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Indene

HCID 7219
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Basic informationOverviewNames & identifiersPropertiesSafety & regulationChemistry & industryRelated reactionsCompound notes
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Basic information

CAS
71551-80-9
Standard SMILES
C1=Cc2ccccc2C1
InChIKey
YBYIRNPNPLQARY-UHFFFAOYSA-N
Molecular formula
C9H8
Average molar mass
116.16 g/mol
Monoisotopic mass
116.06260026

Overview

Indene appears as a colorless liquid derived from coal tar. Fp: -2 °C; bp:182 °C. Density 0.997 g cm-3. Insoluble in water but soluble in organic solvents.

Names & identifiers

Preferred name
Indene
IUPAC
1H-indene
English name
Indene
Molecular formula
C9H8
Molecular weight
116.16

Names & synonyms

INDENE1H-Indene95-13-6IndonaphtheneIndenDTXSID8042052NSC 927067H8Y6LB8ANSC-9270DTXCID6022052CHEBI:41921RefChem:790898
Show more names
Technicalindenendene1-indeneIndene >Indene,90+%Indene techIndene Odor
CHEBI:37910202-393-6Indenyl radicalMFCD00003777indene, (1H-indene)INDENE, REAGWLN: L56 BHJCHEMBL192812

Database identifiers

CAS
71551-80-9、9003-64-9、95-13-6
PubChem CID
7219
DTXSID
DTXSID8042052
ChEMBL
CHEMBL192812、CHEMBL506735
ChEBI
CHEBI:41921
UNII
67H8Y6LB8A
EC Number
202-393-6
Nikkaji
J4.708B

Properties

Computed structural propertiesFilling in

XLogP
2.9
Topological polar surface area
0 Ų
Hydrogen bond donors
0
Hydrogen bond acceptors
0
Rotatable bonds
0
Heavy atoms
9
Formal charge
0
Complexity
124

Experimental & physicochemical properties

Chemical Classes · 2 items

Other Classes -> Aromatic Hydrocarbons

Flammable agents - 2nd degree

SpringerMaterials Properties13C nuclear magnetic resonance spectrum
FragrancesFragrance Ingredient (1H-Indene) -> IFRA transparency List
LogP · 2 items

Log Kow = 2.92

2.92

Density · 5 items

0.997 (NIOSH, 2024) - Less dense than water; will float

0.9968 @ 20 °C/4 °C

0.997

0.996 @25 °C

0.997

Color/Form · 3 items

LIQUID

Colorless liquid

Colorless liquid [Note: A solid below 29 degrees F].

Solubility · 5 items

Insoluble (NIOSH, 2024)

INSOL IN WATER, MISCIBLE WITH MOST ORGANIC SOLVENTS

SOL IN ALL PROPORTIONS IN ALC, ETHER, N BENZENE, PYRIMIDENE, CARBON DISULFIDE

Soluble in ethanol; it is miscible with diethyl ether, naphtha, pyridine, carbon tetrachloride, chloroform, and carbon disulfide

Safety & regulation

Safety information is for reference only and does not replace the supplier’s Safety Data Sheet (SDS), applicable regulations, or professional assessment.

GHS classification

GHS Classification · 6 items

This chemical does not meet GHS hazard criteria for 0.5% (2 of 400) of reports.

Danger

H226 (99.2%): Flammable liquid and vapor [Warning Flammable liquids]

P210, P233, P240, P241, P242, P243, P264, P264+P265, P273, P280, P301+P316, P302+P352, P303+P361+P353, P305+P351+P338, P321, P331, P332+P317, P337+P317, P362+P364, P370+P378, P391, P403+P235, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 400 reports by companies from 16 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Danger

Hazard information

Regulatory Information · 5 items

Chemical: 1H-Indene

1H-Indene is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of 1H-Indene are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)

REACH registered substance: Indene (EC: 202-393-6)

Indene: Does not have an individual approval but may be used under an appropriate group standard

The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.)

DOT LabelCombustible Liquid
Fire HazardsExcerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]:
Fire PotentialDEFLAGRATES ON HEATING. /INDENE PICRATE/
Health HazardsExcerpt from NIOSH Pocket Guide for Indene:

Chemistry & industry

Pharmacology

Metabolism/Metabolites · 3 items

YIELDS CIS-1,2-DIHYDROXYINDANE & TRANS-1,2-DIHYDROXYINDANE IN RABBITS. /FROM TABLE/

RAT-LIVER MICROSOMES SUPPLEMENTED WITH NADPH CONVERTED INDENE INTO TRANS-INDANE-1,2-DIOL ...

