Pentacosane

Pentacosane	Last updated: 27/08/2025
(Also known as: n-pentacosane)

Hazard alerts

The following alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement. These hazard alerts do not take account of usage patterns or exposure, thus do not represent risk.

Environmental fate	Ecotoxicity	Human health
	Ecotoxicity Low alert: Bees acute contact ecotoxicity: Low; Bees acute unknown ecotoxicity: Low Warning: Significant data are missing

GENERAL INFORMATION

Description

An aliphatic saturated hydrocarbon found in most insects that is used as an attractant for aphid parasitoids

Example pests controlled

Aphids

Example applications

Vegetables

Efficacy & activity

Appearance and life cycle

Taxonomic classification

GB regulatory status

GB COPR regulatory status

Not approved

Date COPR inclusion expires

Not applicable

GB LERAP status

No UK approval for use as a plant protection agent

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Not approved

Dossier rapporteur/co-rapporteur

Not applicable

Date EC 1107/2009 inclusion expires

Not applicable

EU Candidate for substitution (CfS)

Not applicable

Listed in EU database

Approved for use (✓) under EC 1107/2009 in the following EU Member States

ATAustria	BEBelgium	BGBulgaria	CYCyprus	CZCzech Republic	DEGermany	DKDenmark	EEEstonia	ELGreece

ESSpain	FIFinland	FRFrance	HRCroatia	HUHungary	IEIreland	ITItaly	LTLithuania	LULuxembourg

LVLatvia	MTMalta	NLNetherlands	PLPoland	PTPortugal	RORomania	SESweden	SISlovenia	SKSlovakia

Approved for use (✓) under EC 1107/2009 by Mutual Recognition of Authorisation and/or national regulations in the following EEA countries

ISIceland	NONorway

Additional information

Known to be also used in the following countries

Chemical structure

Isomerism

Pentacosane is isomeric in the broader chemical sense. While n-pentacosane refers specifically to the straight-chain version of the molecule, its formula allows for many structural isomers due to the possibility of branching in the carbon chain.

Chemical formula

C₂₅H₅₂

Canonical SMILES

CCCCCCCCCCCCCCCCCCCCCCCCC

Isomeric SMILES

International Chemical Identifier key (InChIKey)

YKNWIILGEFFOPE-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C25H52/c1-3-5-7-9-11-13-15-17-19-21-23-25-24-22-20-18-16-14-12-10-8-6-4-2/h3-25H2,1-2H3

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
pentacosane	-

General status

Biopesticide type

Semiochemical; Insecticide

Substance groups

Animal-derived substance; Plant-derived substance; Pheromone

Minimum active substance purity

>97%

Known relevant impurities

Substance origin

Natural

Mode of action

Contact sex pheromone released by the female of the species and used in traps. Short lived activity.

Substance source

Occurs in beeswax but also found in other natural waxes and some plants including Euphorbia piscatoria and Vanilla madagascariensis

Uses

Crop protection

Target pests

Aphids

Target host

Vegetables

Farming system suitability

CAS RN

629-99-2

EC number

211-123-6

CIPAC number

None

US EPA chemical code

PubChem CID

12406

Molecular mass

352.69

PIN (Preferred Identification Name)

IUPAC name

n-pentacosane

CAS name

n-pentacosane

Forever chemical

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

Not applicable

Herbicide Resistance Class (WSSA MoA class)

Not applicable

Insecticide Resistance Class (IRAC MoA class)

UNM

Fungicide Resistance Class (FRAC MOA class)

Not applicable

Examples of recorded resistance

Physical state

Colourless solid

Commercial

Property

Value

Availability status

Current

Introduction & key dates

early 20th century, discovered

Example manufacturers & suppliers of products using this active now or historically

Fine Chemicals
MP Biomedicals

Example products using this active

n-Pentacosane

Formulation and application details

Pentacosane is most commonly available in solid form

Commercial production

Pentacosane is commercially produced through either fractional distillation of petroleum waxes or extraction from natural sources such as plant essential oils. In the petroleum-based route, high-molecular-weight paraffins are isolated from crude oil refining residues and then subjected to vacuum distillation to separate pentacosane based on its boiling point. For natural extraction, plants like Curcuma longa or Malus domestica are processed using solvent extraction, typically with acetone or hexane, to isolate waxy components, followed by chromatographic purification to obtain high-purity pentacosane.

