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BASF provides phthalic anhydride (PA) catalysts for the production of phthalic anhydride from the oxidation of o-Xylene and naphthalene or mixed feed. Our products and services are continually reviewed through regular BASF PA Catalyst Customer Forum meetings to ensure they align with our customers’ needs. We innovate to help customers succeed.
For PA producers, BASF's o-Xylene catalysts offer safe operation at a maximum capacity of up to 100 g/Nm3 feed. Our naphthalene and mixed feed catalysts offer superior PA yield. In both cases, superior PA quality is guaranteed by expert technical service and a long-term commitment to innovation, which we demonstrate in our reference list – the longest in the world – and our in-house operations.
BASF has produced phthalic anhydride for over 140 years and researched PA catalysts for more than 120 years. Since 1837, our site in Ludwigshafen, Germany has produced more than 4 million tons of PA. We have worked with post reactors since 1980, and we have more than 80 years of experience in the loading and start-up supervision of phthalic anhydride catalysts. With those decades of accumulated knowledge and insight, we stand behind our products.
When it comes to BASF’s offerings, delivering products to the customer site is just the beginning. Our technical service representatives in Asia, Europe and America ensure products always perform and deliver exceptional value to users. They do that with extensive professional expertise in phthalic anhydride catalysts, including hands-on operational experience in supervision, start-up assistance, and catalyst performance optimization.
Our expertise includes:
O-Xylene and naphthalene/mixed feed oxidation in fixed bed process
O-Xylene loadings up to 100 g/Nm3
Supply of complete catalyst filling and measurement equipment on loan basis, including 5-tube, 10-tube and 20-tube catalyst filling machines
Optimization of catalyst operation condition using portable COx analyzers
Verification of air flow measurements by total combustion
Technologies
Whether you work with o-Xylene feed or naphthalene/mixed feed phthalic anhydride catalysts, BASF products provide a wide range of benefits such as higher yield, improved selective and active layers, better stability, and overall exceptional quality and performance.
BASF o-x feed PA catalyst
O4-68 Catalyst Advantage
Higher proportion of selective layers per tube
Hot Spot (HS) remains longer in selective layers
Higher Phthalic Anhydride yield in 2nd operation year
Top performance for low loading
O4-66 Catalyst Advantage
Improved 4-layer catalyst generation
Improved stability of 1st
catalyst layer
Designed for harsh operation conditions
Higher Phthalic Anhydride yield in 2nd and 3rd operation year
O4-88 Catalyst Advantage
Higher yield vs. O4-66
3 selective layers
Patented new active mass
Easy start-up behavior
O4-888 Catalyst Advantage
5 layer catalyst system
Improved selective layers and active layers
Excellent product quality
BASF naphthalene/mixed feed PA catalyst
O4-29HFI Catalyst Advantage
Improved 4 layer catalyst generation
Higher yield vs. O4-29HF
Up to 65% o-Xylene in feed
O4-35 Catalyst Advantage
Latest generation 5-layer catalyst system
Catalyst geometry adjusted for maximum performance
Superior PA quality
Product Portfolio
Browse our PA catalysts to learn more about the benefits of a particular product.
Phthalic Anhydride Catalysts Brochure
BASF offers over 135 years experience in Phthalic Anhydride (PA) production and 110 years in catalyst research. This legacy forms a strong foundation for continuous innovation and product improvement.
O4-68
O4-68 is designed for the oxidation of o-xylene (o-x) to phthalic anhydride (PA) at medium o-x loading.
Its outstanding features include high stability and excellent selectivity. O4-68 is a robust and durable catalyst, its improved 4-layer catalyst system guarantees safe operation, long catalyst lifetime and stable PA yield at harsh operation conditions with an exceptionally low salt bath temperature (SBT) increase rate. The formation of by-products, such as phthalide, is very low, which ensures good PA quality.
O4-66 is designed for the oxidation of o-xylene (o-x) to phthalic anhydride (PA) with up to 100 g/Nm3 o-x loading and 4.0 Nm3/hr/tube air flow rate.
Its outstanding features include high stability and excellent selectivity. O4-66 is a robust and durable catalyst, its improved 4-layer catalyst system guarantees safe operation, long catalyst lifetime and stable PA yield at harsh operation conditions with an exceptionally low salt bath temperature (SBT) increase rate. The formation of by-products, such as phthalide, is very low, which ensures good PA quality. O4-66 can be combined with a PA post reactor.
O4-88 is designed for the oxidation of o-xylene (o-x) to phthalic anhydride (PA) with up to 100 g/Nm3 o-x loading and 4.0 Nm3/hr/tube air flow rate.
Its outstanding features include high stability and excellent selectivity. Like its proven predecessor, O4-66, the new 5-layer O4-88 is a robust, durable and safe catalyst. The fully activated, high C8-selectivity CL0 layer selectively converts o-x to more intermediates. O4-88’s patented CL0 layer and improved CL3 layer ensure higher PA yield and longer catalyst lifetime. O4-88 can be combined with a PA post reactor.
O4-35 was designed for the oxidation of naphthalene (naph) or a mixture of naph and o-xylene (o-x) to phthalic anhydride (PA). The latest generation 5-layer O4-35 consists of 3 selective layers (CL1-CL3) and 2 active layers (CL4-CL5). The additional selective layer allows naph loading up to 90 g/Nm3. The CL4 and CL5 layer are adjusted to achieve maximum performance and a superior PA quality.
O4-66 was designed for the oxidation of o-xylene (o-x) to phthalic anhydride (PA) at up to 100 g/Nm3 o-x loading and 4.0 Nm3/hr/tube air flow rate. Its outstanding features include high stability and excellent selectivity. O4-66 is a robust and durable catalyst, its improved 4-layer catalyst system guarantees safe operation, long catalyst lifetime and stable PA yield at harsh operation conditions with an exceptionally low salt bath temperature (SBT) increase rate. The formation of by-products, such as phthalide, is very low, which ensures good PA quality. O4- 66 can be combined with a PA post reactor.
O4-68 was designed for the oxidation of o-xylene (o-x) to phthalic anhydride (PA) at medium o-x loading. Its outstanding features include high stability and excellent selectivity. O4-68 is a robust and durable catalyst, its improved 4-layer catalyst system guarantees safe operation, long catalyst lifetime and stable PA yield at harsh operation conditions with an exceptionally low salt bath temperature (SBT) increase rate. The formation of by-products, such as phthalide, is very low, which ensures good PA quality.
O4-88 was designed for the oxidation of o-xylene (o-x) to phthalic anhydride (PA) at up to 100 g/Nm3 o-x loading and 4.0 Nm3/hr/tube air flow rate. Its outstanding features include high stability and excellent selectivity. Like its proven predecessor, O4-66, the new 5-layer O4-88 is a robust, durable and safe catalyst. The fully activated, high C8-selectivity CL0 layer selectively converts o-x to more intermediates. O4-88’s patented CL0 layer and improved CL3 layer ensure higher PA yield and longer catalyst lifetime. O4-88 can be combined with a PA post reactor.
O4-888 was designed for the oxidation of o-xylene (o-x) to phthalic anhydride (PA) at up to 100 g/Nm3 o-x loading and 4.0 Nm3/hr/tube air flow rate. Its outstanding features include high stability and excellent selectivity. The 5-layer O4-888 combines the advantages of good PA quality from O4-66 and high PA yield from O4-88. The optimized CL4 layer exhibits a higher activity towards selective C8 intermediates conversion, thus ensuring safe operation with superior PA quality. O4-888 can be combined with a PA post reactor.
