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Phthalic Anhydride Catalysts

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.

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Why BASF?

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
BASF Catalysts | O4-66 Catalyst

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
BASF Catalysts | O4-88 Catalyst

O4-88 Catalyst Advantage

  • Higher yield vs. O4-66
  • 3 selective layers
  • Patented new active mass
  • Easy start-up behavior
BASF Catalysts | O4-888 Catalyst

O4-888 Catalyst Advantage

  • 5 layer catalyst system
  • Improved selective layers and active layers
  • Excellent product quality

BASF naphthalene/mixed feed PA catalyst

BASF Catalysts | O4-29HFI Catalyst

O4-29HFI Catalyst Advantage

  • Improved 4 layer catalyst generation
  • Higher yield vs. O4-29HF
  • Up to 65% o-Xylene in feed
BASF Catalysts | Close-up of Manufacturing Site
BASF Catalysts | O4-35 Catalysts

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.

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O4-66

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.

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O4-88

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.

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Where We Operate

Click on the map to see the locations of BASF’s research, sales and supply efforts in phthalic anhydride.

News & Media

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BASF O4 35 datasheet

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.

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Industries: Phthalic Anhydride Catalysts

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BASF O4 66 datasheet

O4-66 (7x4x4 mm) was specially designed for the oxidation of o-xylene (o-x) to phthalic anhydride (PA) in a 21-mm tube diameter PA reactor. 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.

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Language: english

Industries: Phthalic Anhydride Catalysts

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BASF O4 68 datasheet

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.

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Language: english

Industries: Phthalic Anhydride Catalysts

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BASF O4 88 datasheet

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.

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Industries: Phthalic Anhydride Catalysts

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BASF O4-888 Datasheet

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.

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Industries: Phthalic Anhydride Catalysts

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