Main-Product

Naphtha is a broad term applied to several distinct mixtures of liquid hydrocarbons characterized by high volatility, low boiling points, and significant flammability. These mixtures are obtained primarily through the distillation of petroleum or coal tar, and occasionally through the distillation of wood, giving rise to the designations petroleum naphtha, coal-tar naphtha, and wood naphtha respectively.

Product Types

Petroleum naphtha — by far the most commercially significant category — is itself subdivided based on boiling range and hydrocarbon composition:

• Straight-run naphtha (SRN) / Full-range naphtha (FRN): Produced directly from atmospheric distillation of crude oil without further conversion processing; encompasses the full C₅–C₁₀ boiling cut and is often traded as a single stream before being split at the refinery or petrochemical complex into light and heavy fractions. Composition is highly dependent on crude origin.
• Light naphtha (LN): Boiling range approximately 30–90°C; rich in C₅–C₆ paraffins and isomers; primarily used as a blending component for gasoline and as a petrochemical feedstock in steam crackers
• Heavy naphtha (HN): Boiling range approximately 90–200°C; richer in C₇–C₁₀ naphthenes and aromatics; the preferred feedstock for catalytic reforming to produce high-octane gasoline components and BTX aromatics (benzene, toluene, xylene)
• Catalytic naphtha: Derived from fluid catalytic cracking (FCC) units processing vacuum gas oil or residues; typically high in olefins and aromatics, with elevated sulfur levels, requiring hydrotreating before use as a gasoline blending component or further processing
• Hydrocracked naphtha: Produced in resid hydrocracking units operating under high hydrogen partial pressure; characteristically low in sulfur, high in paraffins and isoparaffins, and essentially olefin-free — making it a premium feedstock for steam crackers and catalytic reformers
• Coker naphtha: Produced in delayed or fluid coking units processing heavy residues; high in olefins and sulfur, requiring significant hydrotreating

Coal-tar naphtha, a by-product of coal carbonization, is notably richer in aromatic compounds (benzene, toluene, xylene, and naphthalene precursors) and heavier unsaturated species. Wood naphtha, historically produced by the destructive distillation of wood, is primarily methanol-based and has largely been supplanted by synthetic alternatives.

Compositional Data

Table 1 shows the composition of a full range naphtha obtained directly from the Atmospheric Distillation Unit: 

Table 1 — Example of a full boiling range naphtha composition

Typical molecular compounds in the five different hydrocarbon classes present in naphtha are shown in Figure 1: 

Figure 1 — Key hydrocarbon classes and molecular compounds in petroleum naphtha

Figure 2 shows typical PIONA compositions for various types of naphtha:

Figure 2 — Naphtha PIONA composition by type

Key Characterization Parameters

The different naphthas are distinguished by several analytical measures:

• Density (g/ml or specific gravity), which correlates broadly with aromatic content and molecular weight
• Boiling range / distillation curve (ASTM D86), defining the IBP (initial boiling point) to FBP (final boiling point) cut
• PONA, PIONA, or PIANO analysis, measuring hydrocarbon class composition, typically in volume percent or weight percent: Paraffins, Isoparaffins (in PIONA/PIANO), Olefins, Naphthenes (cycloparaffins), and Aromatics
• Research Octane Number (RON) and Motor Octane Number (MON), relevant for gasoline blending streams
• Sulfur content (ppm or wt%), critical for downstream processing and regulatory compliance
• Reid Vapor Pressure (RVP), reflecting volatility and handling/safety requirements

Principal Applications

Naphtha serves as a crucial intermediate across multiple industries:

• Gasoline production: Heavy naphtha is the primary feedstock for catalytic reforming, upgrading low-octane naphthenes and paraffins into high-octane aromatics and hydrogen
• Petrochemicals — olefins: Light and full-range naphtha are major feedstocks for steam crackers, producing ethylene, propylene, butadiene, and pyrolysis gasoline
• Petrochemicals — aromatics: Catalytic reformate derived from heavy naphtha feeds BTX extraction units supplying benzene, toluene, and xylenes to the chemical industry
• Hydrogen production: Naphtha can be steam-reformed to produce hydrogen or syngas supplied to ammonia or methanol plants
• Solvents and cleaning agents: Light petroleum naphthas are widely used as industrial solvents, degreasers, and diluents in paints, adhesives, and dry-cleaning formulations

References

1. New World Encyclopedia — Naphtha (June 2, 2025)
2. Wikipedia — Petroleum Naphtha (edited on May 13, 2026)
3. Patsnap Eureka — Straight-Run vs. Cracked Naphtha: Key Differences in Composition (June 19, 2025)
4. ECHA Chemical Registry — Naphtha (petroleum), light straight-run (accessed Jun 3, 2026)
5. Chandra Asri — What Is Naphtha? Properties, Functions, & How to Process It (Jun 8, 2025)
6. Energies (MDPI) / Loyola University — Naphtha Characterization (PIONA, Density, Distillation Curve and Sulfur Content) (Jan 1, 2023)
7. Mihail Editoiu (YouTube) — Naphtha Splitter - Letter of Award & Basis of Design (Sep 17, 2021)