4-Ethylphenylboronic Acid CAS 63139-21-9: Properties, Uses, and Buying Guide
4-Ethylphenylboronic acid (CAS 63139-21-9) is an arylboronic acid used as a building block in organic synthesis, particularly in Suzuki–Miyaura cross-coupling to introduce a 4-ethylphenyl group into a target molecule. Its molecular formula is C8H11BO2, and its calculated molar mass is approximately 149.98 g/mol. For procurement, confirm the required assay, analytical documentation, packaging, and delivery schedule against your project needs rather than relying on the chemical name alone.
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Key Takeaways
- 4-Ethylphenylboronic acid is a para-substituted arylboronic acid with one boronic acid group and one ethyl substituent on the aromatic ring.
- Its principal synthetic role is as a coupling partner for forming carbon–carbon bonds; suitability depends on the reaction system and substrate.
- Evaluate suppliers using a batch-specific certificate of analysis, clearly defined specifications, suitable packaging, and realistic lead-time information.
- At a molar mass of 149.98 g/mol, 1 mmol corresponds to approximately 149.98 mg of pure compound. Adjust weighing calculations for the actual assay and handling requirements.
Who This Guide Is For
This guide is intended for procurement teams, medicinal and process chemists, contract research organizations, and manufacturers sourcing 4-Ethylphenylboronic acid for research or production workflows. It is also useful when comparing quotations for a specific CAS number and checking whether a supplier can provide the documentation required by your organization. The guidance focuses on identity, application fit, and sourcing decisions, not on prescribing a single reaction protocol.
Basic Concept and Chemical Context
Identity and structural features
The compound consists of a phenyl ring bearing an ethyl substituent at the 4-position and a boronic acid group attached directly to the aromatic ring. The para arrangement describes the relative positions of these two substituents. Its formula, C8H11BO2, contains 8 carbon atoms, 11 hydrogen atoms, 1 boron atom, and 2 oxygen atoms.
The boronic acid group is the functional handle commonly used in carbon–carbon bond-forming chemistry, while the ethyl group remains part of the resulting aryl fragment when the coupling proceeds as intended. In practical terms, the material offers a way to introduce a 4-ethyl-substituted aromatic unit into a more complex molecule. Reaction outcome is not guaranteed by reagent identity alone; substrate structure, catalyst, base, solvent, and operating conditions all matter.
Quick specification overview
| Item | Information | Procurement note |
|---|---|---|
| Product name | 4-Ethylphenylboronic acid | Check that the para-substituted isomer is specified. |
| CAS number | 63139-21-9 | Use CAS and product name together when requesting a quotation. |
| Molecular formula | C8H11BO2 | Confirm identity on the product documentation. |
| Calculated molar mass | Approximately 149.98 g/mol | Useful for stoichiometric calculations; not a measure of purity. |
Uses and Application Matching
Suzuki–Miyaura coupling and related synthesis
A common use for arylboronic acids is Suzuki–Miyaura cross-coupling with an appropriate organic halide or pseudohalide, typically under a catalyst and base system selected for the reaction. In this context, 4-Ethylphenylboronic acid can serve as the aryl donor for installing a 4-ethylphenyl group. The exact reaction conditions and conversion must be established for the specific coupling partner and process.
Potential applications include preparation of substituted biaryls and other intermediates used in discovery chemistry, materials research, and fine chemical synthesis. These are application areas for the chemical class, not a claim that this specific product is validated for every target or process. Before scaling a route, chemists should verify performance using their own substrates and analytical methods.
Match the grade and documentation to the task
For exploratory research, a buyer may prioritize identity confirmation, suitable assay information, and a practical pack size. For a process-development or manufacturing project, the purchasing specification may also need defined impurity limits, test methods, batch traceability, and change-notification expectations. These requirements should be agreed before an order is placed, because “high purity” without a stated method or acceptance limit may not answer a buyer’s quality question.
Do not assume that research-grade material automatically meets a regulated or validated manufacturing specification. Confirm intended use with your quality and regulatory teams, and request the applicable documents for the actual batch. Where a specific analytical method matters, state it in the inquiry and confirm whether the supplier can report results using that method.
Buyer Selection Framework
1. Confirm identity and acceptance criteria
Start with the full chemical name and CAS 63139-21-9, then specify the assay or purity requirement your process can accept. Ask how the supplier establishes identity and assay, and whether the certificate of analysis is batch-specific. If impurities or residual solvents affect downstream steps, include relevant limits in the inquiry instead of assuming they are covered by a general specification.
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2. Evaluate quantity, packaging, and handling
Request a quotation for the quantity you need and clarify the available pack sizes, packaging material, and any recommended storage or handling information. For materials that may be affected by moisture, air, or unsuitable storage conditions, follow the supplier’s product-specific guidance and your site’s chemical-handling procedures. Avoid transferring storage assumptions from a different boronic acid to this product without verification.
For mass calculations, the formula-based molar mass gives approximately 149.98 mg per 1 mmol of pure compound. A 10 mmol theoretical amount is approximately 1.50 g before adjustment for assay, weighing losses, or process excess. These are calculation references, not recommended reaction charge sizes.
3. Clarify commercial and delivery terms
Price, minimum order quantity, and lead time can vary with requested quantity, specification, packaging, and availability. Ask whether the quotation covers the requested documentation and delivery destination, and confirm the expected dispatch or delivery timing in writing. If your schedule is critical, discuss forecast demand and possible repeat-order requirements early rather than treating a single quotation as a supply commitment.
Supplier Evaluation Checklist
- Identity: Does the quotation clearly state 4-Ethylphenylboronic acid and CAS 63139-21-9?
- Quality: Are assay, test method, and acceptance criteria clearly described?
- Documentation: Can the supplier provide a batch-specific certificate of analysis and other documents your organization requires?
- Supply details: Are pack size, packaging, MOQ, lead time, and shipping terms confirmed?
- Communication: Does the supplier respond clearly to technical and commercial questions, including requests for a specification review?
A supplier should be assessed against your own qualification process, not solely on a product listing or a general statement about quality. Request the documents needed to make a decision and review them with the relevant technical, procurement, and quality stakeholders. For repeat supply, also clarify how changes to specification, manufacturing source, or documentation would be communicated.
Supplier Support from Maison Chemical
At Maison Chemical, we support B2B inquiries for 4-Ethylphenylboronic acid by discussing product identity, requested quantity, specification expectations, and destination requirements. We can review the documents available for the requested material and clarify commercial details such as packaging and lead time during quotation. Availability and documentation should be confirmed for each inquiry rather than assumed from a general product description.
To help us respond efficiently, include CAS 63139-21-9, target quantity, required assay or impurity limits, intended application, destination, and any documentation requirements. If you are comparing sources, share your acceptance criteria so the quotation can be assessed against the same basis. This makes it easier to identify specification gaps before purchase.
Conclusion: How to Buy 4-Ethylphenylboronic Acid
4-Ethylphenylboronic acid, CAS 63139-21-9, is a para-ethyl-substituted arylboronic acid used chiefly as a synthetic coupling building block. Its formula is C8H11BO2, and its calculated molar mass is approximately 149.98 g/mol. To select a suitable supply, verify the isomer and identity, define assay and documentation requirements, and confirm quantity, packaging, price, and delivery terms for your order.
Your next step is to prepare a purchase specification that states the required quantity, acceptance criteria, and documentation. Send those details to Maison Chemical for a B2B quotation and product-document review. Final suitability should be determined by your technical team using the intended application and your organization’s qualification procedures.