickel.
Linguistics
Semantic Notes
The term is a compound of 'hydrogen' and 'lysis' (meaning 'loosening' or 'splitting'). It is often contrasted with 'hydrogenation', which adds hydrogen without breaking bonds within the molecule's core structure. Hydrogenolysis specifically implies bond scission.
Dialectal Variation
British vs American Usage
Differences
No significant lexical or orthographic differences. Spelling is consistent. Pronunciation differences follow standard UK/US patterns for the constituent parts (e.g., 'hydrogen').
Connotations
Identical technical connotations in both varieties.
Frequency
Equally rare and confined to specialised scientific literature in both regions.
Vocabulary
Collocations
Grammar
Valency Patterns
The catalyst [facilitated/promoted] the hydrogenolysis of the benzyl ether.The substrate [underwent/suffered] hydrogenolysis.Hydrogenolysis [occurs/takes place] under high pressure.Vocabulary
Synonyms
Strong
Neutral
Weak
Vocabulary
Antonyms
Phrases
Idioms & Phrases
- “None. Term is purely technical.”
Usage
Context Usage
Business
Virtually never used.
Academic
Exclusively used in chemistry, chemical engineering, and related research papers, theses, and lectures.
Everyday
Never used.
Technical
The primary context. Found in patents, process descriptions, catalyst studies, and synthetic methodology.
Examples
By Part of Speech
verb
British English
- The research team aimed to hydrogenolyse the stable ether linkage selectively.
- The compound hydrogenolysed surprisingly quickly under mild conditions.
American English
- The objective was to hydrogenolyze the benzyl protecting group.
- The model compound hydrogenolyzed at the carbon-sulfur bond.
adverb
British English
- The bond broke hydrogenolytically rather than hydrolytically.
American English
- The substrate reacted hydrogenolytically to give the deoxygenated product.
adjective
British English
- The hydrogenolytic pathway was favoured over simple hydrogenation.
- They studied the hydrogenolytic activity of various palladium catalysts.
American English
- Hydrogenolytic cleavage was confirmed by mass spectrometry.
- The catalyst's hydrogenolytic selectivity was remarkable.
Examples
By CEFR Level
- (Not applicable - word is far beyond A2 level.)
- (Not applicable - word is far beyond B1 level.)
- Scientists use hydrogenolysis to break down complex molecules.
- The process requires hydrogen and a special catalyst.
- The selective hydrogenolysis of the C-O bond in lignin model compounds is a key step in biofuel production.
- Their paper compares the efficacy of ruthenium and platinum catalysts for the hydrogenolysis of aromatic ethers.
Learning
Memory Aids
Mnemonic
Think: HYDROGEN + ana-LYSIS. Hydrogen does the 'splitting apart' (lysis) of a chemical bond.
Conceptual Metaphor
A molecular scalpel: Hydrogen acts as a tool to surgically cut specific bonds in a larger molecule.
Watch out
Common Pitfalls
Translation Traps (for Russian speakers)
- Do not confuse with 'гидролиз' (hydrolysis), which uses water, not hydrogen, to break bonds.
- The suffix '-lysis' is the same, but the agent ('hydrogeno-' vs 'hydro-') is critically different.
Common Mistakes
- Misspelling as 'hydrogenolysis' (dropping an 'o').
- Confusing it with 'hydrocracking' (a broader petroleum process that may involve hydrogenolysis).
- Using it as a synonym for general 'hydrogenation'.
Practice
Quiz
Hydrogenolysis is a reaction that primarily involves:
FAQ
Frequently Asked Questions
Hydrogenation adds hydrogen to a molecule (e.g., converting an alkene to an alkane) without breaking major skeletal bonds. Hydrogenolysis uses hydrogen to break a specific bond within the molecule (e.g., cleaving a carbon-oxygen bond).
It is crucial in petrochemical refining (e.g., hydrodesulfurization), pharmaceutical synthesis (removing protecting groups), and biorefining (converting biomass polymers like lignin into valuable chemicals).
No. Hydrolysis uses water (H2O) to break bonds. Hydrogenolysis uses molecular hydrogen (H2) to break bonds. The agents and mechanisms are different.
A classic lab example is the deprotection of a benzyl ether (C-O bond) using hydrogen gas and a palladium on carbon catalyst to yield an alcohol and toluene.