Provided is an alumina-based composite oxide having a large initial specific surface area and a small initial mean pore size, with excellent heat resistance of the specific surface area and pore volume; and a production method therefor. Specifically, provided is an alumina-based composite oxide wherein the initial crystallite diameter is 10 nm or less and the initial specific surface area is 80 m.sup.2/ml or more; after calcination at 1200° C. for 3 hours in air, the specific surface area is 10 m.sup.2/ml or more; the initial mean pore size is 10 nm or more and 50 nm or less; and after calcination at 1200° C. for 3 hours in air, the pore volume retention rate is 10% or more, which is determined by (P.sub.1/P.sub.0)×100 wherein P.sub.0 represents an initial pore volume (ml/g), and P.sub.1 represents a pore volume (ml/g) after calcination at 1200° C. for 3 hours in air.

The present invention provides highly dispersible precipitated silica having improved structure and properties for use as reinforcing filler in elastomeric compositions and method of preparation thereof. The present invention further provides an alkaline silicate solution having reduced dielectric constant by digesting biogenic silica source with alkaline solution such that soluble organic compounds present in the biogenic silica source leach into the alkaline silicate solution. The alkaline silicate solution obtained as above is then acidified with a mineral acid under particular conditions of pH, temperature, time etc. to obtain the highly dispersible precipitated silica of the present invention.

The invention relates to a novel method of preparing silicas and to highly-structured silicas having the following characteristics: a specific surface area CTAB (S.sub.CTAB) of between 40 and 525 m.sup.2/g; a specific surface area BET (S.sub.BET) of between 45 and 550 m.sup.2/g; an object size distribution width Ld ((d84−D16)/d50), which is measured by XDC particle size analysis after deagglomeration with ultrasound, of at least 0.91; and a pore-size distribution such that ratio V(d5−d50)/V(d5−d100) is at least 0.66. The invention also relates to the use of said silicas as polymer reinforcing fillers.

Silica particles have silica base particles, a structure that covers at least a part of a surface of the silica base particles and is configured with a reaction product of a trifunctional silane coupling agent, and a nitrogen element-containing compound, in which a content of the nitrogen element-containing compound with respect to the silica particles is 0.005% by mass or more and 0.50% by mass or less in terms of N atoms, and the silica particles have a degree of hydrophobicity of 10% or more and 60% or less and a volume resistivity of 1×10.sup.8Ω.Math.cm or more and 1×10.sup.12.5 Ω.Math.cm or less.

A solid composition contains a first material and a powder and satisfies requirements 1 and 2. Requirement 1: |dA(T)/dT| satisfies 10 ppm/° C. or more at least at −200° C. to 1,200° C. A is (an a-axis lattice constant of a crystal in the powder)/(a c-axis lattice constant of a crystal in the powder), obtained from X-ray diffractometry of the powder. Requirement 2: C is 0.04 or more. C is (a log differential pore volume when a pore diameter of the solid composition is B in a pore distribution curve of the solid composition)/(a log differential pore volume corresponding to a maximum peak intensity in the pore distribution curve of the solid composition). B is (a pore diameter giving a maximum peak intensity in the pore distribution curve of the solid composition)/2. The pore distribution curve of the solid composition shows a relationship between the pore diameter and the log differential pore volume.

To provide low CTE and low puffing needle coke more stably while dealing with changes in the properties of a feedstock. The low CTE and low puffing needle coke is obtained by mixing and coking a needle coke main feedstock of a coal tar-based heavy oil or petroleum-based heavy oil having a weak hydrogen donating property with a PDQI value expressed by equation (1) of less than 5.0, with a secondary feedstock having a strong hydrogen donating property with a PDQI value expressed by equation (1) of 5.0 or more, and calcining the obtained raw coke. [Equation (1)] PDQI=H %×10×(HNβ/H), wherein H % is a hydrogen amount (% by weight) obtained by elemental analysis, and HNβ/H is a ratio of β naphthenic hydrogen to total hydrogen measured by .sup.1H-NMR.

The invention relates to a zeolitic material comprising zeolitic monocrystals, each of which has a pore system encompassing at least one micropore system and at least one macropore system, and to a method for producing a zeolitic material of said type. In said method, porous oxide particles are converted into the zeolitic material in the presence of an organic template and steam.

A carbon dioxide adsorbent including silica gel and an amine compound carried by the silica gel. The silica gel has a spherical shape, a particle size ranging from 1 mm to 5 mm inclusive, an average pore diameter ranging from 10 nm to 100 nm inclusive, a pore volume ranging from 0.1 cm.sup.3/g to 1.3 cm.sup.3/g inclusive, and a waterproof property N that is defined by an expression (1) and that is not lower than 45%,

N=(W/W.sub.0)×100  (1) where N is the waterproof property in percentage (%) of the silica gel, W.sub.0 is a total number of particles of the silica gel immersed in water, W is a number of particles of the silica gel not subjected to breakage out of W.sub.0.

The present invention pertains to a hydrous silica for rubber-reinforcing filler, having a BET specific surface area ranging from 230 to 350 m.sup.2/g, and satisfies the following: a) the pore volume of 1.9 nm to 100 nm pore radius measured by the mercury press-in method (V.sub.HP-Hg) ranges from 1.40 to 2.00 cm.sup.3/g; b) total pore volume in the range of 1.6 nm to 100 nm pore radius by the nitrogen adsorption/desorption method (V.sub.N2) ranges from 1.60 to 2.20 cm.sup.3/g; and c) the pore volume ratio of (a) and (b) V.sub.HP-Hg/V.sub.N2 ranges from 0.70 to 0.95. This invention provides a hydrous silica capable of further improving reinforcing properties of a rubber, particularly the wear resistance by improving dispersibility of the hydrous silica in the rubber in addition to rubber reinforcing properties obtained by a high BET specific surface area.

A silica that is superior in terms of fluidity, oil absorption ability, and compression moldability to conventional silica used as a pharmaceutical additive, and is suitable as an additive for formulations such as pharmaceuticals. A porous silica particle composition having the following properties: (1) a BET specific surface area from 250 to 1,000 m.sup.2/g; (2) an average particle diameter from 1 to 150 μm; (3) a pore volume from 0.1 to 8.0 cm.sup.3/g; and (4) an oil absorption capacity from 2.2 to 5.0 mL/g.