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1,4-Benzenedicarbonyl dichloride is a highly reactive aromatic diacyl chloride commonly known as terephthaloyl chloride or terephthaloyl dichloride.
1,4-Benzenedicarbonyl dichloride is a white crystalline powder or colorless needle-like solid containing two carbonyl chloride groups in para positions on a benzene ring.
1,4-Benzenedicarbonyl dichloride is used primarily as a difunctional monomer for aramids, aromatic polyamides, polyarylates, polybenzoxazoles, membranes, fibers, films, coatings, and specialty organic intermediates.
CAS Number: 100-20-9
EC Number: 202-829-5
Molecular Formula: C₈H₄Cl₂O₂
Molecular Weight: 203.02 g/mol
SYNONYMS
Terephthaloyl Chloride, Terephthaloyl Dichloride, Terephthalic Acid Dichloride, Terephthalic Acid Chloride, Terephthalic Dichloride, Terephthalyl Dichloride, Terephthalyl Chloride, p-Phthaloyl Chloride, p-Phthaloyl Dichloride, para-Phthaloyl Chloride, para-Phthaloyl Dichloride, p-Phthalyl Dichloride, para-Phthalyl Dichloride, 1,4-Phthaloyl Dichloride, 1,4-Benzenedicarbonyl Chloride, Benzene-1,4-dicarbonyl Chloride, Benzene-1,4-dicarbonyl Dichloride, p-Benzenedicarbonyl Dichloride, para-Benzenedicarbonyl Dichloride, p-Phenylenedicarbonyl Dichloride, para-Phenylenedicarbonyl Dichloride, 1,4-Bis(chlorocarbonyl)benzene, 1,4-Bis(carbonyl chloride)benzene, Bis(4-carbonyl chloride)benzene, Benzene-1,4-dicarboxylic Acid Dichloride, Benzene-1,4-dicarboxylic Acid Chloride, Terephthalic Acid Diacid Chloride, Terephthalic Diacid Chloride, Terephthalic Acid Bis(acid chloride), Terephthaloyl Bis(chloride), TPC, TCl, TCL, TDC, Aromatic Diacyl Chloride, Aromatic Dicarbonyl Dichloride, para-Aromatic Diacid Chloride, Aramid Monomer, Aromatic Polyamide Monomer, Polyarylate Monomer, Polybenzoxazole Precursor, Interfacial-Polymerization Crosslinker, Membrane-Formation Diacyl Chloride, High-Purity Terephthaloyl Chloride, Polymer-Grade Terephthaloyl Chloride, Technical-Grade Terephthaloyl Chloride, Reagent-Grade Terephthaloyl Chloride, Synthesis-Grade Terephthaloyl Chloride, Analytical-Grade Terephthaloyl Chloride, C₈H₄Cl₂O₂, ClCOC₆H₄COCl, CAS 100-20-9, EC 202-829-5, PubChem CID 7488, NSC 41885, LXEJRKJRKIFVNY-UHFFFAOYSA-N
APPLICATIONS
1,4-Benzenedicarbonyl dichloride serves as a principal monomer for producing poly(p-phenylene terephthalamide) through reaction with p-phenylenediamine.
1,4-Benzenedicarbonyl dichloride forms rigid para-oriented amide linkages that support high molecular alignment and strong intermolecular association.
1,4-Benzenedicarbonyl dichloride supports preparation of aromatic polyamide resins used to manufacture high-strength and high-modulus fibers.
1,4-Benzenedicarbonyl dichloride requires nearly equimolar monomer balance and stringent moisture control to achieve high polymer molecular weight.
1,4-Benzenedicarbonyl dichloride functions as a diacid chloride component in high-performance aramid copolymers.
1,4-Benzenedicarbonyl dichloride reacts with combinations of aromatic diamines to modify fiber strength, modulus, compressive performance, processability, and solvent behavior.
1,4-Benzenedicarbonyl dichloride supports production of copolyamides containing benzimidazole, substituted phenylene, or other rigid aromatic units.
1,4-Benzenedicarbonyl dichloride contributes to fibers and reinforcement materials designed for protective equipment, cables, friction products, seals, and structural composites.
