Anhydrous 1-Bromo-5-Fluoropentane CAS 407-97-6 Grignard Grade Low Water

Water is the enemy in this one. Fifty parts per million is enough to leave a haze of magnesium hydroxide, eat into your yield and block the filter. We dry over molecular sieve under argon, check by Karl Fischer, and fill under the same blanket, so the figure on the certificate is the figure in your flask.

The other number worth watching is peroxide. An alkene-free alkyl halide does not form peroxides as fast as an alkene, but the bottle still sits in a store for months, and peroxides change the initiation behaviour. We hold this grade at 20 mg/kg or below and say so on the label.

• Water 50 ppm maximum by Karl Fischer: clear Grignard solution, no hydroxide haze, no lost reagent
• Peroxide 20 mg/kg maximum: predictable initiation with magnesium or lithium
• Argon filled with septum caps on 1 kg: cannula transfer without opening to air
• Dibromoalkane under 0.5%: the dihalide would consume two equivalents of metal and skew the charge
• Low free alcohol: no competing proton source during reagent formation
• Drum headspace sieve option: dryness survives a long voyage, not just the QC bench

Preparing 5-fluoropentylmagnesium bromide or the corresponding lithium reagent, and any organometallic step where the water budget is already tight and an extra drying step is not practical.

Transfer by cannula or syringe through the septum. Initiate with a small portion plus a crystal of iodine if the magnesium is old, then add the rest at a rate that keeps reflux without running away.

1 kg amber glass with septum cap, 5 kg lined cans, 25 kg drums with a headspace sieve for plant scale. Argon filled, labelled with the water content measured at release.

Store under argon between 5 and 25 degrees C, away from ignition sources, with earthed containers when decanting.

COA reports assay, water by Karl Fischer, peroxide value, free alcohol, dibromoalkane, colour and density, with the GC trace. Retention sample kept 12 months under argon.

We can add a moisture barrier bag to the drum or supply a small argon cylinder with the first order so you can re-blanket after each use.