Chemical Profile

You’ll most commonly encounter this compound as **4‑Chlorobenzophenone**, though lab folks might reference it by several aliases:
- p‑CBP (the abbreviated go-to)
- p‑Chlorobenzophenone or para‑Chlorobenzophenone
- p‑Chlorodiphenylketone
- (4‑Chlorophenyl)phenyl‑methanone
- AKOS 90589 (for catalog hunters)

Key Identifiers:

- CAS No.: 134‑85‑0
- Formula: C₁₃H₉ClO
- Molecular Weight: 216.66 g/mol

Physical & Handling Characteristics

In practice, you’re looking at a **white to off-white crystalline solid** that’s surprisingly stable. A few specifics worth noting:
- Melts between 74–76°C (165–169°F)
- Boils at 195–196°C under reduced pressure (17 mmHg)
- Density: Roughly 1.15 g/cm³
- Flash Point: 143°C – handle accordingly!
- Storage Tip: Best kept sealed at 2–8°C to avoid moisture
What makes this material stand out is that *para*-chloro group tacked onto the benzophenone core. This little twist amplifies its electrophilic character, turning it into a remarkably versatile synthon.

Where You’ll See It in Action

Pharma Building Blocks

Synthetic chemists lean heavily on this ketone when crafting:
- Lipid-regulators like Fenofibrate
- Key intermediates for APIs needing rigid scaffolds
- Heterocyclic compounds (think antimalarials or CNS drugs)
Its stability during multi-step reactions explains why process chemists favor it.

Agrochemicals

Farm chemical developers tap it for:
- Next-gen pesticide precursors
- Herbicide/fungicide backbones
- Specialty growth regulators

Materials Science

Beyond pharma, it’s shaping advanced materials:
- Heat-resistant polymers (think aerospace components)
- UV-curable resins for coatings/adhesives
- Performance modifiers for engineering plastics

Dyes & Fine Chemicals

Also pops up in:
- High-value **dye intermediates**
- Friedel–Crafts acylations
- Custom derivatizations (that chloro group is your reaction handle!)

Why It Matters

Put simply, 4‑Chlorobenzophenone (CAS 134‑85‑0) is the **organic chemist’s multitool**. Its balanced reactivity profile – stable enough to store, yet primed for transformations – makes it indispensable everywhere from drug discovery pilot plants to polymer R&D labs. Whether you’re optimizing a crop protection agent or engineering thermoplastic composites, this crystalline workhorse delivers reliable performance.