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Pigment Orange 13 is a widely used synthetic organic pigment belonging to the class of azo pigments.
It is known for its bright, reddish-orange hue and is commonly used in inks, paints, plastics, and coatings due to its good dispersibility and color strength.
CAS Number: 3520-72-7
Synonyms:
Permanent Orange G,C.I. Pigment Orange 13,Orange pigment 13,C.I. 21110,Benzidine Orange
Hostaperm Orange GR,Lithol Rubine Orange
Introduction
Pigment Orange 13 (PO13) is a widely used organic pigment belonging to the azo pigment family.
It is primarily known for its brilliant orange hue, excellent opacity, and good dispersion properties.
The pigment finds widespread application in coatings, plastics, printing inks, and textiles due to its vivid coloration and stability under various environmental conditions.
PO13 belongs to the class of monoazo pigments, specifically derived from arylide orange structures.
It is an important colorant in industrial and artistic applications, with unique characteristics that have made it a standard pigment for decades.
Chemical Identity and Structure
Chemical Name: 5-[(4-Chlorophenyl)azo]-2-hydroxy-N-phenyl-3-naphthalenecarboxamide
CAS Number: 3520-72-7
Molecular Formula: C32H24ClN5O3
Molecular Weight: ~561.02 g/mol
Structural Features: PO13 contains a monoazo linkage (-N=N-) connecting two aromatic systems: a chlorinated benzene ring and a naphthalene ring substituted with hydroxyl and amide groups.
The conjugated structure enables light absorption in the visible range, giving rise to its characteristic color.
The structure promotes good photostability and chemical resistance, making it suitable for demanding applications.
Synthesis and Manufacturing Process
The synthesis of Pigment Orange 13 involves diazotization and coupling reactions:
Diazotization: A primary aromatic amine such as 4-chloroaniline is treated with nitrous acid (generated in situ from sodium nitrite and hydrochloric acid) at low temperatures to form a diazonium salt.
Coupling Reaction: The diazonium salt is then reacted with an acetoacetanilide derivative or a naphthol compound in an alkaline medium, producing the final azo pigment.
Post-synthesis steps include filtration, drying, and sometimes surface treatment or grinding to enhance properties like dispersibility and gloss.
Physicochemical Properties
Appearance: Bright orange powder
Melting Point: Not well-defined due to decomposition
Solubility: Insoluble in water and most organic solvents
Oil Absorption: Moderate to high
Lightfastness: 6–7 on the Blue Wool Scale (moderate to good)
pH Stability: Stable in neutral to slightly alkaline conditions
Thermal Stability: Can withstand up to ~200°C in applications like plastics
Crystal Structure and Polymorphism
PO13 exists in several polymorphic forms, influencing its shade, dispersibility, and performance in various media. These crystalline forms result from different manufacturing and post-treatment conditions:
Alpha-form: Tends to have brighter shades
Beta-form: Slightly duller but more stable in some matrices
Controlling polymorphism is key to tailoring the pigment for specific end-uses.
Analytical Characterization Techniques
Several techniques are used to characterize PO13:
X-Ray Diffraction (XRD): Determines crystal structure and polymorphic forms
Fourier-Transform Infrared Spectroscopy (FTIR): Confirms functional groups
UV-Vis Spectroscopy: Measures absorbance spectrum and color intensity
Thermogravimetric Analysis (TGA): Assesses thermal stability
Scanning Electron Microscopy (SEM): Studies particle morphology
Colorimetric Properties and Applications
PO13 exhibits a brilliant orange hue with high tinting strength. The color is quantified using:
CIE Lab Color Space*: Provides numerical data for hue, chroma, and lightness
Masstone vs. Tint Tone: Evaluated in white bases to assess strength and tone
Applications include:
Plastics: Polyolefins, PVC, PS
Coatings: Architectural, industrial, automotive
Inks: Flexographic, gravure, and offset printing
Textiles: Pigment dyeing and printing
Stability and Weather Resistance
PO13 demonstrates moderate to high weather resistance, depending on the application medium and formulation additives:
UV Resistance: Good with stabilizers
Moisture Resistance: High due to low solubility
Chemical Resistance: Stable against acids and weak bases
Heat Resistance: Tolerates moderate processing temperatures
These properties can be enhanced with coatings or encapsulation technologies.
SAFETY INFORMATION ABOUT PIGMENT ORANGE 13
First aid measures:
Description of first aid measures:
General advice:
Consult a physician.
Show this safety data sheet to the doctor in attendance.
Move out of dangerous area:
If inhaled:
If breathed in, move person into fresh air.
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact:
Take off contaminated clothing and shoes immediately.
Wash off with soap and plenty of water.
Consult a physician.
In case of eye contact:
Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
Continue rinsing eyes during transport to hospital.
If swallowed:
Do NOT induce vomiting.
Never give anything by mouth to an unconscious person.
Rinse mouth with water.
Consult a physician.
Firefighting measures:
Extinguishing media:
Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas
Advice for firefighters:
Wear self-contained breathing apparatus for firefighting if necessary.
Accidental release measures:
Personal precautions, protective equipment and emergency procedures
Use personal protective equipment.
Avoid breathing vapours, mist or gas.
Evacuate personnel to safe areas.
Environmental precautions:
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Methods and materials for containment and cleaning up:
Soak up with inert absorbent material and dispose of as hazardous waste.
Keep in suitable, closed containers for disposal.
Handling and storage:
Precautions for safe handling:
Avoid inhalation of vapour or mist.
Conditions for safe storage, including any incompatibilities:
Keep container tightly closed in a dry and well-ventilated place.
Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Storage class (TRGS 510): 8A: Combustible, corrosive hazardous materials
Exposure controls/personal protection:
Control parameters:
Components with workplace control parameters
Contains no substances with occupational exposure limit values.
Exposure controls:
Appropriate engineering controls:
Handle in accordance with good industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
Personal protective equipment:
Eye/face protection:
Tightly fitting safety goggles.
Faceshield (8-inch minimum).
Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
Skin protection:
Handle with gloves.
Gloves must be inspected prior to use.
Use proper glove
removal technique (without touching glove's outer surface) to avoid skin contact with this product.
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices.
Wash and dry hands.
Full contact:
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
Splash contact
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
It should not be construed as offering an approval for any specific use scenario.
Body Protection:
Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection:
Where risk assessment shows air-purifying respirators are appropriate use a fullface respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls.
If the respirator is the sole means of protection, use a full-face supplied air respirator.
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Control of environmental exposure
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Stability and reactivity:
Chemical stability:
Stable under recommended storage conditions.
Incompatible materials:
Strong oxidizing agents:
Hazardous decomposition products:
Hazardous decomposition products formed under fire conditions.
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas.
Disposal considerations:
Waste treatment methods:
Product:
Offer surplus and non-recyclable solutions to a licensed disposal company.
Contact a licensed professional waste disposal service to dispose of this material.
Contaminated packaging:
Dispose of as unused product
