Synhipol® UV-710B (4-Butoxy-2,2,6,6-tetramethylpiperidin-1-oxyl, CAS 154186-23-9) is a high‑performance nitroxide radical inhibitor engineered to suppress unwanted polymerization during the production, separation, refining, and storage of reactive monomers.
Compared to traditional 4‑Hydroxy‑TEMPO (polymerization inhibitor UV‑701, CAS 2226‑96‑2), Synhipol® UV-710B delivers superior oil solubility, longer protection, lower corrosion, and extended equipment service life.
Whether you are distilling acrylic acid, storing styrene, or refining acrylate monomers, UV‑710B provides more efficient, more stable, and more cost‑effective polymerization inhibition.
Both 4‑Hydroxy‑TEMPO and 4‑Butoxy‑TEMPO terminate chain growth by capturing radicals to form C–ON bonds. However, the electron‑donating effect of the butoxy group gives UV‑710B three distinct advantages:
Slightly higher N–O• spin density – more active radical trapping sites
20–30% increase in radical trapping rate constant (k_trap)
Hydrophobic butoxy chain – reduces partitioning into aqueous phases, maintaining higher actual concentration in the organic phase
Industrial validation:
| Monomer System | Inhibitor (50 ppm, 120°C) | Induction Period | Fouling Rate (mg/100 mL·h) |
|---|---|---|---|
| MMA | 4‑Hydroxy‑TEMPO (UV‑701) | 48 min | 11.2 |
| MMA | 4‑Butoxy‑TEMPO (UV‑710B) | 65 min | 6.8 |
| Styrene | 4‑Hydroxy‑TEMPO (UV‑701) | 55 min | 9.5 |
| Styrene | 4‑Butoxy‑TEMPO (UV‑710B) | 72 min | 5.4 |
UV‑710B extends inhibition induction period by 30–35% and reduces fouling by 40–45% across both monomer systems.
In high‑temperature aqueous environments (80°C, pH 7–9):
| Property | UV‑710B (4‑Butoxy‑TEMPO) | UV‑701 (4‑Hydroxy‑TEMPO) |
|---|---|---|
| Hydrolysis stability | Ether bond resists hydrolysis | Hydroxyl group forms hydroxylamine (deactivation) |
| Half‑life (t₁/₂) | > 1,000 hours | ~ 120 hours |
UV‑710B maintains activity more than 8× longer in moist, high‑temperature distillation environments.
Fe²⁺ and Cu²⁺ ions from equipment can reduce nitroxide radicals to inactive hydroxylamine:
| Property | UV‑710B | UV‑701 |
|---|---|---|
| Reduction rate constant (k_red) | 80% lower (vs. hydroxyl type) | Baseline |
| Activity retention (8 weeks side‑line circulation) | > 90% | 65% |
The butoxy group provides hydrophobic wrapping and steric hindrance, protecting the nitroxide radical from metal ion attack.
Differential Scanning Calorimetry (DSC, 10 K/min) shows:
| Property | UV‑710B | UV‑701 |
|---|---|---|
| Onset of exothermic decomposition | Safer at 150°C reboiler operation | 180°C |
UV‑710B enables safer operation in bottom reboilers and high‑temperature distillation columns.
UV‑701: High water solubility causes concentration in the top aqueous phase ≈ 3× that of the bottom → insufficient protection of gas/organic phase
UV‑710B: log P = 2.8, water/hydrocarbon partition coefficient ≈ 0.15 → concentration gradient < 20% across the tower → utilization rate > 95%
Industrial comparison in a 6‑meter diameter acrylic acid refining tower:
| Parameter | UV‑710B (25 ppm) | UV‑701 (30 ppm) |
|---|---|---|
| Carbon clearance period | 195 days | 78 days |
UV‑710B extends run length by 2.5×, reducing downtime and maintenance costs.
| Property | UV‑710B | UV‑701 |
|---|---|---|
| Corrosion rate (316L) | < 0.01 mm/a (equivalent to blank) | 0.023 mm/a (pitting from NH₃/HNOₓ decomposition) |
| Tower tray lifespan | 1.5–2× longer | Baseline |
UV‑701 decomposes in high‑temperature aqueous phases to produce trace NH₃ and HNOₓ, causing pitting corrosion. UV‑710B eliminates this risk.
| Property | UV‑710B | UV‑701 |
|---|---|---|
| Storage stability (50 g/L in toluene/isooctane, N₂ seal, dark) | > 12 months activity unchanged | 3–4 months (10% activity loss) |
UV‑710B is ideal for long‑distance transportation and centralized tank farm preparation.
