Sourcing 2-Fluoro-3-Iodo-5-Methylpyridine for LC Blends
Technical Specifications and Purity Grades for 2-Fluoro-3-iodo-5-methylpyridine in Liquid Crystal Synthesis
When sourcing 2-fluoro-3-iodo-5-methylpyridine (CAS 153034-78-7) for fluorinated liquid crystal blends, procurement managers must evaluate technical parameters beyond standard purity. This fluoroiodopyridine building block, also referred to as 2-fluoro-3-iodo-5-picoline, is critical for introducing lateral fluorine substituents that enhance dielectric anisotropy and reduce rotational viscosity in display-grade mixtures. Our industrial-grade material is supplied as a white crystalline powder with a minimum purity of 99.0%, verified by HPLC and GC analysis. However, for liquid crystal applications, the refractive index (nD20) and melting behavior are equally vital. The table below compares our standard pharmaceutical-grade product with a custom liquid-crystal-grade variant, which undergoes additional purification to minimize trace halogenated impurities that can cause scattering domains.
| Parameter | Standard Grade (INNO-2F3I5MP) | Liquid Crystal Grade (INNO-2F3I5MP-LC) |
|---|---|---|
| Purity (GC) | ≥99.0% | ≥99.5% |
| Appearance | White crystalline powder | White crystalline powder, free of visible specks |
| Melting Point | Please refer to batch-specific COA | Please refer to batch-specific COA |
| Refractive Index (nD20) | 1.587 (typical) | 1.587 ± 0.002 (batch-certified) |
| Individual Halogenated Impurity | ≤0.3% | ≤0.1% |
| Water Content (KF) | ≤0.5% | ≤0.2% |
This methylpyridine derivative is manufactured under a robust manufacturing process that ensures consistent industrial purity. For procurement teams, requesting a COA with refractive index and differential scanning calorimetry (DSC) data is essential to confirm batch suitability. Our quality assurance protocols include rigorous testing for halogen exchange byproducts, which can shift the nematic-isotropic transition temperature (TNI) in final blends. As a global manufacturer, we offer fast delivery and competitive bulk price options for ton-scale orders. For detailed specifications, refer to our product page: high-purity 2-fluoro-3-iodo-5-methylpyridine intermediate.
Refractive Index Drift and Melting Point Depression in Cyanobiphenyl Host Blends: Batch-to-Batch Variability
In fluorinated liquid crystal formulations, even minor batch-to-batch variations in 2-fluoro-3-iodo-5-methylpyridine can cause refractive index drift, compromising optical performance. Our field experience reveals that trace impurities, particularly 2-fluoro-5-methylpyridine (deiodinated byproduct), can lower the melting point of the pure compound by several degrees, leading to eutectic formation in cyanobiphenyl host mixtures. This melting point depression alters the clearing point and may induce smectic phase contamination. To mitigate this, we recommend that procurement managers specify a melting point range (e.g., 58–62°C) and request a DSC thermogram with each shipment. Additionally, the refractive index of the intermediate itself is not the sole concern; its contribution to the blend's extraordinary refractive index (ne) depends on molecular polarizability. A shift of 0.002 in the intermediate's nD20 can translate to a 0.005 change in the blend's birefringence, unacceptable for high-end displays. Our liquid-crystal-grade product is controlled within ±0.002, ensuring seamless integration as a drop-in replacement for existing supply chains. For insights on maintaining crystal integrity during transit, see our guide on bulk storage protocols for winter transit.