THE OXIDATION OF INDENE TO TRANS-1,2-DIHYDROXYINDANE IN LIVER PREPN IN VITRO WAS DEMONSTRATED. THE REACTION WAS MEDIATED BY LIVER MICROSOMES OF RATS & RABBITS IN THE PRESENCE OF NADPH-GENERATING SYSTEMS.

Uses & manufacturing

Uses · 4 items

Used to prepare coumarone-indene resins; [ACGIH]

Plastic Composites Manufacturing [Category: Industry]

Used as a comonomer in coumarone and petroleum-derived aromatic hydrocarbon resins. Technical pure indene is used for the production of indan and its derivatives. Esters of indene-1-carboxylic acid, which are effective as acaricides, can be synthesized from indene for use in, eg, collars

It is composed of a benzene ring fused with a cyclopentene ring.

U.S. Production2023: 500,000 - <1,000,000 lb
Industry UsesMonomers
Methods of Manufacturing · 2 items

... FROM ACETYLENE OVER ACTIVATED CHARCOAL @ 625 °C ... MFR FROM TETRAHYDRONAPHTHALENE BY PASSING OVER SIO2-AL2O3 CATALYST @ 670 °C

Pyrolysis residual oils from olefin production contain varying amounts of indene, which can be separated by extractive distillation with N-methyl-2- pyrrolidone or by crystallization. Indene is recovered industrially from dephenolated and debased tar light oil by rectifying distillation followed by crystallization. When the phenol extraction is omitted a highly concentrated indene fraction can also be obtained by azeotropic distillation of an indene- phenol fraction with water, whereby the phenol is separated as a bottom product.

Use ClassificationFragrance Ingredients

Related reactions

215 records
New reaction record
HRID 1306 reaction equation
HRID 1306As reactantuspto-grants-1998_03
HRID 22443 reaction equation
HRID 22443As reactantuspto-grants-1995_06
HRID 22444 reaction equation
HRID 22444As reactantuspto-grants-1995_06
HRID 36480 reaction equation
HRID 36480As productuspto-grants-1995_05
HRID 39114 reaction equation
HRID 39114As reactantuspto-grants-2013_09
HRID 47413 reaction equation
HRID 47413As reactantuspto-grants-2004_03
HRID 52676 reaction equation
HRID 52676As reactantuspto-grants-1997_04
HRID 52819 reaction equation
HRID 52819As productuspto-grants-1997_04
Page 1 of 27

Compound notes

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Insoluble

Flash Point · 5 items

173 °F (NIOSH, 2024)

173 °F

173 °F

173 °F

173 °F

Boiling Point · 5 items

359 °F at 760 mmHg (NIOSH, 2024)

181.6 °C 760 MM HG

359 °F

182 °C @760 [mm Hg]

359 °F

Melting Point · 5 items

29 °F (NIOSH, 2024)

-1.8 °C

29 °F

-1.5 °C

29 °F

Odor ThresholdOdor Threshold Low: 0.0042 [ppm]
Vapor Pressure · 3 items

1.1 [mmHg]