1,4-Benzenedicarbonyl dichloride serves as a reactive monomer in interfacial polymerization with aqueous diamines and polyamines.
1,4-Benzenedicarbonyl dichloride reacts rapidly at an organic–aqueous interface to form thin aromatic or semiaromatic polyamide layers.
1,4-Benzenedicarbonyl dichloride enables film formation at comparatively mild temperatures because acid chloride–amine reactions proceed readily.
1,4-Benzenedicarbonyl dichloride supports control of film thickness, crosslink density, morphology, and permeability through concentration and reaction-time adjustment.
1,4-Benzenedicarbonyl dichloride finds application in thin-film composite nanofiltration membranes for water desalting and solute separation.
1,4-Benzenedicarbonyl dichloride reacts with multifunctional amines to create selective polyamide surface layers on porous supports.
1,4-Benzenedicarbonyl dichloride supports membranes designed to reject salts, dyes, pharmaceuticals, and other dissolved organic contaminants.
1,4-Benzenedicarbonyl dichloride enables membrane performance to be modified through the amine structure, support chemistry, monomer concentration, and curing conditions.
1,4-Benzenedicarbonyl dichloride functions as a crosslinking monomer in organic-solvent nanofiltration membrane research.
1,4-Benzenedicarbonyl dichloride forms chemically resistant polyamide networks with suitable higher-functionality amines.
1,4-Benzenedicarbonyl dichloride supports membranes investigated for solvent recovery, pharmaceutical-intermediate concentration, and separation of dissolved organic compounds.
1,4-Benzenedicarbonyl dichloride contributes a rigid para-aromatic segment that can improve network compactness and solvent resistance.
1,4-Benzenedicarbonyl dichloride serves as a diacid chloride monomer for aromatic polyester and polyarylate synthesis.
1,4-Benzenedicarbonyl dichloride reacts with bisphenols and other aromatic diols to form rigid terephthalate ester linkages.
1,4-Benzenedicarbonyl dichloride supports preparation of heat-resistant polymers used in films, coatings, molded materials, and specialized engineering applications.
1,4-Benzenedicarbonyl dichloride enables polymer properties to be adjusted through selection of the diol, comonomer ratio, molecular weight, and polymerization method.
1,4-Benzenedicarbonyl dichloride functions as a rigid mesogenic building block in liquid-crystalline polyester research.
1,4-Benzenedicarbonyl dichloride provides linear para-oriented connectivity that promotes ordered polymer-chain structures.
1,4-Benzenedicarbonyl dichloride supports synthesis of materials exhibiting temperature-dependent transitions between crystalline, liquid-crystalline, and isotropic phases.
1,4-Benzenedicarbonyl dichloride contributes to polymers investigated for oriented films, fibers, composites, and heat-resistant components.
1,4-Benzenedicarbonyl dichloride serves as a monomer or comonomer in polybenzoxazole and polyhydroxyamide synthesis.
1,4-Benzenedicarbonyl dichloride reacts with aminohydroxy aromatic compounds to form cyclizable polymer precursors.
1,4-Benzenedicarbonyl dichloride supports subsequent thermal conversion of suitable precursor polymers into heat-resistant benzoxazole-containing structures.
1,4-Benzenedicarbonyl dichloride contributes to high-temperature films, fibers, aerogels, coatings, and gas-separation membrane materials.
1,4-Benzenedicarbonyl dichloride functions as a difunctional acylating reagent in specialty aromatic polyamide and polysulfonamide preparation.
1,4-Benzenedicarbonyl dichloride reacts with diamines to construct linear polymers containing repeated terephthalamide groups.
1,4-Benzenedicarbonyl dichloride supports development of polymers intended for heat resistance, dimensional stability, mechanical reinforcement, and chemical durability.
1,4-Benzenedicarbonyl dichloride enables copolymer design through partial replacement with other aromatic or aliphatic diacid chlorides.
1,4-Benzenedicarbonyl dichloride serves as a fine-chemical intermediate for preparing terephthalamides, terephthalate esters, hydrazides, and related bifunctional compounds.