Impact on climate of production and use

While exact CO₂e values are not published for specific pheromones, some general information is available. The PHERA reported that biotechnological production (e.g. yeast fermentation) of pheromones can reduce GHG emissions by up to 90% compared to traditional chemical synthesis and GHG emissions are typically in the 5 to 10 kg CO₂e per kg of pheromone produced. Other sources suggest that small scale pheromone synthesis typically has emissions in the range 1 – 3 kg CO₂e per kg of pheromone produced.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

Solubility - In water at 20 °C (mg l⁻¹)

0.005

Low

Solubility - In organic solvents at 20 °C (mg l⁻¹)

Melting point (°C)

Boiling point (°C)

401

Degradation point (°C)

Flashpoint (°C)

>230

Octanol-water partition coefficient at pH 7, 20 °C

4.17 X 10¹²

Calculated

Log P

12.62

High

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

0.80

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

0.266

Low volatility. If applied directly to plants, drift is a concern & mitigation is advisable

Henry's law constant at 25 °C (Pa m³ mol⁻¹)

3.77 X 10⁰⁷

Volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

Maximum UV-vis absorption L mol⁻¹ cm⁻¹

Surface tension (mN m⁻¹)

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

Dissipation rate RL₅₀ (days) on plant matrix

Value

Note

Dissipation rate RL₅₀ (days) on and in plant matrix

Value

Note

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Note

Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7

Value

Note

Water-sediment DT₅₀ (days)

Water phase only DT₅₀ (days)

Sediment phase only DT₅₀ (days)

Air degradation

As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below.

Decay in stored produce DT₅₀

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d (mL g⁻¹)

K_oc (mL g⁻¹)

Notes and range

Freundlich

K_f (mL g⁻¹)

K_foc (mL g⁻¹)

¹/_n

Notes and range

pH sensitivity

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

Mammals - Short term dietary NOEL

(mg kg⁻¹)

(ppm diet)

Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)

Birds - Acute LD₅₀ (mg kg⁻¹)

Birds - Short term dietary (LC₅₀/LD₅₀)

Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)

Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹ dw soil)

Earthworms - Chronic NOEC, reproduction (mg kg⁻¹ dw soil)

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Vegetative vigour ER₅₀ (g ha⁻¹)

Seedling emergence ER₅₀ (g ha⁻¹)

Honeybees (Apis spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 100

Low

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 100

Expert judgement

Low

Chronic

Notes

Bumblebees (Bombus spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Mason bees (Osmia spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Other bee species (1)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Other bee species (2)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Beneficial insects (Ladybirds)

Beneficial insects (Lacewings)

Beneficial insects (Parasitic wasps)

Beneficial insects (Predatory mites)

Beneficial insects (Ground beetles)

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)

Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)

Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)

Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)

Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)

Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)

Aquatic Plants (free-floating, fonds growth, fresh) - 7 day (mg l⁻¹)

Aquatic plants (rooted, growth rate, fresh) - 14 day (mg l⁻¹)

Algae - Acute (growth rate, fresh; mg l⁻¹)

Algae - Chronic (growth rate, fresh; mg l⁻¹)

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves

HUMAN HEALTH AND PROTECTION

General

Property

Value

Source; quality score; and other information

Interpretation

Threshold of Toxicological Concern (Cramer Class)

Low (class I)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)

ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)

AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)

AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Occupational

Mammalian dose elimination route and rate

Health issues

Specific human health issues (hazard-based)

Carcinogen

Genotoxic

Endocrine disruptor

No data found

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

Digestive tract irritant
Prevent skin exposure

Handling issues

Property

Value and interpretation

General

Incompatible with strong oxiding agents

CLP classification 2013

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

pentacosane

French

German

Danish

Italian

Spanish

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	27/08/2025
Contact:	aeru@herts.ac.uk
Please cite as:	Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242