Cyclopentanecarboxylic acid (3400-45-1) Physical and Chemical Properties
Cyclopentanecarboxylic acid
A cycloalkane-derived carboxylic acid used as a synthetic intermediate and building block for specialty chemical and active-ingredient synthesis.
| CAS Number | 3400-45-1 |
| Family | Cycloalkane carboxylic acids |
| Typical Form | Colorless liquid or viscous oil |
| Common Grades | EP |
Cyclopentanecarboxylic acid is a saturated monocyclic aliphatic carboxylic acid consisting of a cyclopentane ring bearing a single carboxyl functional group at a ring carbon. Structurally it is best described as a cyclopentyl-substituted methanoic acid (systematic IUPAC name: cyclopentanecarboxylic acid). The electronic structure is dominated by the localized carboxyl moiety, which provides a hydrogen-bond donor (–OH) and two hydrogen-bond acceptor sites (carbonyl and hydroxyl oxygen), while the cyclopentyl ring supplies a nonpolar hydrocarbon surface that moderates overall polarity and lipophilicity.
As a simple aliphatic carboxylic acid, acid–base behavior is typical for a monocarboxylic acid: it can donate a proton to form the cyclopentancarboxylate anion and forms stable salts with bases. The combination of the nonpolar ring and polar carboxyl group produces modest lipophilicity; the molecule partitions between aqueous and organic phases depending on pH (ionized form predominates in basic media, increasing aqueous solubility). Chemical stability is consistent with a saturated carboxylic acid: relatively robust to ambient conditions but reactive under standard functional-group transformations (esterification, amidation, conversion to activated derivatives, reduction of the carbonyl, etc.). Oxidative degradation is not pronounced for the saturated ring under mild conditions, but strong oxidants can oxidize the ring or cleave the carboxyl functionality.
Common commercial grades reported for this substance include: EP.
Basic Physical Properties
Density
No experimentally established value for this property is available in the current data context.
Melting Point
No experimentally established value for this property is available in the current data context.
Boiling Point
No experimentally established value for this property is available in the current data context.
Vapor Pressure
No experimentally established value for this property is available in the current data context.
Flash Point
No experimentally established value for this property is available in the current data context.
Chemical Properties
Solubility and Phase Behavior
Cyclopentanecarboxylic acid combines a hydrophobic cyclopentyl ring with a polar carboxyl group; as a result it exhibits appreciable solubility in polar organic solvents (alcohols, ketones, esters) and limited but pH-dependent solubility in water. In acidic media the neutral acid predominates and solubility in water is lower; in basic media the carboxylate anion forms and aqueous solubility increases markedly. The compound readily forms typical carboxylate salts with inorganic and organic bases and is compatible with common organic solvents used for derivatization chemistry.
Reactivity and Stability
Reactivity follows standard carboxylic-acid chemistry: the acid function undergoes condensation reactions (esterification, formation of amides), formation of activated derivatives (acid chlorides, mixed anhydrides), and reduction under appropriate conditions. Thermal decarboxylation is not a primary pathway for simple, saturated aliphatic carboxylic acids under mild conditions. The molecule is chemically stable under normal laboratory storage (ambient temperature, inert atmosphere) but will react with strong oxidizing agents and strong bases under forcing conditions. The substance is classified for hazards related to irritation: H315 (causes skin irritation), H319 (causes serious eye irritation), and H335 (may cause respiratory irritation) as reported for concentrated material; hazard classifications indicate the need to avoid contact and to control inhalation exposure.
Thermodynamic Data
Standard Enthalpies and Heat Capacity
No experimentally established value for this property is available in the current data context.
Molecular Parameters
Molecular Weight and Formula
- Molecular formula: C6H10O2
- Molecular weight: 114.14 \(\mathrm{g}\,\mathrm{mol}^{-1}\)
- Exact / monoisotopic mass: 114.068079557 (as reported)
LogP and Polarity
- XLogP3-AA (computed): 1.3 — indicates modest lipophilicity consistent with a nonpolar cyclopentyl ring balanced by a polar carboxyl group.