1,4-Benzenedicarbonyl dichloride reacts with primary or secondary amines to form mono- or disubstituted aromatic amides.
1,4-Benzenedicarbonyl dichloride reacts with alcohols and phenols to form terephthalate esters having controlled symmetry and functionality.
1,4-Benzenedicarbonyl dichloride supports preparation of intermediates for medicinal chemistry, agrochemical research, ligands, dyes, and functional organic materials.
1,4-Benzenedicarbonyl dichloride functions as a crosslinking reagent for amino-functional molecules and macromolecules.
1,4-Benzenedicarbonyl dichloride can connect two nucleophilic sites through formation of stable amide bonds.
1,4-Benzenedicarbonyl dichloride supports preparation of protein-based microcapsules by interfacial crosslinking of accessible amino groups.
1,4-Benzenedicarbonyl dichloride enables capsule morphology and crosslinking density to be adjusted through pH, concentration, and reaction time.
1,4-Benzenedicarbonyl dichloride serves as an educational reagent for demonstrating interfacial polycondensation and rapid polymer-film formation.
1,4-Benzenedicarbonyl dichloride enables visible preparation of polyamide films or filaments when contacted with a compatible aqueous diamine phase.
1,4-Benzenedicarbonyl dichloride supports advanced instruction in step-growth polymerization, stoichiometric balance, diffusion control, and acid-chloride reactivity.
1,4-Benzenedicarbonyl dichloride requires professional laboratory containment because contact with moisture produces hydrogen chloride and corrosive reaction products.
1,4-Benzenedicarbonyl dichloride functions as a process-development reference for studying rapid acid chloride–amine and acid chloride–alcohol reactions.
1,4-Benzenedicarbonyl dichloride supports evaluation of mixing, heat removal, hydrogen chloride neutralization, molecular-weight development, and impurity formation.
1,4-Benzenedicarbonyl dichloride enables analytical comparison of monomer purity, hydrolysis, color-forming impurities, and polymerization performance.
1,4-Benzenedicarbonyl dichloride requires low water content and well-characterized purity when used as a quantitative polymerization or analytical reference.
1,4-Benzenedicarbonyl dichloride serves as a reference substance for infrared, mass-spectrometric, chromatographic, and thermal analysis.
1,4-Benzenedicarbonyl dichloride supports identity confirmation and quality control of polymer-grade aromatic diacid chloride materials.
DESCRIPTION
1,4-Benzenedicarbonyl dichloride is the systematic registry-style name of the compound commonly called terephthaloyl chloride.
The substance is identified by CAS Number 100-20-9 and EC Number 202-829-5.
Its molecular formula is C₈H₄Cl₂O₂.
Its molecular weight is approximately 203.02 g/mol.
The molecule contains a benzene ring bearing two carbonyl chloride groups.
The two carbonyl chloride groups occupy para or 1,4 positions on the aromatic ring.
This substitution pattern gives the molecule a rigid, linear, and comparatively symmetrical geometry.
Each carbonyl chloride group acts as a strongly electrophilic acylating site.
1,4-Benzenedicarbonyl dichloride is a difunctional acid chloride derived conceptually from terephthalic acid.
1,4-Benzenedicarbonyl dichloride is soluble in selected dry organic solvents capable of supporting acid-chloride processing.
Suitable solvent behavior depends on temperature, concentration, solvent polarity, and the absence of reactive functional groups.
Alcoholic, aqueous, or strongly nucleophilic solvents consume the acid chloride rather than functioning as inert media.
Solvent selection must also account for polymer solubility and hydrogen chloride management.
1,4-Benzenedicarbonyl dichloride reacts very rapidly with primary amines.
Reaction with diamines produces linear or crosslinked polyamides depending on monomer functionality and stoichiometry.
Hydrogen chloride is generated during each amide-forming substitution unless captured by a base or salt-forming medium.
Heat release and viscosity increase can be substantial during high-rate polymerization.
1,4-Benzenedicarbonyl dichloride reacts with diols and bisphenols to produce polyesters and polyarylates.
An acid acceptor is commonly used in solution or interfacial polymerization to neutralize hydrogen chloride.
