# HS code 2904.31: Perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride, perfluorooctane sulphonic acid

> HS code 2904.31 covers perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride, perfluorooctane sulphonic acid. It sits in heading 29.04 (sulphonated, nitrated or nitrosated derivatives of hydrocarbons, whether or not halogenated) in chapter 29 (organic chemicals). Other goods of heading 29.04 are classified under 2904.10 (derivatives containing only sulpho groups, their salts and ethyl esters), 2904.20 (derivatives containing only nitro or only nitroso groups), 2904.32 (perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride, ammonium perfluorooctane sulphonate), 2904.33 (perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride, lithium perfluorooctane sulphonate) or 5 others.

Source: https://staging.border.bot/hs-codes/290431
Last updated: 13 October 2026

[HS codes](https://staging.border.bot/hs-codes) / [Chapter 29](https://staging.border.bot/hs-codes/29) / [29.04](https://staging.border.bot/hs-codes/2904) / [2904.31](https://staging.border.bot/hs-codes/290431)

## Key facts

- HS code: 2904.31
- Covers: Perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride, perfluorooctane sulphonic acid
- Heading: [29.04: Sulphonated, nitrated or nitrosated derivatives of hydrocarbons, whether or not halogenated](https://staging.border.bot/hs-codes/2904)
- Chapter: [29: Organic chemicals](https://staging.border.bot/hs-codes/29)
- Edition: HS2022
- Duty rates: [Set by each country’s tariff](https://staging.border.bot/countries)

## What this code covers

HS code 2904.31 covers perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride, perfluorooctane sulphonic acid.

The legal text of the subheading is “Perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride: Perfluorooctane sulphonic acid”, read under “Perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride”, in HS2022.

## What it doesn’t cover

Other goods of heading 29.04 are classified under 2904.10 (derivatives containing only sulpho groups, their salts and ethyl esters), 2904.20 (derivatives containing only nitro or only nitroso groups), 2904.32 (perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride, ammonium perfluorooctane sulphonate), 2904.33 (perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride, lithium perfluorooctane sulphonate) or 5 others.

- [2904.10](https://staging.border.bot/hs-codes/290410) Derivatives containing only sulpho groups, their salts and ethyl esters
- [2904.20](https://staging.border.bot/hs-codes/290420) Derivatives containing only nitro or only nitroso groups
- [2904.32](https://staging.border.bot/hs-codes/290432) Perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride: Ammonium perfluorooctane sulphonate
- [2904.33](https://staging.border.bot/hs-codes/290433) Perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride: Lithium perfluorooctane sulphonate
- [2904.34](https://staging.border.bot/hs-codes/290434) Perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride: Potassium perfluorooctane sulphonate
- [2904.35](https://staging.border.bot/hs-codes/290435) Perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride: Other salts of perfluorooctane sulphonic acid
- [2904.36](https://staging.border.bot/hs-codes/290436) Perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride: Perfluorooctane sulphonyl fluoride
- [2904.91](https://staging.border.bot/hs-codes/290491) Other: Trichloronitromethane (chloropicrin)
- [2904.99](https://staging.border.bot/hs-codes/290499) Other: Other

## How it is structured

2904.31 is a six-digit subheading. Its first two digits, 29, are the chapter; the first four, 2904, are heading 29.04; the last two, 31, identify the subheading within the heading.

Countries add their own digits after these six for their national tariff lines.

- Chapter 29: Organic chemicals
- Heading 29.04: Sulphonated, nitrated or nitrosated derivatives of hydrocarbons, whether or not halogenated
- Within the heading: Perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride
- Subheading 2904.31: Perfluorooctane sulphonic acid

## In other countries

No national tariff lines under 2904.31 are live on border.bot yet. Tariffs built on the Harmonized System (HS2022) use 2904.31 at six digits and add their own digits after it.

- Previous subheading: [2904.20](https://staging.border.bot/hs-codes/290420) Derivatives containing only nitro or only nitroso groups
- Next subheading: [2904.32](https://staging.border.bot/hs-codes/290432) Perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride: Ammonium perfluorooctane sulphonate

## Frequently asked questions

### What does HS code 2904.31 cover?

HS code 2904.31 covers perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride, perfluorooctane sulphonic acid.

### Which heading and chapter is HS code 2904.31 in?

HS code 2904.31 is in heading 29.04 (sulphonated, nitrated or nitrosated derivatives of hydrocarbons, whether or not halogenated) in chapter 29 (organic chemicals).

### Where are goods of heading 29.04 classified when 2904.31 doesn’t fit?

Other goods of heading 29.04 are classified under 2904.10 (derivatives containing only sulpho groups, their salts and ethyl esters), 2904.20 (derivatives containing only nitro or only nitroso groups), 2904.32 (perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride, ammonium perfluorooctane sulphonate), 2904.33 (perfluorooctane sulphonic acid, its salts and perfluorooctane sulphonyl fluoride, lithium perfluorooctane sulphonate) or 5 others.

## Sources and updates

The Harmonized System legal text comes from border.bot release 1 (edition HS 2022), imported from a file, and has been live since 13 October 2026.

This page was last updated on 13 October 2026.

Guidance from published tariff data, not a binding ruling. For a decision customs must follow, apply to the destination’s customs authority for a binding tariff ruling.

Machine-readable: https://staging.border.bot/hs-codes/290431.json