1.1 mm Hg at 25 °C

0.75 [mm Hg] @12 °C

Physicochemical properties

Melting point
-5 · -5--3 °C (lit.)
Boiling point
181 · 181-182 °C (lit.)
Density
0.996 g/mL · 0.996 g/mL at 25 °C (lit.)
vapor pressure
1.7 hPa · 1.7 hPa (20 °C)
refractive index
20 · n20/D 1.595(lit.)
Flash point
138 °F · 138 °F
storage temp.
2 · 2-8°C
solubility
organic solvents: miscible
pka
20 · 20(at 25℃)
form
Crystalline Powder
color
White to pale yellow
Odor Threshold
0.0038 ppm · 0.0038ppm
Water Solubility
INSOLUBLE
Specific Heat Capacity
1.61 J/ · Cp(liquid): 1.61 J/(g·K), at 25℃
Sensitive
Light Sensitive
Merck
14 · 14,4939
BRN
635873 · 635873
Henry's Law Constant
6.2 · 6.2×10-3 mol/(m3Pa) at 25℃, HSDB (2015)
Exposure limits
50 mg/m3 · PC-TWA:50 mg/m3
Stability
80 · Stable, but air and light sensitive; may polymerize upon exposure to light. Typically contains aroung 80 - 100 ppm of p-tert-butylcatechol as inhibitor. Refrigerate. Flammable. Incompatible with strong oxidizing agents.
Cosmetics Ingredients Functions
PERFUMING
InChI
1S/C9H8/c1-2-5-9-7-3-6-8(9)4-1/h1-6H,7H2
InChIKey
YBYIRNPNPLQARY-UHFFFAOYSA-N
SMILES
C1C=Cc2ccccc12
LogP
3.02 at · 3.02 at 25℃ and pH6.4
FDA 21 CFR
175.105 · 175.105
Indirect Additives used in Food Contact Substances
INDENE
CAS DataBase Reference
95 · 95-13-6(CAS DataBase Reference)
EWG's Food Scores
1 · 1
FDA UNII
67 H8Y6LB8A · 67H8Y6LB8A
NIST Chemistry Reference
Indene(95-13-6)
EPA Substance Registry System
Indene (95-13-6)
UNSPSC Code
12352100 · 12352100
NACRES
22 · NA.22
Symbol(GHS)
2 · GHS02,GHS08
Signal word
Danger
Hazard statements
226 · H226-H304
Precautionary statements
210 · P210-P233-P240-P241-P301+P310-P331
PPE
Eyeshields, Faceshields, Gloves, type ABEK (EN14387) respirator filter
Hazard Codes
Xn
Risk Statements
10 · 10-65-36/37/38-20
Safety Statements
23 · 23-24/25-62-37/39-26
OEB
A
OEL
10 ppm · TWA: 10 ppm (45 mg/m3)
RIDADR
3295 · UN 3295 3/PG 3
WGK Germany
1 · 1
RTECS
8225000 · NK8225000
F
8 · 8
TSCA
TSCA listed
HS Code
2902 · 2902 90 00
HazardClass
3 · 3
PackingGroup
III
Storage Class
3 · 3 - Flammable liquids
Hazard Classifications
1 Flam · Asp. Tox. 1Flam. Liq. 3
Hazardous Substances Data
95 · 95-13-6(Hazardous Substances Data)
REACH Registrations
Active
Limited Quantities
5 L · 5.0 L (1.3 gallons) (liquid)
Excepted Quantities
Max Inner Pack (30g or 30ml) and Max Outer Pack (1Kg or 1L)
Hazards Summary
Animals exposed to 800-900 ppm for six 7-hour periods show evidence of liver and kidney injury. [ACGIH]
Reactive GroupHydrocarbons, Aromatic
Reactivity AlertsPolymerizable
Reactivity Profile · 1 item

INDENE is combustible (flash point between 140 °F and 200 °F). Polymerizes and oxidizes on standing in the air. This reaction is accelerated by heating, acids, and catalysts, including peroxides. Has exploded during nitration with a mixture of H2SO4 and HNO3.

Flammable LimitsClass IIIA Combustible Liquid: Fl.P. at or above 140 °F and below 200 °F.
Air and Water ReactionsPeroxide formation with air with initiation of polymerization
NIOSH RecommendationsRecommended Exposure Limit: 10 Hr Time-Weighted Avg: 10 ppm (45 mg/cu m).

Safety & protection

Fire FightingExcerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]:
First Aid · 2 items

Excerpt from NIOSH Pocket Guide for Indene:

(General first aid procedures)

Nonfire Spill ResponseExcerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]:
Disposal Methods · 1 item

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

Preventive Measures · 2 items

The worker should wash daily at the end of each work shift.

Work clothing that becomes wet or significantly contaminated should be removed and replaced.

Isolation and EvacuationExcerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]:
Respirator RecommendationsImportant additional information about respirator selection
Threshold Limit Values (TLV) · 4 items

5.0 [ppm]

8 hr Time Weighted Avg (TWA): 5 ppm.

Excursion Limit Recommendation: Excursions in worker exposure levels may exceed 3 times the TLV-TWA for no more than a total of 30 minutes during a work day, and under no circumstances should they exceed 5 times the TLV-TWA, provided that the TLV-TWA is not exceeded.