Interfacial methods separate the nucleophilic monomer and diacid chloride into immiscible phases before reaction.
Film formation occurs where the two phases contact each other.
1,4-Benzenedicarbonyl dichloride provides para-oriented carbonyl linkages in the resulting polymer chain.
This geometry promotes chain rigidity and can support molecular orientation.
In aromatic polyamides, strong hydrogen bonding between amide groups further increases intermolecular cohesion.
Polymer properties nevertheless depend on the complete monomer system, molecular weight, processing, and morphology.
1,4-Benzenedicarbonyl dichloride polymerization performance is highly sensitive to monomer equivalence.
A small excess of acid chloride or diamine limits achievable molecular weight in conventional step-growth systems.
Hydrolysis products behave as stoichiometric defects or chain-terminating impurities.
Accurate assay and acid chloride equivalent determination are therefore essential.
1,4-Benzenedicarbonyl dichloride can be manufactured by chlorination of terephthalic acid.
Established routes include reaction with phosgene in the presence of a suitable catalytic system.
Other routes use thionyl chloride, triphosgene, or related chlorinating systems under controlled conditions.
The preferred route depends on scale, reagent availability, impurity control, corrosion, and waste treatment.
Phosgene-based manufacture can employ a dimethylformamide-associated catalytic complex.
Reaction conditions must control terephthalic acid conversion, catalyst stability, temperature, and unreacted starting material.
Process streams can contain formylbenzoyl chloride and dichlorotoluoyl chloride color-forming impurities.
Low concentrations of these impurities are important for color-sensitive high-performance polymers.
Alternative manufacturing routes can react terephthalic acid with thionyl chloride in a compatible dry solvent and catalyst system.
Excess chlorinating reagent and solvent are removed before final purification.
Reduced-pressure distillation or crystallization can provide material with high chemical purity.
Process selection must address sulfur-containing residues, catalyst removal, color, and corrosion.
Continuous-flow and microchannel processing has been investigated for terephthalic acid chlorination.
High heat- and mass-transfer rates permit precise control of short reaction times.
Continuous systems can improve utilization of phosgene or triphosgene and reduce reaction inventory.
Waste-gas absorption and containment remain essential because highly toxic chlorinating reagents may be involved.
High-purity 1,4-Benzenedicarbonyl dichloride is normally required for aramid polymerization.
Color-forming aldehyde-derived and chlorinated impurities can affect polymer appearance.
Residual terephthalic acid, monoacid chloride, water, and related phthaloyl chlorides can reduce molecular weight or alter processing.
Polymer-grade specifications may therefore be substantially tighter than general synthesis-grade specifications.
1,4-Benzenedicarbonyl dichloride quality control commonly includes appearance, assay, melting range, hydrolyzable chlorine, acidity, and moisture.
Chromatographic methods can determine related acid chlorides and organic color-forming impurities.
Infrared spectroscopy can confirm carbonyl chloride functionality and detect substantial hydrolysis.
Thermal analysis can characterize melting behavior and solid-state transitions.
1,4-Benzenedicarbonyl dichloride is combustible.
Finely divided powder can form an explosive mixture when dispersed in air.
Deposited dust can contribute to secondary explosions after an initial disturbance or ignition.
Closed systems and dust-explosion-resistant electrical equipment are recommended for bulk powder handling.
1,4-Benzenedicarbonyl dichloride has a reported flash point near 180°C.
Fire or strong heating produces toxic and corrosive fumes.
Dry sand, dry powder, or carbon dioxide is recommended for firefighting.
Water-containing extinguishing agents should not be applied directly because the substance reacts with water.
1,4-Benzenedicarbonyl dichloride reacts with strong oxidizing agents.
The material attacks many metals when moisture is present.
Wet metal equipment can therefore promote corrosion, contamination, leakage, and hydrogen chloride exposure.
Storage and process materials must be selected for dry acid-chloride service.
1,4-Benzenedicarbonyl dichloride is corrosive to the eyes, skin, respiratory tract, and gastrointestinal tract.
Inhalation can cause coughing, burning, labored breathing, and shortness of breath.
Severe exposure can cause swelling of the throat or pulmonary edema.
