Main-Product

A sulfide (also called thioether) is an organosulfur compound with the general structure R-S-R', where R and R' are organic groups connected by a sulfur atom.

These compounds have distinct structural characteristics:

Key Features

• Angular C-S-C bond with angles approaching 90°
• C-S bond lengths of approximately 180 picometers
• Similar to ethers but with sulfur replacing oxygen
• Less volatile and less hydrophilic than corresponding ethers
• Typically possess strong, characteristic odor

Chemical Properties

The sulfur atom in these compounds:

• Acts as a nucleophile due to its 3P orbital electrons
• Forms stronger nucleophiles than oxygen analogs
• Can undergo electrophilic substitutions
• Readily forms coordination complexes with metals

Liquid sulfides

Commonly encountered liquid sulfides in fossil hydrocarbons by increasing molecular weight:

• Dimethyl Sulfide (CH₃-S-CH₃): 38°C boiling point
• Methyl ethyl sulfide (CH₃-S-C₂H₅): 66°C boiling point
• Thiophene - a cyclic sulfide (C₄H₄S): 84°C boiling point
• Diethyl Sulfide (C₂H₅-S-C₂H₅): 92°C boiling point
• Methyl propyl sulfide (CH₃-S-C₃H₇): 96°C boiling point
• Ethyl propyl sulfide (C₂H₅-S-C₃H₇): 117°C boiling point
• Diisopropyl sulfide (C₃H₇-S-C₃H₇): 120°C boiling point
• Dipropyl sulfide (C₃H₇-S-C₃H₇): 142°C boiling point

Occurence

Dimethyl sulfide is the most abundant sulfide in fossil sources; diethyl sulfide is also commonly present; Higher molecular weight sulfides occur in decreasing amounts as molecular weight increases.

These compounds are found in:

• Crude oil and its derivatives
• Natural gas condensates
• Marine-sourced hydrocarbons

References

1. Perplexity A.I. search, 1^st Jan 2024, Prompt 'what are the most common sulfides found in fossil hydrocarbons?' and follow-up prompts.