L(-)-Camphorsulfonic Acid – CAS 35963-20-3

What Is L(-)-Camphorsulfonic Acid?

L(-)-Camphorsulfonic acid, also known as (1R)-(-)-10-camphorsulfonic acid or L(-)-CSA, is an optically active organic sulfonic acid with CAS number 35963-20-3.

Its rigid camphor-derived chiral framework and strongly acidic sulfonic acid group make it useful as a chiral resolving agent, pharmaceutical synthesis reagent, acid catalyst and specialty chemical intermediate.

L(-)-CSA is particularly valuable for resolving racemic amines. It can react with the two enantiomers of a basic compound to form diastereomeric salts with different crystallization or solubility behavior. This difference may allow one salt to be separated by selective crystallization.

AOZUN supplies high-purity L(-)-camphorsulfonic acid for research, process development and industrial synthesis. Suitability for a specific pharmaceutical or regulated application must be established through customer qualification.

L(-)-Camphorsulfonic Acid Identification

The CAS number, specific optical rotation and chemical form should always be checked together. Product names alone may be unreliable because some supplier pages use inconsistent L/D, R/S and positive/negative rotation terminology.

Why Choose AOZUN as Your L(-)-Camphorsulfonic Acid Supplier?

AOZUN supports buyers that require consistent chemical identity, controlled optical rotation and industrial supply documentation.

Our supply advantages include:

• High-purity L(-)-CSA for industrial synthesis

• Defined CAS number and enantiomeric form

• Controlled specific optical rotation

• White to off-white crystalline appearance

• Moisture and inorganic-impurity control

• Batch-specific Certificate of Analysis

• SDS and technical-document support

• Sample quantities for laboratory qualification

• Industrial packaging options

• International shipping support

• Assistance distinguishing L(-), D(+) and DL forms

When requesting a quotation, provide the intended application, required specification, order quantity, destination and any special limits for water, iron, sulfate or residual solvents.

Typical L(-)-Camphorsulfonic Acid Specifications

The following table represents a typical commercial specification. The approved AOZUN sales specification and batch Certificate of Analysis must govern each transaction.

Specific optical rotation is meaningful only when the test temperature, wavelength, solvent and concentration are defined. These conditions should be stated on the specification or COA.

Assay results obtained by HPLC, acid-base titration or another method should not automatically be treated as equivalent. Buyers should confirm the analytical method when comparing suppliers.

What Is L(-)-Camphorsulfonic Acid Used For?

Chiral Resolution of Racemic Amines

The best-known application of L(-)-CSA is the resolution of racemic amines and other basic compounds.

When an enantiopure acid reacts with a racemic base, it can produce two diastereomeric salts. Unlike enantiomers, these salts may have different physical properties, including:

• Solubility

• Crystallization rate

• Crystal form

• Melting behavior

• Filtration performance

These differences can sometimes be used to isolate one salt selectively. The resolved base may subsequently be released from the isolated salt using a suitable downstream process.

Resolution performance is substrate-specific. L(-)-CSA will not provide efficient separation for every racemic amine, so solvent and crystallization screening are necessary.

Pharmaceutical Intermediates and Process Chemistry

L(-)-CSA is used in selected pharmaceutical processes as:

• A chiral resolving agent

• A salt-forming acid

• An organic synthesis reagent

• A process intermediate

• A stereochemical control reagent

• A strong organic acid catalyst

It may be used to form camphorsulfonate salts, also called camsilate or camsylate salts.

Use of industrial L(-)-CSA in a pharmaceutical process does not make the material an API, excipient or pharmacopeial product. The buyer must establish the required quality standard, impurity controls, traceability and regulatory documentation.

Formation of Camsilate Salts

L(-)-Camphorsulfonic acid can react with suitable basic compounds to form camphorsulfonate salts.

Salt formation may change properties such as:

• Crystallinity

• Hygroscopicity

• Thermal behavior

• Solubility

• Chemical stability

• Filtration characteristics

• Handling behavior

These effects cannot be predicted from the acid alone. Salt screening, solid-form characterization and stability testing should be completed for each target compound.

Organic Synthesis and Acid Catalysis

As a strong organic sulfonic acid, L(-)-CSA may be evaluated as an acid catalyst or acidic reagent in selected organic transformations.