Respiratory symptoms may be delayed for several hours after exposure.
Direct skin contact can cause redness, pain, and chemical burns.
Eye contact can cause severe deep burns, pain, redness, and blurred vision.
Ingestion can cause abdominal pain, nausea, vomiting, diarrhea, shock, or collapse.
All significant exposures require prompt medical evaluation.
1,4-Benzenedicarbonyl dichloride should be stored dry and tightly closed.
The material should be separated from strong oxidizing agents and all sources of moisture.
International safety guidance advises against storage or transport in metal containers.
Packaging must prevent humidity ingress, breakage, corrosion, and accidental contact with water.
PROPERTIES
Chemical Name: 1,4-Benzenedicarbonyl dichloride
Common Name: Terephthaloyl chloride
Alternative Common Name: Terephthaloyl dichloride
IUPAC Name: Benzene-1,4-dicarbonyl chloride
CAS Number: 100-20-9
EC Number: 202-829-5
PubChem CID: 7488
NSC Number: 41885
Molecular Formula: C₈H₄Cl₂O₂
Condensed Structural Formula: ClCOC₆H₄COCl
Molecular Weight: 203.02 g/mol
Exact Molecular Weight: Approximately 201.9588 Da
InChIKey: LXEJRKJRKIFVNY-UHFFFAOYSA-N
Chemical Family: Aromatic diacyl chlorides
Chemical Classification: Difunctional aromatic acid chloride
Functional Groups: Two carbonyl chloride groups
Aromatic Substitution Pattern: Para or 1,4-substitution
Functionality: Two reactive acyl chloride groups per molecule
Physical State: Crystalline solid
Appearance: White powder or colorless needles
Odor: Pungent
Melting Point: Approximately 79.5–84°C
NIST Fusion Temperature: Approximately 356.1 K
Reported Solid-State Transition: Approximately 337.3 K
Boiling Point: Approximately 264–266°C
Density: Approximately 1.32 g/cm³
Vapor Pressure at 20°C: Approximately 320 Pa
Water Solubility: Reacts with water
Primary Hydrolysis Products: Terephthalic acid and hydrogen chloride
Calculated Log Pow: Approximately 0.88
Flash Point: Approximately 180°C
Combustibility: Combustible
Dust-Explosion Potential: Possible when fine particles are dispersed in air
Primary Chemical Function: Difunctional acylating reagent
Primary Polymer Function: Aromatic polyamide and aramid monomer
Additional Polymer Functions: Polyarylate, polyester, polybenzoxazole, polyhydroxyamide, membrane, and specialty polymer monomer
Principal Aramid Product: Poly(p-phenylene terephthalamide)
Primary Interfacial-Polymerization Function: Formation of polyamide selective layers and crosslinked films
Primary Fine-Chemical Function: Preparation of terephthalamides, terephthalates, hydrazides, and bifunctional aromatic derivatives
Reaction with Amines: Forms amides and releases hydrogen chloride
Reaction with Alcohols: Forms esters and releases hydrogen chloride
Reaction with Water: Rapid hydrolysis with formation of corrosive hydrogen chloride
Moisture Sensitivity: High
Skin Hazard: Causes severe burns
Eye Hazard: Causes severe eye damage and deep burns
Respiratory Hazard: Corrosive and capable of causing delayed pulmonary edema
Ingestion Hazard: Corrosive and potentially harmful
Chemical Stability: Stable only under suitably dry and controlled storage conditions
Incompatible Materials: Water, humid air, strong oxidizing agents, alcohols, amines, bases, and other nucleophilic materials
Metal Compatibility: Attacks many metals in the presence of water
Hazardous Decomposition Products: Hydrogen chloride, carbon oxides, corrosive organic fumes, and other toxic gases
Suitable Firefighting Media: Dry sand, dry powder, and carbon dioxide
Unsuitable Firefighting Media: Water, foam, and other hydrous agents
Recommended Storage: Dry, cool, tightly closed, and well-ventilated storage
Container Precaution: Avoid metal containers unless specifically protected and verified for dry acid-chloride service
Quality-Control Parameters: Appearance, assay, melting range, moisture, acidity, hydrolyzable chlorine, terephthalic acid, monoacid chloride, positional isomers, and color-forming impurities
Current Data Requirement: Confirm grade-specific purity, packaging, classification, transport requirements, occupational controls, and shelf life from current documentation.
