E.i. Dupont De Nemours and Company

Thurman E Gier

August Ferretti

George C Sonnichsen

John D Bierlein

Robert D Shannon

David Richard Corbin

Patricia A Morris

Albert A Ballman

Michael Keane, Jr

Novel molecular sieves are disclosed which are oxides of (a) an alkali metal, an alkaline earth metal and/or ammonium, (b) beryllium, cobalt and/or zinc, and (c) phosphorous, arsenic and/or vanadium, and optionally contain water. These zeolite-like materials, which contain little or no aluminum or silicon, can be made by a novel low temperature process. The molecular sieves are useful as ion exchange resins.

Process for producing molecular sieves and novel molecular sieve

A composition is disclosed which consists essentially of doped crystalline MTiOXO.sub.4 (wherein M is selected from the group consisting of K, Rb and Tl, X is selected from the group consisting of P and As) which contain at least about 100 ppm total of at least one dopant selected from the group consisting of Ga, Al and Si. The compositions generally have low ionic conductivity, and may be prepared using an improved flux process wherein Ga, Al and/or Si dopant is added to the flux in a total amount of at least about 0.5 mole % and the crystallization temperature is controlled to provide a crystalline composition containing the desired amount of dopant.

Doped crystalline compositions and a method for preparation thereof

A hydrothermal process for growing a crystal of MTiOXO.sub.4 at an elevated temperature is disclosed which employs a growth medium comprising a mineralizer solution, and is characterized as employing aqeuous mineralizer solution in which the concentration of M is at least about 8 molar, and as employing a growth region temperature of less than about 500.degree. C. and/or a pressure of less than 14,000 psi during crystallization. M is selected from the group consisting of K, Rb, Tl and NH.sub.4 and mixtures thereof, and X is selected from the group consisting of P and As and mixtures thereof.

Hydrothermal process for growing optical-quality single crystals

A process is provided for producing dimethylamine, comprising reacting methanol and/or dimethylether and ammonia, in amounts sufficient to provide a carbon/nitrogen (C/N) ratio of from about 0.2 to about 1.5, at a temperature from about 250.degree. C. to about 450.degree. C., in the presence of a catalytic amount of an acidic zeolite rho.

Zeolite Rho as catalyst for conversion of methanol and ammonia to

A process is provided for producing dimethylamine comprising reacting methanol and/or dimethylether and ammonia in amounts sufficient to provide a carbon/nitrogen (C/N) ratio from about 0.2 to about 1.5, at a temperature from about 250.degree. C. to about 450.degree. C., in the presence of a catalytic amount of an acidic H-ZK-5 zeolite catalyst.

Zeolite H-ZK-5 as catalyst for conversion of methanol and ammonia to

Stable glass whose composition is defined by the quadrilaterals I II III IV of the accompanying ternary diagrams of FIGS. 1 and 2 for the system selected from the group consisting of K.sub.2 O/P.sub.2 O.sub.5 /(TiO.sub.2).sub.2, Rb.sub.2 O/P.sub.2 O.sub.5 /(TiO.sub.2).sub.2, K.sub.2 O/As.sub.2 O.sub.5 /(TiO.sub.2).sub.2 and Rb.sub.2 O/As.sub.2 O.sub.5 /(TiO.sub.2).sub.2 ; and the use of such glass in hydrothermal processes for producing crystals of KTiOPO.sub.4 and certain crystal analogues thereof, namely, RbTiOPO.sub.4, KTiOAsO.sub.4 and RbTiOAsO.sub.4.

Hydrothermal process for growing a single crystal with an aqueous

A process for the manufacture of single crystals of MTiOXO.sub.4, wherein M is K, Rb or Tl and X is P or As, of optical quality and of sufficient size for use in nonlinear optical devices. In the process, starting ingredients chosen to be within the region of the ternary phase diagram in which the desired crystal MTiOXO.sub.4 product is the only stable solid phase, are heated to produce MTiOXO.sub.4 and then controllably cooled to crystallize the desired product. In a preferred method the ingredients are placed in a temperature gradient in which the hot zone ranges from about 800.degree.-1000.degree. C. and the cold zone about 10.degree.-135.degree. C. cooler, maintaining the temperature gradient for about 3 days to about 3 weeks, cooling, and recovering MTiOXO.sub.4 crystals.

Method for flux growth of KTiOPO.sub.4 and its analogues

Crystals of compounds of the type (K, Rb, Tl, NH.sub.4)TiO(P, As)O.sub.4 with the proviso that when NH.sub.4 is present, As is absent, can be grown by hydrothermal methods. The crystals are optically biaxially positive, and piezoelectric and are useful in parametric amplifiers, oscillators, second harmonic generators, modulators and the like.

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Chadds Ford, PA, United States of America

Thurman E Gier