C.I. Solvent Blue 45 (CAS 37229-23-5) — Citrus N/A Note Fragrance Ingredient

ByThe Good Scents
Citrus · Floral

C.I. Solvent Blue 45

CAS 37229-23-5

Origin
synthetic
Note
N/A
IFRA
Professional use
Data as of: Apr 2026

What Is C.I. Solvent Blue 45?

C.I. Solvent Blue 45 is a synthetic dye primarily used in industrial applications such as inks, plastics, and coatings. Consumers may encounter it in colored packaging materials or specialty printing inks. While not commonly used in fragrances, its stability makes it valuable for coloring cosmetic products where lightfastness is required.

Safety Profile

PROFESSIONAL USE
Generally safeUse with awarenessProfessional use
⚠ Industrial chemical – not for consumer handling
✗ Not approved for direct skin contact in cosmetics
CAS
37229-23-5
Formula
Mixture
MW
Variable
Odor Family
Citrus · Floral
Layer 1 · Enthusiast

What Does C.I. Solvent Blue 45 Smell Like?

This compound is odorless in its pure form, serving exclusively as a colorant rather than a fragrance ingredient. Its molecular structure lacks volatile components that would contribute to scent perception. The material remains sensorially neutral even at elevated temperatures, making it suitable for applications where color stability is paramount without interfering with fragrance profiles.

Layer 2

Chemistry, Properties & Perfumer Guide

The Chemistry

C.I. Solvent Blue 45 belongs to the anthraquinone dye class, synthesized through halogenation and sulfonation of anthraquinone precursors. The chromophore consists of conjugated double bonds stabilized by electron-withdrawing groups, creating its intense blue coloration. Industrial production involves high-temperature reactions in sulfuric acid media, followed by purification through crystallization. The planar structure enables strong light absorption in the visible spectrum.

Physical & Chemical Properties

AppearanceBlue crystalline powder
SolubilitySoluble in organic solvents

Perfumer Guide

Note Position
N/A
Volatility
Non-volatile
Blending
Colorant only
ApplicationTypical %RangeNotes
Industrial Inks0.1-2%Up to 5%Heat-stable coloration
Plastics0.01-0.5%Up to 1%Polymer-compatible

Classic Accords

Tip: Use only in non-skin-contact applications where regulatory-approved colorants are required.

Alternatives & Comparisons

1
C.I. Solvent Blue 35 CAS 17354-14-2

Similar anthraquinone dye with slightly greener shade and better solubility in polar solvents.

2
Phthalocyanine Blue CAS 147-14-8

More lightfast organic pigment for applications requiring extreme durability.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

General reference only. Consult current IFRA Standards Library before formulating.

IFRA Status

Not regulated by IFRA as it is not a fragrance material.

GHS Classification

H315 Skin irritation H319 Eye irritation H335 May cause respiratory irritation

RIFM Assessment

Not evaluated by RIFM – classified as industrial chemical rather than fragrance ingredient.

Sustainability

Synthetic production raises concerns about halogenated waste streams. The dye’s persistence requires careful wastewater management in manufacturing facilities. While energy-intensive to produce, its high tinting strength reduces overall material usage compared to less potent colorants.

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References

  1. Color Index International (2021). Solvent Dyes Classification. Society of Dyers and Colourists.
  2. EPA Chemical Data Reporting (2016). Anthraquinone Dye Subcategory.

Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.

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