FIRST AID
Inhalation:
Move the affected person immediately to fresh air.
Keep the person at rest in a half-upright position.
Do not allow physical exertion because pulmonary symptoms may be delayed and aggravated by activity.
Provide oxygen or assisted breathing only through trained personnel using suitable protective equipment.
Obtain immediate medical attention and maintain medical observation for possible delayed pulmonary edema.
Skin Contact:
Remove contaminated clothing, footwear, jewelry, and accessories immediately.
Brush away loose dry material carefully without dispersing dust.
Rinse the affected skin immediately with plenty of water or use an emergency shower.
Continue rinsing thoroughly while preventing contaminated runoff from contacting unaffected skin.
Obtain immediate medical attention because severe chemical burns may occur.
Eye Contact:
Rinse the eyes immediately with plenty of clean, gently flowing water.
Hold the eyelids open and move the eyes in all directions during irrigation.
Remove contact lenses when present and easy to do, then continue rinsing.
Continue irrigation for at least 20 minutes or until directed otherwise by medical personnel.
Obtain immediate ophthalmological attention because severe deep burns and permanent injury may occur.
Ingestion:
Rinse the mouth carefully with water.
Do not induce vomiting.
Give one or two glasses of water only when the person is fully conscious and can swallow safely.
Never give anything by mouth to an unconscious, drowsy, or convulsing person.
Obtain immediate medical attention because corrosive injury, shock, or collapse may occur.
Note to Physicians:
No substance-specific antidote should be assumed.
Provide supportive care and treat chemical burns and respiratory injury according to the patient’s clinical condition.
Monitor respiratory function for several hours because pulmonary edema may be delayed.
Assess the eyes, skin, mouth, throat, esophagus, gastrointestinal tract, cardiovascular condition, and oxygenation after substantial exposure.
Treat the incident as exposure to a moisture-reactive acid chloride capable of releasing hydrogen chloride.
Use current poison-center guidance and the grade-specific Safety Data Sheet as the primary medical references.
HANDLING AND STORAGE
Handling:
Handle 1,4-Benzenedicarbonyl dichloride in accordance with strict moisture-sensitive and corrosive-chemical procedures.
Review the current technical specification and Safety Data Sheet before opening, sampling, melting, transferring, or processing the material.
Avoid all contact with the skin, eyes, and clothing.
Do not breathe dust, vapor, aerosol, hydrogen chloride, smoke, or thermal-decomposition fumes.
Use enclosed charging, weighing, melting, reaction, filtration, transfer, and packaging systems wherever reasonably practicable.
Open containers only in a dry and effectively exhausted handling area.
Use clean, completely dry, and chemically compatible equipment.
Verify that reactors, transfer lines, valves, sampling tools, and receiving vessels contain no residual water.
Prevent exposure to humid air during sampling and transfer.
Use a dry inert-gas atmosphere where required to preserve acid chloride content and polymerization performance.
Add 1,4-Benzenedicarbonyl dichloride gradually to nucleophilic reaction mixtures under controlled agitation and temperature.
Provide adequate heat-removal capacity because reactions with amines, alcohols, bases, and water can be strongly exothermic.
Provide suitable hydrogen chloride capture, neutralization, or scrubbing systems.
Wash the hands, face, and exposed skin thoroughly after handling.
Do not eat, drink, or smoke in areas where 1,4-Benzenedicarbonyl dichloride is processed.
Ventilation:
Provide effective general ventilation and local exhaust ventilation.
Use local extraction at bag-emptying points, weighing stations, melting vessels, reactors, filters, dryers, mills, and packaging equipment.
Capture dust, hydrogen chloride, vapor, and decomposition fumes at their source.
Use corrosion-resistant ventilation ducts and gas-scrubbing equipment where acidic fumes may occur.
Use dust-collection equipment appropriate for combustible particulate material.
Use explosion-protected electrical equipment where airborne dust could form an explosive atmosphere.