Potential uses include:

• Acid-catalyzed synthesis

• Protection and deprotection steps

• Rearrangement reactions

• Condensation reactions

• Preparation of chiral intermediates

• Synthesis of camphorsulfonate derivatives

Reaction compatibility depends on the substrate, solvent, temperature and other reagents. Laboratory evaluation is required before scale-up.

Chiral Reagent and Analytical Chemistry

L(-)-CSA may be used as:

• A chiral counterion

• A derivatization reagent

• A chiral recognition reagent

• An ion-pairing component

• A reference material for method development

• A reagent in stereochemical research

Analytical applications may require tighter limits for assay, optical purity, water and trace impurities than standard industrial synthesis applications.

Specialty Polymers and Functional Materials

Camphorsulfonic acids are also investigated as acidic dopants in conducting polymers such as polyaniline.

The chiral form may help introduce a chiral environment into selected functional materials. This is a specialized research and materials application, and performance depends on polymer structure, doping conditions and processing method.

How Does L(-)-CSA Resolve a Racemic Amine?

Chiral resolution by salt formation generally involves four principles.

1. Acid–Base Salt Formation

L(-)-CSA donates a proton to a basic amine. The resulting ammonium camphorsulfonate is an ionic salt.

2. Formation of Diastereomeric Salts

The two enantiomers of the racemic amine form two different diastereomeric salts with the single enantiomer of L(-)-CSA.

3. Selective Crystallization

If the two salts have sufficiently different solubility or crystallization behavior, one may crystallize preferentially from the selected solvent system.

4. Recovery of the Resolved Compound

The isolated salt can be treated using an appropriate process to release the enriched free base. The enantiomeric ratio, yield and chemical purity must then be measured.

Successful resolution depends on more than the identity of the resolving agent. Important variables include:

• Solvent composition

• Water content

• Acid-to-base molar ratio

• Concentration

• Addition sequence

• Temperature profile

• Cooling rate

• Mixing

• Seeding

• Crystallization time

• Washing conditions

Optimization should be based on experimental screening rather than a universal recipe.

L(-), D(+) and DL Camphorsulfonic Acid: What Is the Difference?

L(-)-CSA and D(+)-CSA are enantiomers. They have many similar non-chiral physical properties but interact differently with chiral substrates.

DL-camphorsulfonic acid contains both enantiomers and normally cannot provide the same resolving function as an enantiopure grade.

The different forms should not be substituted without process evaluation.

Does L(-) Always Mean the Same as (1R)-(-)?

For the commercial material identified by CAS 35963-20-3, L(-)-camphorsulfonic acid is commonly identified as (1R)-(-)-10-camphorsulfonic acid.

However, the letters L and D do not universally establish absolute R/S configuration for all chemicals. The plus and minus signs indicate the experimentally observed direction of optical rotation and also do not independently define absolute configuration.

For reliable purchasing, specify:

• Complete chemical name

• CAS number

• Required optical rotation

• Rotation test conditions

• Assay

• Chemical form

• Required supporting documents

Is Optical Rotation the Same as Enantiomeric Purity?

No. Specific optical rotation is an important identity and consistency test, but it is not always a complete measurement of enantiomeric purity.

The measured value may be affected by:

• Concentration

• Solvent

• Temperature

• Wavelength

• Water content

• Chemical impurities

• Instrument calibration

• Test procedure

If stereochemical purity is critical, the buyer should consider an appropriate chiral analytical method in addition to specific rotation.

Possible methods include chiral HPLC, chiral GC or another validated stereochemical method suitable for the material.

How to Select the Right L(-)-Camphorsulfonic Acid Grade

Confirm the CAS Number and Enantiomer

Verify that the required product is CAS 35963-20-3. Do not order solely by the terms camphorsulfonic acid or CSA because these names may also refer to the D(+) or DL forms.

Compare Specific Rotation Under Identical Conditions

Two rotation results should only be compared when concentration, solvent, temperature and wavelength are the same.

A value such as −21° without defined test conditions is incomplete for supplier qualification.

Review the Assay Method

Ask whether the assay is measured by:

• HPLC

• Neutralization titration

• Dry-basis calculation

• Another validated method

A titration result measures acid content but may not provide the same impurity information as a chromatographic assay.

