m-PEG5-CH2COOH

The carboxylic acid group enables efficient coupling to amines or alcohols, while the longer PEG4 spacer adds hydrophilicity and flexibility. It is typically supplied as a liquid or low-viscosity oil with purity in the 95% to 99%+ range. This compound serves as a practical building block for researchers requiring a one-sided PEG carboxylic acid in conjugation chemistry and process development.

Basic Information

CAS No.	16142-03-3
EC No.	Not available
Linear Formula	CH₃O(CH₂CH₂O)₄CH₂COOH
Molecular Weight	266.29 g/mol
Appearance	Colorless to pale yellow liquid or oil
Melting Point	Not available (typical reference)
Boiling point	Not available (typical reference)
Density	~1.12 g/mL at 20 °C (lit.)
Solubility	Soluble in water and polar organic solvents
Storage Conditions	Keep in a tightly closed container in a cool, dry and well-ventilated place. Protect from moisture and incompatible materials.
Chemical Structure

Key Applications

• PEG linker intermediate: The methoxy-terminated PEG4 chain with carboxylic acid end group serves as a monofunctional hydrophilic spacer for selective conjugation in bioconjugation workflows.

• Molecular linker intermediate: Functions as a building block for introducing a PEG carboxylic acid moiety into organic molecules during fine chemical synthesis.

• Bioconjugation research: Enables PEGylation of amines on proteins, peptides, or surfaces through amide bond formation using the terminal carboxylic acid group.

• Fine chemical intermediate: Applied in the preparation of specialty compounds where a methoxy-PEG carboxylic acid unit improves solubility and provides a conjugation handle.

• Process development: Supports route optimization and custom synthesis of PEGylated materials for pharmaceutical research and development projects.

• Consistent product quality: High-purity material with reliable batch consistency suitable for fine chemical synthesis and research applications.

• Flexible global supply: Support for laboratory, pilot-scale, and bulk quantities through established international logistics channels.

• SDS and COA support: Comprehensive product documentation including SDS and COA available to facilitate quality review and procurement processes.

• Packaging and technical service: Responsive technical communication and assistance with packaging options based on order requirements and product form.

Packaging and Storage

• Packaging: Available in small quantity sample bottles, 1 L to 25 L HDPE drums, and customized liquid packaging upon request.

• Storage: Store in tightly closed containers in a cool, dry, and well-ventilated area, protected from moisture and incompatible substances.

• Handling of opened containers: Minimize exposure to air and moisture after opening; reseal promptly and use contents within recommended timeframes.

• Bulk supply: Flexible packaging and delivery arrangements available for pilot-scale and commercial bulk orders.

Safety and Handling

• General handling: Follow good industrial hygiene and safety practices. Avoid unnecessary contact with skin, eyes, and clothing during handling and processing.

• Personal protection: Wear appropriate personal protective equipment including chemical-resistant gloves, safety goggles, and protective clothing as required.

• Documentation review: Always consult the latest Safety Data Sheet before handling, storage, transportation, or use of the material.

• Compatibility: Review compatibility with other process materials and avoid strong bases or conditions that may affect the carboxylic acid functionality.