Why is PEG-300 specified by average molecular mass rather than a single molecular formula?

PEG-300 is a polyethylene glycol distribution, not one discrete molecule. Its grade is therefore assessed by average molecular mass and distribution-related controls, rather than a generic molecular formula or a single purity figure. The acceptance range should match the intended formulation or process.

Can PEG-300 directly replace PEG-200 or PEG-400?

Not automatically. These grades differ in average molecular mass and can differ in viscosity, handling and formulation response. A replacement should be compared against the relevant agreed specification and assessed in the intended system; CAS 25322-68-3 alone does not establish interchangeability.

Which PEG-300 controls are relevant when qualifying an alternative grade?

Confirm average molecular mass, hydroxyl value, water, acidity, colour, viscosity and any end-use-specific impurity limits, together with test methods. The appropriate acceptance criteria depend on the intended application and required documentation, not only on the product name or an average molecular-mass label.

Polyethylene Glycol 300 (PEG-300) CAS 25322-68-3

Polyethylene Glycol 300 (PEG-300, CAS 25322-68-3, EC/List No. 500-038-2) is a low-molecular-mass polyethylene-glycol distribution with an average molar mass around 300, not one discrete molecule. It is evaluated as a water-compatible solvent, carrier, humectant, plasticizing aid and process medium in industrial and formulated products. Grade suitability depends on the intended application and required standard. Confirm average molar-mass range, hydroxyl value, water, acidity, color, viscosity, relevant impurities, physical form, packaging and documentation for the offered grade. For a higher nominal molecular-mass polyethylene glycol with a more waxy physical form, PEG-1500 is a related grade to assess separately.

CAS: 25322-68-3
Synonyms: Polyethylene glycol 300; PEG 300; PEG-300; Macrogol 300; Polyoxyethylene glycol 300
Einecs: 500-038-2
Molecular Formula: H(OCH2CH2)nOH; molecular-weight distribution with average molar mass around 300
Grade: Confirm average molar-mass range, hydroxyl value, water, acidity, color, viscosity and relevant impurities
Package: Confirm current packaging, net weight, closure and destination requirements for the selected grade

Request a quote

Share:

Product Description

1 Product overview

2 Technical information

3 Handling and documentation

Product overview

Polyethylene Glycol 300 (PEG-300, CAS 25322-68-3, EC/List 500-038-2) is a low-molar-mass liquid polyether grade defined by an average molecular mass around 300, not by one discrete molecule. It is generally a clear, colorless, hygroscopic and viscous liquid that is miscible with water and many polar solvents. PEG-300 is used as a solvent or co-solvent, humectant, carrier, lubricant, plasticizer and formulation aid in personal-care, pharmaceutical-compatible and industrial systems. End-use suitability depends on the supplied grade: an industrial grade must not be presented as pharmacopeial, food or cosmetic grade without the relevant specification and compliance documents. Because PEG-300 contains a molecular-weight distribution, a generic 99% purity claim is not meaningful. Confirm the applicable average-mass range, hydroxyl value, water, acidity, color and viscosity on the current COA/TDS. Confirm current packaging, net weight, closure and destination requirements for the selected grade. Keep tightly closed to limit moisture uptake, clean spills promptly because they are slippery, and handle according to the current SDS.

Technical information

Product	Polyethylene Glycol 300 (PEG-300) CAS 25322-68-3
CAS number	25322-68-3
EC / list number	500-038-2
Molecular formula / identity	H(OCH2CH2)nOH; molecular-weight distribution with average molar mass around 300
Synonyms	Polyethylene glycol 300; PEG 300; PEG-300; Macrogol 300; Polyoxyethylene glycol 300
Grade	PEG-300; specify average molar mass, hydroxyl value, water, acidity, color and viscosity (not 99% single-compound purity)
Packaging	Confirm current packaging, net weight, closure and destination requirements for the selected grade

Handling and documentation

Specifications may vary by grade and batch. Confirm the current TDS, COA and SDS before purchase or use. Store and handle the product in accordance with the SDS and applicable site procedures.

FAQ - Technical & Supply Chain

Q:
Why is PEG-300 specified by average molecular mass rather than a single molecular formula?

A: PEG-300 is a polyethylene glycol distribution, not one discrete molecule. Its grade is therefore assessed by average molecular mass and distribution-related controls, rather than a generic molecular formula or a single purity figure. The acceptance range should match the intended formulation or process.
Q:
Can PEG-300 directly replace PEG-200 or PEG-400?

A: Not automatically. These grades differ in average molecular mass and can differ in viscosity, handling and formulation response. A replacement should be compared against the relevant agreed specification and assessed in the intended system; CAS 25322-68-3 alone does not establish interchangeability.
Q:
Which PEG-300 controls are relevant when qualifying an alternative grade?

A: Confirm average molecular mass, hydroxyl value, water, acidity, colour, viscosity and any end-use-specific impurity limits, together with test methods. The appropriate acceptance criteria depend on the intended application and required documentation, not only on the product name or an average molecular-mass label.

Ordering & Documentation

Key information for document requests, quotations, and supply planning.

Documents

COA, TDS, SDS/MSDS and packing details are available on request.

Quotation

Send the CAS number, grade, quantity, packing preference and destination.

Sample & Supply

Support is available for samples, trial orders, bulk and repeat supply.

Storage & Shipping

Product-specific conditions are confirmed before order.

Current Language

Change Language