Control Water and Loss on Drying

Water can affect active-content calculations, salt stoichiometry, dissolution and crystallization behavior.

Loss on drying and Karl Fischer water are different tests and may produce different results. Confirm which one controls the process.

Review Iron, Sulfate and Inorganic Residues

Trace metals and inorganic residues may influence:

• Product color

• Reaction behavior

• Downstream purification

• Catalyst-sensitive processes

• Pharmaceutical impurity profiles

Customers with sensitive processes should provide application-specific limits.

Define Residual-Solvent Requirements

A general statement such as “residual solvents comply” is not sufficiently specific for a regulated process.

The buyer should define:

• Which solvents must be tested

• The applicable limits

• The analytical method

• Whether every batch requires testing

Check the Anhydrous or Hydrated Form

The molecular formula C10H16O4S and molecular weight 232.30 describe anhydrous L(-)-CSA.

If a supplier lists C10H18O5S or a molecular weight close to 250.31, the product may be presented as a monohydrate or the product data may be inconsistent. Confirm the actual chemical form, water specification and basis of assay before ordering.

Recommended L(-)-CSA Qualification Procedure

Step 1: Review Supplier Documents

Compare the specification, sample COA, SDS, manufacturing information and analytical methods.

Step 2: Confirm Chemical Identity

Verify the CAS number, appearance, assay and an appropriate identity test such as IR or another validated method.

Step 3: Confirm Stereochemical Identity

Measure specific rotation under the same conditions stated in the purchase specification.

Use a suitable chiral method when enantiomeric purity is a critical process attribute.

Step 4: Evaluate Solubility

Test the material in the proposed process solvent at the required concentration and temperature.

Record:

• Dissolution time

• Solution clarity

• Color

• Undissolved matter

• Temperature effects

• Precipitation during cooling

Step 5: Conduct Resolution or Salt-Formation Trials

For a chiral-resolution process, evaluate salt formation and crystallization using small-scale experiments.

Measure:

• Isolated yield

• Chemical purity

• Enantiomeric ratio

• Salt stoichiometry

• Crystal form

• Filtration rate

• Mother-liquor losses

• Reproducibility

Step 6: Compare Multiple Batches

Where the application is sensitive, qualify more than one production batch before commercial approval.

Step 7: Complete a Controlled Scale-Up

Review heat generation, mixing, addition sequence, crystallization, filtration and containment before increasing batch size.

Solubility and Process Considerations

L(-)-Camphorsulfonic acid is soluble in water and is also compatible with selected polar organic solvents.

Actual solubility depends on:

• Solvent identity

• Water content

• Temperature

• Concentration

• Other dissolved compounds

• Whether the free acid or a salt is present

For resolution processes, maximum solubility is not always desirable. Effective separation often depends on obtaining a useful solubility difference between two diastereomeric salts.

Solvent selection should therefore consider both salt formation and selective crystallization.

Packaging and Supply

Typical industrial packaging may include:

• Sealed bags with protective liners

• Fiber drums with inner liners

• 25 kg industrial drums, subject to confirmation

• Customer-agreed packaging for qualified orders

Final packaging depends on order size, destination, transportation requirements and customer specifications.

Partially used containers should be resealed promptly to prevent moisture absorption and contamination.

Storage and Stability

Store L(-)-camphorsulfonic acid:

• In tightly closed original packaging

• In a cool, dry and well-ventilated area

• Away from moisture and direct sunlight

• Away from incompatible bases and reactive materials

• In corrosion-resistant or suitably lined packaging

• Under the conditions stated in the current AOZUN SDS

Avoid prolonged exposure to humid air. Do not return unused or contaminated material to the original container.

Shelf life should be based on the product label, approved specification and storage conditions rather than a general website statement.

Safe Handling

L(-)-camphorsulfonic acid is a corrosive acidic material and may cause severe skin burns and serious eye damage.

Recommended controls include:

• Chemical-resistant gloves

• Protective clothing

• Safety goggles

• Face protection where splash or dust exposure is possible

• Suitable local ventilation

• Dust-control measures

• Accessible emergency washing facilities

• Properly trained personnel

Avoid breathing dust and prevent direct contact with skin and eyes.

