3,3'-Dithiodipropionic acid
[CAS 1119-62-6]

Identification

• Classification: Chemical reagent >> Organic reagent >> Fatty acid
• Name: 3,3'-Dithiodipropionic acid
• Synonyms: 3-(2-carboxyethyldisulfanyl)propanoic acid
• Molecular Formula: C₆H₁₀O₄S₂
• Molecular Weight: 210.27
• CAS Registry Number: 1119-62-6
• EC Number: 214-284-0
• SMILES: C(CSSCCC(=O)O)C(=O)O

Properties

• Density: 1.5±0.1 g/cm³ Calc.^*
• Melting point: 155 - 158 °C (Expl.)
• Boiling point: 431.1±30.0 °C 760 mmHg (Calc.)^*
• Flash point: 214.5±24.6 °C (Calc.)^*
• Index of refraction: 1.592 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Serious eye damage	Eye Dam.	1	H318
Skin corrosion	Skin Corr.	1B	H314

chemBlink Chemical Story

3,3'-Dithiodipropionic acid, CAS 1119-62-6, is a symmetric disulfide-containing dicarboxylic acid. Its chemical story is best understood by looking at how its structure creates function rather than by treating the name as a simple catalog label. The molecule or material combines two carboxylic-acid arms joined by a central S-S bond, a combination that explains its relevance to redox-responsive linkers, polymer precursors and gold-surface chemistry.

The carboxyl groups provide handles for esterification and amidation, while the disulfide provides a chemically reducible breaking point. Sigma-Aldrich documents use as a precursor to 3-mercaptopropionic-acid-containing polythioesters and as a capping agent for introducing charge on gold nanoparticle surfaces. Reduction converts the central disulfide into thiol functionality.

This molecule illustrates how one bond can add responsiveness to an otherwise familiar dicarboxylic acid. The carboxyl groups build connections; the S-S bond determines whether those connections can later be broken under reducing conditions.

A broader lesson follows from this example. Chemical identity is only the starting point for performance. In polymers and surfactants, composition, molecular distribution and formulation can dominate behavior; in synthetic intermediates, the value may lie in transformations that occur only in later steps; in biologically active compounds, mechanism must be separated from clinical evidence. For 3,3'-Dithiodipropionic acid, the most reliable interpretation is therefore the one supported by its documented chemistry and literature rather than an assumed application.

The compound also illustrates why specialty chemicals often look more complicated than their job description suggests. Functional groups are selected to solve different parts of a practical problem: one region may provide reactivity, another solubility or interfacial affinity, and another stability or a controllable breaking point. Once those roles are separated, the long chemical name becomes a map of molecular design.

References:
TCI America, 3,3'-Dithiodipropionic Acid, CAS 1119-62-6; Sigma-Aldrich, 3,3'-Dithiodipropionic acid, application notes; Love JC et al. Chem Rev. 2005;105:1103-1169. DOI: 10.1021/cr0300789.

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