Prevent recirculation of contaminated air unless it has been adequately filtered and treated.
Use suitable particulate and acid-gas respiratory protection when engineering controls cannot adequately limit exposure.
Use supplied-air or self-contained respiratory equipment for major spills, fires, confined spaces, or unknown concentrations.
Select respiratory protection through a documented occupational-exposure and hazard assessment.
Inspect exhaust systems, scrubbers, filters, and dust collectors regularly for corrosion, blockage, moisture ingress, and loss of performance.
Storage:
Store 1,4-Benzenedicarbonyl dichloride in tightly closed, moisture-resistant, and correctly labeled containers.
Keep the material in a cool, dry, secure, and well-ventilated location.
Protect 1,4-Benzenedicarbonyl dichloride from water, humid air, condensation, rain, steam, and wet cleaning systems.
Keep the material separated from strong oxidizing agents, alcohols, amines, bases, and other nucleophilic substances.
Keep the material away from open flames, sparks, hot surfaces, and uncontrolled heating.
Do not store or transport the material in unprotected metal containers.
Use containers and liners specifically verified for dry acid-chloride service.
Maintain an inert-gas blanket where required by the grade specification or process design.
Prevent water, dirt, rust, bases, alcohols, amines, and process residues from entering opened containers.
Reseal partially used containers immediately after sampling or transfer.
Use first-in, first-out stock rotation within the stated shelf life.
Inspect containers regularly for moisture ingress, corrosion, swelling, leakage, caking, hydrolysis, discoloration, or damaged seals.
Store the material in an area where accidental water contact and uncontrolled drainage can be prevented.
Spill and Leak Procedures:
Restrict access to the affected area and remove unnecessary personnel.
Evacuate the immediate area when a major release or strong acidic odor is present.
Eliminate ignition sources when this can be done safely.
Prevent contact between spilled material and water, foam, wet absorbents, or damp tools.
Provide effective local ventilation before beginning recovery operations.
Wear a chemical-protection suit, chemical-resistant gloves, eye protection, and respiratory protection suitable for particulates and acid gases.
Avoid sweeping methods that disperse fine particles into the air.
Carefully collect dry material with dry, non-sparking tools or a suitable hazardous-dust vacuum.
Place recovered material in dry, covered, chemically compatible plastic or lined containers.
Carefully collect residual contamination without applying uncontrolled water.
Do not wash the spill into drains, sewers, soil, groundwater, or surface water.
Perform decontamination or hydrolysis only through a controlled procedure developed for moisture-reactive acid chlorides.
Monitor the area for hydrogen chloride and airborne particulate contamination during cleanup.
Dispose of recovered material and residues through an authorized hazardous-waste route.
Handling Precautions:
Wear chemical-resistant gloves selected from documented permeation and compatibility data.
Use tightly fitting chemical goggles.
Wear a face shield in addition to goggles where powder, molten material, or reaction-mixture splashing is reasonably foreseeable.
Use chemical-resistant protective clothing, boots, sleeves, and an apron.
Use heat-resistant protective equipment when handling molten material.
Provide accessible eyewash and emergency-shower equipment near all major handling locations.
Keep emergency water physically separated from stored product while maintaining immediate access for exposed personnel.
Use suitable particulate and acid-gas respiratory protection during operations capable of generating dust or hydrogen chloride.
Ground and bond conductive equipment where static or combustible-dust hazards have been identified.
Inspect containers, seals, valves, heating systems, transfer equipment, filters, scrubbers, and dust collectors before use.
Confirm that every item of equipment is dry before contact with 1,4-Benzenedicarbonyl dichloride.
Do not use water, foam, or another hydrous agent to extinguish a fire involving the material directly.
Use dry sand, dry powder, or carbon dioxide in accordance with the emergency plan.
Do not mix 1,4-Benzenedicarbonyl dichloride with water, alcohols, amines, bases, strong oxidants, or unfamiliar reactants without a documented reaction-hazard assessment.
Review the current technical specification, Safety Data Sheet, certificate of analysis, occupational controls, transport rules, environmental requirements, and emergency procedures before production, storage, cleaning, or disposal.