Transport classification may depend on product form, packaging, jurisdiction and the current supplier SDS. Always use the latest AOZUN SDS and shipping documentation when arranging transportation.

This product page is not a replacement for the Safety Data Sheet.

Quality and Supply Documents

Available documents should be confirmed when requesting a quotation. Depending on the order and destination, documentation may include:

• Batch-specific Certificate of Analysis

• Safety Data Sheet

• Technical Data Sheet

• Commercial invoice

• Packing list

• Country-of-origin document

• Transport documentation

• Manufacturing statement

• Residual-solvent statement

• Allergen or animal-origin statement when applicable

• Regulatory information required for the destination market

Application-specific documentation should be agreed before the purchase order is issued.

Information Required for a Quotation

To receive an accurate quotation, provide:

• Product name and CAS number

• Required assay

• Required specific rotation and test conditions

• Water or loss-on-drying limit

• Limits for iron, sulfate or residue on ignition

• Residual-solvent requirements

• Required quantity

• Annual estimated consumption

• Intended application

• Packaging requirement

• Destination port or delivery address

• Required Incoterm

• Required quality and shipping documents

• Sample requirement

Frequently Asked Questions

What is the CAS number of L(-)-camphorsulfonic acid?

The CAS number of L(-)-camphorsulfonic acid, commonly identified as (1R)-(-)-10-camphorsulfonic acid, is 35963-20-3.

What is its correct molecular formula?

The molecular formula of anhydrous L(-)-camphorsulfonic acid is C10H16O4S, and its molecular weight is approximately 232.30 g/mol.

What is the main use of L(-)-camphorsulfonic acid?

Its principal industrial use is as a chiral resolving agent for racemic amines and other basic compounds. It is also used in salt formation, pharmaceutical process chemistry, organic synthesis and specialty materials research.

How does it separate enantiomers?

It reacts with a racemic base to form two diastereomeric salts. If the salts have different solubility or crystallization behavior, one may be isolated selectively.

Is L(-)-CSA the same as D(+)-CSA?

No. They are opposite enantiomers with different CAS numbers and opposite optical rotation. L(-)-CSA has CAS number 35963-20-3, while D(+)-CSA commonly has CAS number 3144-16-9.

Can DL-camphorsulfonic acid replace L(-)-CSA?

Not in a chiral-resolution process. DL-camphorsulfonic acid is racemic and normally cannot provide the same stereochemical discrimination as an enantiopure resolving agent.

What specific rotation should L(-)-CSA have?

A common commercial range is approximately −21.0° to −23.0°. The solvent, concentration, temperature and wavelength must be defined before results are compared.

Does specific rotation prove enantiomeric purity?

Not by itself. It is useful for identity and batch consistency, but a validated chiral analytical method may be required when enantiomeric purity is critical.

Is L(-)-camphorsulfonic acid soluble in water?

Yes. It is soluble in water. Solubility in an actual process will depend on concentration, temperature, other components and whether a salt has formed.

Is AOZUN L(-)-CSA pharmaceutical grade?

L(-)-CSA may be supplied for pharmaceutical synthesis and intermediate applications, but the term pharmaceutical grade should only be used when a defined quality standard, manufacturing system and supporting documentation have been agreed.

It should not automatically be described as an API or pharmaceutical excipient.

What are the most important quality indicators?

The key indicators are assay, specific optical rotation, water or loss on drying, chemical identity, appearance, melting behavior and application-relevant impurities.

How should the product be stored?

Keep it tightly sealed in a cool, dry and well-ventilated place. Protect it from moisture, sunlight, contamination and incompatible substances. Follow the current product SDS.

Can AOZUN provide a sample?

Sample availability can be confirmed according to grade, destination and required quantity. Include the intended application and specification when requesting a sample.

Request an L(-)-Camphorsulfonic Acid Sample or Quotation

AOZUN supplies L(-)-camphorsulfonic acid, CAS 35963-20-3, for chiral resolution, pharmaceutical intermediates, organic synthesis and specialty chemical applications.

Contact AOZUN with your required specification, quantity, application, packaging and delivery destination. Our team will confirm the available grade, batch documentation, sample availability and commercial terms.