The Dow Chemical Company

Dow Global Technolgoies LLC

Dow Technology Investments LLC

Sten A Wallin

Arthur Richard Prunier, Jr

Aleksander Jozef Pyzik

Sunil D Wijeyesekera

Chandan Saha

Kevin E Howard

Todd R Bryden

Peter C Lebaron

Robert Thomas Nilsson

Chan Han

Robin Paul Ziebarth

Fredrick W Vance

Timothy J Gallagher

David H West

Christopher P Christenson

Madan Mohan Bhasin

Sharon Allen

John R Moyer

Clifford S Todd

Duane K Wolcott

Stephen A Noding

Martin C Cornell

Juliana G Serafin

Steven R Lakso

Henri J M Gruenbauer

Timothy L Allen

Carolyn W Ribes

Beatriz Cisneros

Zoran R Jovanovic

Charles B Miller

Arthur M Prunier

Jamie L Lovelace

Arthur R Prunier

Chandan K Saha

The present invention provides porous body precursors and shaped porous bodies. Also included are catalysts and other end-use products based upon the shaped porous bodies and thus the porous body precursors. Finally, processes for making these are provided. The porous body precursors comprise a precursor alumina blend capable of enhancing one or more properties of a shaped porous body based thereupon. The need to employ modifiers to achieve a similar result may thus be substantially reduced, or even avoided, and cost savings are thus provided, as well as savings in time and equipment costs.

Porous body precursors, shaped porous bodies, processes for making them, and end-use products based upon the same

The present invention provides porous body precursors and shaped porous bodies. Also included are catalysts and other end-use products based upon the shaped porous bodies and thus the porous body precursors. Finally, processes for making these are provided. The porous body precursors, comprise one or more topography-enhancing additives, i.e., additives that are capable of at least marginally enhancing one or more of surface area, aspect ratio, pore volume, median pore diameter, surface morphology, etc. Downstream products need not necessarily comprise the topography-enhancing additives in order to exhibit the benefits of their inclusion in the porous body precursors.

A method of forming a porous mullite composition of acicular mullite grains having improved properties is described, where the mullite is formed at some time in the presence of a fluorine containing gas. For example, it has been discovered that improved properties may result from heating the mullite to a high temperature in an atmosphere selected from the group consisting of water vapor, oxygen, an inert gas or mixtures thereof or forming the mullite composition from precursors having an Al/Si ratio of at most 2.95.

Mullite bodies and methods of forming mullite bodies

A porous mullite composition is made by Forming a mixture of one or more precursor compounds having the elements present in mullite (e.g., clay, alumina, silica) and a property enhancing compound. The property enhancing compound is a compound having an element selected from the group consisting of Mg, Ca, Fe, Na, K, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb, Lu, B, Y, Sc, La and combination thereof. The mixture is shaped and to form a porous green shape which is heated under an atmosphere having a fluorine containing gas to a temperature sufficient to form a mullite composition comprised substantially of acicular mullite grains that are essentially chemically bound.

Porous mullite bodies and methods of forming them

A porous mullite composition is made by forming a mixture of one or more precursor compounds having the elements present in mullite (e.g., clay, alumina, silica) and a property enhancing compound. The property enhancing compound is a compound having an element selected from the group consisting of Mg, Ca, Fe, Na, K, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, B, Y, Sc, La and combination thereof. The mixture is shaped and to form a porous green shape which is heated under an atmosphere having a fluorine containing gas to a temperature sufficient to form a mullite composition comprised substantially of acicular mullite grains that are essentially chemically bound.

A method of forming a porous mullite composition of acicular mullite grains having improved properties is described, where the mullite is formed at some time in the presence of a fluorine containing gas. For example, it has been discovered that improved properties may result from heating the mullite to a high temperature in an atmosphere selected from the group consisting of water vapor, oxygen, an inert gas or mixtures thereof or forming the mullite composition from precursors having an AL/Si ratio of at most 2.95.

