1. Basic Information

• Chinese Name: Merrifield Resin, Chloromethylated Polystyrene Resin
• English Name: Merrifield Resin, Chloromethylated styrene‑divinylbenzene copolymer
• CAS No.: 55844‑94‑5
• MDL No.: MFCD00146406
• Solid Support: Polystyrene microspheres cross‑linked with 1% or 2% divinylbenzene (DVB)
• Functional Group: Benzylic chloromethyl group (‑CH₂Cl), available for nucleophilic substitution reactions.

2. Appearance & Typical Specifications

• Physical State: Off‑white to pale beige porous insoluble polymer beads
• Mesh Size: Popular grades: 100‑200 mesh, 200‑400 mesh
• Chlorine Loading Capacity: Commercial range 0.6～4.5 mmol/g, standard grades: 1.0‑1.5 mmol/g, 1.5‑2.5 mmol/g, 3.0‑4.0 mmol/g
• Swelling Property: Good swelling in DCM, DMF and NMP (4‑7 mL/g), compatible with Boc‑SPPS solvent systems.

3. Key Chemical Properties

1. Benzylic chloride reacts with carboxylate of Boc‑protected amino acid (cesium salt) under basic conditions to form a stable benzyl ester linkage for C‑terminal peptide anchoring.
2. The benzyl ester is resistant to repeated TFA treatments during Boc deprotection. Cleavage requires harsh superacid conditions (anhydrous HF or TFMSA); standard TFA cannot release the peptide.
3. Excellent mechanical and chemical stability under alternating acid‑base synthetic cycles.
4. Versatile synthetic intermediate: further derivatization (hydrolysis, amination, oxidation) to produce Wang resin, Rink Amide resin, trityl‑type resins and other functional solid supports.
5. Limitation: Aggressive cleavage reagents and special equipment are required, making it gradually replaced by mild‑cleavage Fmoc‑based resins for routine R&D.

4. Main Applications

1. Classical Boc‑strategy solid‑phase peptide synthesis (Boc‑SPPS) for C‑terminal carboxylic acid peptides.
2. Base raw material for manufacturing a full series of modified peptide synthesis resins (Wang, Rink, Trt resins).
3. Solid‑phase organic synthesis, heterocycle construction, polymer‑supported reagents and combinatorial chemistry library building.
4. Development of polymeric adsorbents and ion‑exchange materials.

5. Storage & Handling

• Storage: Keep tightly sealed, dry and protected from light; store at room temperature or 2‑8 °C to prevent hydrolysis.
• Amino acid loading protocol: Nucleophilic substitution with Boc‑amino acid cesium salt in DMF.
• Cleavage procedure: Special high‑risk cleavage system using anhydrous HF or TFMSA with dedicated HF equipment.
• Operate inside a fume hood; avoid inhalation of fine resin dust. HF and TFMSA are extremely corrosive and toxic; full specialized PPE is mandatory.

6. Safety Overview