- Topological polar surface area (TPSA): 37.3 \(\text{Å}^2\) — consistent with a single carboxyl group providing hydrogen-bonding capacity.
- Hydrogen-bond donors: 1; hydrogen-bond acceptors: 2.
- Rotatable bond count: 1 — low conformational flexibility relative to larger aliphatic acids.
These parameters predict moderate partitioning into organic phases at neutral pH and increased aqueous solubility upon ionization.
Structural Features
- SMILES: C1CCC(C1)C(=O)O
- InChI: InChI=1S/C6H10O2/c7-6(8)5-3-1-2-4-5/h5H,1-4H2,(H,7,8)
- InChIKey: JBDSSBMEKXHSJF-UHFFFAOYSA-N
- Heavy atom count: 8; formal charge: 0; computed complexity: 92.7.
The molecule contains a single carboxyl-bearing stereochemically non-differentiated carbon framework (defined stereocenter count: 0). The carboxyl group is a single point of chemical functionality for derivatization and salt formation.
Identifiers and Synonyms
Registry Numbers and Codes
- CAS number: 3400-45-1
- EC number: 222-269-5
- UNII: Z6691VH94A
- ChEBI: CHEBI:230335
- ChEMBL: CHEMBL1902018
- DSSTox Substance ID: DTXSID70187610
- NSC number: 59714
- InChIKey: JBDSSBMEKXHSJF-UHFFFAOYSA-N
- SMILES: C1CCC(C1)C(=O)O
Synonyms and Structural Names
Reported synonyms include (selected): Cyclopentylcarboxylic acid; Cyclopentylmethanoic acid; Cyclopentanoic acid; Cyclopentanecarboxylic acid; Cyclopentane carboxylic acid; Cyclopentyl carboxylic acid; Cyclopentanoic Acid. Additional depositor-supplied names and legacy identifiers are present in supplier and registry listings.
Industrial and Commercial Applications
Representative Uses and Industry Sectors
Reported use classification includes cosmetics (surfactant). As a small aliphatic carboxylic acid with moderate lipophilicity, the compound is encountered as an intermediate or functional ingredient in specialty chemical formulations, including surfactant or emollient systems in personal-care applications. It can also serve as a building block in fine chemical and pharmaceutical synthesis where a cyclopentyl-containing acid functionality is required.
Commercial grades reported: EP.
Role in Synthesis or Formulations
Cyclopentanecarboxylic acid is primarily utilized as an acid-functional building block: it can be esterified or amidated to produce derivatives, converted to acid chlorides for acylation chemistry, or neutralized to form salts for formulation purposes. In formulations, the acid or its salts may contribute to pH adjustment, emulsion stabilization, or act as a precursor for surfactant-type derivatives. No concise application summary beyond these class-level roles is provided in the current data context.
Safety and Handling Overview
Acute and Occupational Toxicity
No numerically quantified acute toxicity endpoints (LD50, LC50) are available in the current data context. Hazard classifications reported for concentrated material indicate skin irritation (Skin Irrit. 2, H315), serious eye irritation (Eye Irrit. 2A, H319), and specific target organ toxicity — single exposure, respiratory tract irritation (STOT SE 3, H335). These classifications imply that dermal and ocular exposure can be harmful and that inhalation of vapors or aerosols should be controlled.
Precautionary statement codes reported include: P261, P264, P264+P265, P271, P280, P302+P352, P304+P340, P305+P351+P338, P319, P321, P332+P317, P337+P317, P362+P364, P403+P233, P405, and P501. Implementation of appropriate engineering controls, PPE (gloves, safety goggles, protective clothing), and local exhaust ventilation is recommended for occupational handling.
Storage and Handling Considerations
Store in tightly closed containers in a cool, well-ventilated area away from strong oxidizing agents and strong bases that could promote unwanted reactions. Handle to minimize skin and eye contact and avoid inhalation of vapors or aerosols. Use corrosion-resistant materials for storage and transfer equipment when handling concentrated material. For detailed hazard, transport and regulatory information, users should refer to the product-specific Safety Data Sheet (SDS) and local legislation.