Method of forming mullite bodies

The invention is a catalytic device comprised of a catalyst support of fused ceramic grains and a catalyst that is surface-bound to at least a portion of the ceramic grains, incorporated into at least a portion of the ceramic grains or combinations thereof, wherein the grains and catalyst form a surface structure that has a box counting dimension of greater than 1.00 or the box counting dimension has at least one step change when measured from a box size 'd' of at least about 1 micrometer to at most about 1 millimeter. The invention is particularly useful in making a catalytic converter or catalytic converter-soot trap.

Catalytic devices and method of making said devices

A ceramic honeycomb wall-flow filter is prepared by plugging channels in a clay containing ceramic honeycomb by a method that has the following steps. First, a mixture of a dispersing liquid and ceramic powder is formed. Second, the mixture is inserted into at least one channel of a clay containing green ceramic honeycomb to form a plugged green ceramic honeycomb wherein the dispersing liquid essentially fails to swell the clay. Alternatively, the mixture is inserted into a calcined ceramic honeycomb to form a plugged calcined ceramic honeycomb. Finally, the plugged green or calcined ceramic honeycomb is heated to a temperature sufficient to sinter the plugged green ceramic honeycomb to form a porous sintered plugged ceramic honeycomb. The method is particularly useful for simultaneously making the plugs and discriminating layers in the channels. In particular the method is useful to make wall-flow filters having plugs on at least one end with same composition as the discriminating layer or plugs on each end having different compositions.

Method of making wall-flow monolith filter

A ceramic honeycomb wall-flow filter is prepared by plugging channels in a ceramic honeycomb by a method comprising the following. First, a mixture comprised of a dispersing liquid and ceramic powder is formed. Next, the mixture is inserted on one end of the channel in an unplugged ceramic honeycomb such that the mixture flows to the other end where the mixture collects and forms a plugged ceramic honeycomb. Then, the plugged ceramic honeycomb is heated to a temperature sufficient to sinter the plugged ceramic honeycomb to form a porous sintered plugged ceramic honeycomb.

A mullite composition is comprised substantially of mullite grains that are essentially chemically bound wherein the composition has at least two adjoining regions that have substantially different microstructures. The composition may be produced by forming a mixture of one or more precursor compounds having the elements present in mullite; shaping the mixture into a porous green shape applying a nucleation control agent to a portion of the porous green shape and then heating the porous green shape under an atmosphere and to a temperature sufficient to form the mullite composition.

A high performance electrocatalyst is based on transition metal perovskites of praseodymium, samarium, terbium or neodymium which react with YSZ to form a product which is itself active as the cathode in a fuel cell. While PrCoO reacts with YSZ, the reaction product(s) do not result in severe degradation of cell performance. A fuel cell made with a cathode composed of only the reaction product of YSZ and PrCoO has good performance, indicating that this phase is itself not only a good conductor, but also a good catalyst for oxygen activation.

Cathode composition for solid oxide fuel cell

A high performance electrocatalyst is based on transition metal perovskites of praseodymium, samarium, terbium or neodymium which react with YSZ to form a product which is itself active as the cathode in a fuel cell. While PrCoO,reacts with YSZ, the reaction product(s) do not result in severe degradation of cell performance. A fuel cell made with a cathode composed of only the reaction product of YSZ and PrCoO,has good performance, indicating that this phase is itself not only a good conductor, but also a good catalyst for oxygen activation.

A high performance electrocatalyst is based on transition metal perovskites of praseodymium, samarium, terbium or neodymium which react with YSZ to form a product which is itself active as the cathode in a fuel cell. While PrCoO.sub.3 reacts with YSZ, the reaction product(s) do not result in severe degradation of cell performance. A fuel cell made with a cathode composed of only the reaction product of YSZ and PrCoO.sub.3 has good performance, indicating that this phase is itself not only a good conductor, but also a good catalyst for oxygen activation.

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Midland, MI, United States of America

Sten A Wallin