5 ppm [2007]

Permissible Exposure Limit (PEL) · 2 items

10 ppm (45 mg/m³) OSHA Construction and Maritime industries only.

none See Appendix G

Protective Action Criteria (PAC) · 3 items

70 [mg/m3]

100 [mg/m3]

620 [mg/m3]

Recommended Exposure Limit (REL) · 2 items

10 ppm (45 mg/m³)

TWA 10 ppm (45 mg/m3)

Personal Protective Equipment (PPE) · 3 items

Excerpt from NIOSH Pocket Guide for Indene:

Wear appropriate personal protective clothing to prevent skin contact.

Wear appropriate eye protection to prevent eye contact.

Toxicology

Toxicological InformationRanking: 303 (total points: 714.72)
Body Burden · 1 item

Indene was detected in respiratory gas from 7 of 8 male volunteers (3 smokers) at a concn range of 0.14-83 ug/hr-expired air; according to this study, indene may result from or be related to normal human metabolism(1). Indene was found at an average concn of 0.138 ng/L in 59 of 387 expired air samples obtained from 54 nonsmoking-volunteers(2).

Target OrgansEyes, skin, respiratory system, liver, kidneys, spleen
Environmental Fate · 3 items

TERRESTRIAL FATE: The estimated Koc value of 540(1-2,SRC) suggests that indene will have low mobility in soil(3). If spilled on soil surfaces, some indene may photolyze(4,SRC) or volatilize into the air (estimated Henry's Law constant of 1.59X10-3 atm-cu m/mol at 25 °C(5)). However, adsorption may limit these processes(SRC). Limited data suggest indene is biodegradable in soil(6-7).

AQUATIC FATE: Based on the estimated Koc value of 540(1-2,SRC), indene may adsorb to sediment; indene was found in a river sediment(3). Oxidation via reaction with sunlight produced alkyl peroxy radicals is very slow (estimated half-life of 1,100 days(4)). Limited data suggest indene is biodegradable. Indene may be susceptible to some direct photolysis in sunlight(5); however, this is not expected to be an important removal process(SRC). Indene is not expected to hydrolyze in the aquatic environments(SRC). Volatilization from water is fast with estimated half-lives of 3.7 hrs and 4.4 days from a model river and model lake, respectively(1,SRC).

ATMOSPHERIC FATE: Based upon a measured vapor pressure of 1.1 mm Hg at 25 °C(1), indene is expected to exist almost entirely in the vapor phase in the ambient atmosphere(2,SRC). Vapor-phase indene will degrade rapidly in the ambient atmosphere by reaction with photochemically produced hydroxyl radicals with an estimated half-life of about 6.2 hours(3,SRC).

Food Survey ValuesIndene was qualitatively identified as a volatile component of roasted filberts(1).
Adverse EffectsOccupational hepatotoxin - Secondary hepatotoxins: the potential for toxic effect in the occupational setting is based on cases of poisoning by human ingestion or animal experimentation.
Exposure Routesinhalation, ingestion, skin and/or eye contact
Signs and SymptomsIn Animals: irritation eyes, skin, mucous membrane; dermatitis, skin sensitization; chemical pneumonitis (aspiration liquid); liver, kidney, spleen injury
Effluent Concentrations · 2 items

Indene was qualitatively identified in effluents from a POTW facility in Sauget, Illinois(1). On October 24, 1974, indene was qualitatively found in advanced waste treatment concentrates from Lake Tahoe, CA(2). During August and September of 1979, indene was found at a concn range of 0.08-0.4 ug/cu-m in the Allegheny Mountain Tunnel in Pennsylvania(3). Indene was identified at a concn range of 10.3-137.6 ng/L in paper-mill effluents being discharged into the Rainy River(4). Indene was identified in a plume of contaminated water moving through sand away from creosote waste disposal lagoons(5). Indene was found at a concn of 1.28 in an air sample taken near an oil fire(6).

Indene was found in a groundwater sample prior to coal gasification (0.03 ppm), process water during gasification (272 and 72 ppm), and aqueous condensate from low-BTU coal gasification (363 ppm)(1). Indene was found at a concn of 15 ng/L in a canal to a harbor of a freshwater lake before any boat traffic was observed; after 1,293 boats passed through the canal, the concn of indene was 74 ng/L(2). Indene has been detected in wastewater effluents from the timber products industry at a concn of 8,252 ng/ul extract(3).