Distillation systems may contain metal ions (Fe³⁺, Cu²⁺) that catalyze unwanted polymerization.
| Property | UV‑710B | UV‑701 |
|---|---|---|
| Metal ion coordination | Oxygen atom wrapped in alkyl chain → weak coordination, minimal impact | Hydroxyl group has coordination ability (some hydroxylamine derivatives can passivate metals) |
UV‑710B is intrinsically less sensitive to metal ion contamination.
Synhipol® UV-710B is highly effective in inhibiting self‑polymerization of:
Typical dosage: 100 – 500 ppm (adjustable per resin reactivity)
| Core Index | UV‑710B (4‑Butoxy‑TEMPO) | UV‑701 (4‑Hydroxy‑TEMPO) |
|---|---|---|
| Inhibition activity | 10–20% higher | Baseline |
| Oil solubility/dispersion | Superior | Moderate |
| Tower concentration gradient | < 20% | ~ 3× top/bottom difference |
| Inhibitor utilization | > 95% | > 75% |
| Hydrolysis stability | > 1,000 h | ~ 120 h |
| Metal ion resistance | 80% lower k_red | Baseline |
| Carbon clearance period | > 6 months | 2–4 months |
| Corrosion | Lower | Higher |
| Storage stability | > 12 months | 3–4 months |
Q1: What is the CAS number of Synhipol® UV-710B?
A: Synhipol® UV-710B (4‑Butoxy‑TEMPO) has CAS number 154186‑23‑9.
Q2: What is the CAS number of 4‑Hydroxy‑TEMPO (UV‑701)?
A: 4‑Hydroxy‑TEMPO has CAS number 2226‑96‑2.
Q3: What monomers does UV‑710B protect?
A: UV‑710B is effective for acrylates, methacrylates, acrylic acid, acrylonitrile, styrene, butadiene, and other polyolefin derivatives during production, separation, refining, and storage.
Q4: What is the typical dosage range for UV‑710B?
A: Typical dosage is 100 – 500 ppm, adjustable based on monomer reactivity and process conditions.
Q5: Why is UV‑710B better than UV‑701 in distillation towers?
A: UV‑701 is water‑soluble, concentrating in the aqueous top phase and leaving the organic/gas phase under‑protected. UV‑710B is oil‑soluble, maintaining uniform distribution (gradient < 20%) and utilization > 95%.
Q6: Does UV‑710B cause corrosion?
A: No. UV‑710B corrosion rate is < 0.01 mm/a, equivalent to blank (no inhibitor). UV‑701 decomposes to NH₃ and HNOₓ, causing pitting corrosion at 0.023 mm/a.
Q7: What is the shelf life of UV‑710B?
A: > 12 months activity unchanged when stored as 50 g/L solution in toluene or isooctane under nitrogen seal, away from light.
Q8: Is UV‑710B suitable for UV‑curable systems?
A: Yes. UV‑710B effectively inhibits premature polymerization in UV ink production lines and acrylate monomer storage before photocuring.
Q9: Can UV‑710B replace UV‑701 directly?
A: Yes. Synhipol® UV-710B is a direct upgrade replacement for 4‑Hydroxy‑TEMPO (UV‑701), offering superior performance with minimal process adjustment.
Q10: How does UV‑710B compare to phenolic inhibitors?
A: UV‑710B's regenerative radical trapping mechanism provides 8× longer inhibition than conventional phenolic antioxidants.
Sinocure Chemical Group
No. 61, South Industrial Road, Jinan Area of Shandong Pilot Free Trade Zone, China
Email: Info@sinocurechem.com | Tel: +86 15668330235
Website: www.sinocurechem.com
For samples, technical data sheets, or process optimization support, please contact our technical team.
This document is for informational purposes only. Users should conduct their own testing to determine suitability for their specific applications. Synhipol® is a registered trademark of Sinocure Chemical Group.