Trace Halogen Exchange During Storage: Impact on Nematic-Isotropic Transition Temperatures and Spectral Matching
A non-standard parameter often overlooked is the slow halogen exchange between iodine and chlorine or bromine from residual solvents or container liners. Over extended storage, particularly at elevated temperatures, 2-fluoro-3-iodo-5-methylpyridine can undergo Finkelstein-like reactions, generating 2-fluoro-3-chloro-5-methylpyridine or the bromo analog. These impurities, even at 0.1%, drastically shift TNI in multi-component mixtures because they alter the length-to-breadth ratio of the dopant. In one case, a batch stored for six months in a standard epoxy-lined drum showed a 2°C drop in TNI when blended at 5% w/w in a cyanobiphenyl host. To prevent this, we package our liquid-crystal-grade material in fluoropolymer-lined containers under inert gas. Procurement managers should also request NMR spectra (¹H and ¹⁹F) to verify halogen substitution integrity before blending. The ¹⁹F NMR signal for the 2-fluoro group is particularly sensitive to the adjacent halogen; any exchange is detectable as a shift from approximately -65 ppm (iodo) to -60 ppm (chloro). For further details on avoiding catalyst pitfalls in downstream reactions, read our article on Suzuki coupling optimization.
Bulk Packaging, Handling, and Supply Chain Reliability for Industrial Procurement
For industrial-scale procurement, packaging integrity directly impacts product quality. Our standard packaging includes 25 kg net weight in HDPE drums with inner fluoropolymer bags, or 210L steel drums for larger quantities. For ton-scale orders, we offer IBC totes with nitrogen blanketing. All shipments are accompanied by a batch-specific COA, safety data sheet (SDS), and, upon request, a certificate of origin. We maintain safety stock in multiple warehouses to ensure fast delivery within 7–14 days for most destinations. Our logistics team can arrange air, sea, or courier shipments, with temperature-controlled options for sensitive transit routes. As a global manufacturer of this chemical intermediate, we understand the criticality of supply chain continuity for display material producers. We offer blanket purchase orders with scheduled releases to align with your production cycles. For bulk pricing and availability, contact our sales team with your annual volume projections.
Frequently Asked Questions
What are acceptable refractive index tolerances for display-grade liquid crystal blends?
For most display applications, the refractive index of the pure intermediate should be controlled within ±0.002 of the certified value (typically 1.587). Tighter tolerances (±0.001) may be required for high-birefringence mixtures used in projection displays. Always request a batch-specific refractive index measurement at 20°C and 589 nm.
How can I verify halogen substitution integrity via NMR before blending?
We recommend ¹⁹F NMR spectroscopy as a rapid check. The 2-fluoro signal in 2-fluoro-3-iodo-5-methylpyridine appears as a doublet near -65 ppm (referenced to CFCl₃) with coupling to the ring protons. Any significant peak near -60 ppm indicates chloro substitution. ¹H NMR can also reveal the methyl singlet shift; the 5-methyl group resonates at approximately 2.3 ppm, and shifts >0.05 ppm may indicate impurity.
What are typical lead time expectations for spectrally matched lots?
For standard-grade material, lead time is 7–10 days from stock. For liquid-crystal-grade lots with spectral matching (refractive index and DSC verified), lead time is typically 2–3 weeks, as each batch undergoes additional testing. For large orders (>100 kg), we recommend a 4-week lead time to allow for dedicated production and quality control.
What is CAS number 1003 68 5?
CAS number 1003-68-5 corresponds to 5-methyl-2-pyridone, a different compound not related to our product.
What is the CAS number of 2 amino 3 methylpyridine?
The CAS number for 2-amino-3-methylpyridine is 1603-40-3. This is a distinct chemical from 2-fluoro-3-iodo-5-methylpyridine.
What is the melting point of 2 hydroxy 5 Methylpyridine?
2-Hydroxy-5-methylpyridine (CAS 1003-68-5) has a melting point of approximately 165–167°C. This information is provided for reference only and does not pertain to our fluoroiodopyridine product.
Sourcing and Technical Support
As a leading supplier of specialty heterocyclic intermediates, NINGBO INNO PHARMCHEM CO.,LTD. is committed to providing high-purity 2-fluoro-3-iodo-5-methylpyridine tailored for demanding liquid crystal applications. Our technical team can assist with method development for blend formulation and provide guidance on storage and handling to preserve spectral properties. We invite you to request a sample for evaluation and discuss your specific quality requirements. Ready to optimize your supply chain? Reach out to our logistics team today for comprehensive specifications and tonnage availability.