Soil Adsorption/MobilityBased on a measured log Kow of 2.92(2) and a regression derived equation(1), the Koc for indene can be estimated to be about 540(SRC). According to a suggested classification scheme(3), this Koc value suggests low mobility in soil.
Natural Pollution SourcesIndene is found in high-temperature coal tar at an average concn of 1 percent(1). It can be released to the environment in emissions from biomass combustion(2).
Atmospheric Concentrations · 1 item

In 1977, indene was qualitatively identified in the air of six industrial cities of the former USSR(1). Indene was qualitatively found in the air of three South African cities during the summer of 1975-winter of 1976(2). Indene was qualitatively identified in air taken at Homebush Bay, Australia on June 3, 1975(3). Indene was qualitatively identified in Paris air on October 24, 1972(4).

Safety data

F
8
OEB
A
OEL
TWA: 10 ppm (45 mg/m3)
PPE
Eyeshields, Faceshields, Gloves, type ABEK (EN14387) respirator filter
wgk
1
tsca
TSCA listed
rtecs
NK8225000
ridadr
UN 3295 3/PG 3
hs_code
2902 90 00
risk_code
10-65-36/37/38-20
Signal word
Danger
Symbol(GHS)
GHS02,GHS08
hazard_code
Xn
safety_code
23-24/25-62-37/39-26
hazard_class
3
Storage Class
3 - Flammable liquids
packing_group
III
Hazard statements
H226-H304
Limited Quantities
5.0 L (1.3 gallons) (liquid)
Excepted Quantities
Max Inner Pack (30g or 30ml) and Max Outer Pack (1Kg or 1L)
REACH Registrations
Active
Hazard Classifications
Asp. Tox. 1Flam. Liq. 3
Precautionary statements
P210-P233-P240-P241-P301+P310-P331
Hazardous Substances Data
95-13-6(Hazardous Substances Data)
General Manufacturing Information · 2 items

Petrochemical Manufacturing

1H-Indene: ACTIVE

Applications · 5 items

DescriptionIndene (also called 1H-Indene, C9H8) is a flammable polycyclic hydrocarbon. It is a colorless and aromatic smelling liquid. It is used in the synthesis of new C60 derivative (indene-C60 Bisadduct) and to prepare polyindene by the controlled cationic polymerization initiated with cumyl methyl ether/TiCl4 in CH2Cl2. Polyindene is further used to synthesize polyolefins. Indene is also used in the synthesis of istatins, in the production of indene/cumarone thermoplastic resins, and in the production of hydrocarbon resins. These industrial resins, also called indene-coumarone resins, are mainly consumed by the paints & coatings, rubber, and construction industries. It should be stored in a cool place. The container should be kept tightly closed in a dry and well-ventilated place. Containers which areopened must be carefully resealed and kept upright to prevent leakage. Indene is incompatible with strong oxidizing agents. Recommended storage temperature is 2 - 8°C. Indene is sensitive to light.

UsesPreparation of coumarone-indene resins, intermediate.

UsesPreparation of coumarone-indene resins

Uses1H-Indene is a building block that has been used in the synthesis of isatins. It was used in the synthesis of new C60 derivative, indene-C60 bisadduct. It was used in preparing polyindene by the controlled cationic polymerization initiated with cumyl methyl ether/TiCl4 in CH2Cl2.

General DescriptionA colorless liquid derived from coal tar. Fp: -2°C; bp:182°C. Density 0.997 g cm-3. Insoluble in water but soluble in organic solvents.

Upstream & downstream products

Upstream raw materials

Motor benzolheavy benzolColumn plateCOAL TARHeavy benzeneBenzofuran

Downstream products

1-IndanoneIndan1-AminoindanNaphthaleneAprindineINDANYL-1-CARBOXYLIC ACIDHomophthalic acidSulindac1-MethylnaphthaleneIndeloxazine hydrochlorideBenzofuranTriphenylphosphine hydrobromideIndan-2-amineANTHANTHRENE2-Bromoindene
Additional notes · 1 item

Definitionindene: A colourless flammable hydrocarbon,C9H8; r.d. 0.996; m.p.–1.8°C; b.p. 182.6°C. Indene is anaromatic hydrocarbon with a five-memberedring fused to a benzenering. It is present in coal tar and isused as a solvent and raw materialfor making other organic compounds.