| Patent Number |
Title Of Patent |
Date Issued |
| RE39182 |
Process for the preparation of thermally stable polyoxymethylene copolymers |
July 11, 2006 |
| A process for the preparation of polyoxymethylene copolymers, wherein 1,3,5-trioxane is polymerized with generally known comonomers in the presence of a strong protonic acid initiator and in the presence of a formaldehyde dialkyl acetal, and wherein the initiator is dissolved in the |
| 7534922 |
Processes for the manufacture of acetals |
May 19, 2009 |
| A process for preparing acetals from aldehydes and alcohols is carried out by generating a reaction/distillation zone charged with an acidic fixed bed catalyst in a distillation column, feeding the aldehyde and the alcohol to the reaction/distillatlon zone and at least partly converting |
| 7301055 |
Process for removing methanol from formaldehyde-containing solutions |
November 27, 2007 |
| Process for removing methanol from formaldehyde-containing solutions. The present invention relates to a process for removing methanol from formaldehyde-containing solutions, with methanol being converted into formaldehyde dimethyl acetal by reactive distillation in the presence of a |
| 7001959 |
Polyoxymethylene copolymers, their preparation and use |
February 21, 2006 |
| Copolymers are described containing blocks of the structural repeat units of the formula I and blocks containing structural units of the formula II [--O--CH.sub.2--].sub.x, (I) [--O--R.sup.1--], (II) where R.sup.1 is a divalent radical derived from a hydroxy-terminated aliphatic or |
| 6306940 |
Colorant concentrates for dyeing polyoxymethylene moulding materials |
October 23, 2001 |
| Colorant concentrates made from free-flowing polyoxymethylene copolymer as carrier, 15-80% by weight of colorant, 2-15% by weight of nitrogen-containing stabilizer and 0-15% by weight of dispersion aid for coloring pellets or molding compositions made from polyoxymethylene (POM) and |
| 6169164 |
Process for preparing polyoxymethylene molding compositions of improved quality |
January 2, 2001 |
| A process for the cationically initiated preparation of oxymethylene copolymers in which, after the polymerization and after comminution of the crude polymer in a grinding assembly a portion of the deactivation suspension comprising the ground crude polymer is removed downstream of t |
| 5955041 |
Natural circulation reactor and use for producing linear and cyclic acetals |
September 21, 1999 |
| This invention relates to a reactor 1 for the continuous production of linear or cyclic acetals, in particular trioxane, dioxolane, tetroxane, dimethoxymethane, diethoxymethane, diethoxyethane and dibutoxyethane. This reactor has internal adjacently arranged evaporator elements 2, which |
| 5872263 |
Process for separating formaldehyde and trioxane |
February 16, 1999 |
| A process for separating a gaseous reaction mixture in the preparation of trioxane is described, in which a) the gaseous mixture leaving the reactor is scrubbed in countercurrent with an organic solvent whose boiling point is above 135.degree. C. in which the trioxane predominantly disso |
| 5766424 |
Process for removing trioxane from an aqueous mixture |
June 16, 1998 |
| A process for removing trioxane from a liquid mixture containing trioxane, water and formaldehyde, which includes distilling the liquid mixture in a first distillation stage at a low pressure, distilling the resulting distillate in a second distillation stage at a higher pressure and tak |
| 5608030 |
Process for the preparation of polyacetals |
March 4, 1997 |
| Process for continuous preparation of homo- and copolyoxymethylenes with stable end groups in a homogeneous phase, in which in a tubular reactor with static mixing elements cyclic formaldehyde oligomers are polymerized in the presence of protonic acids as initiators in amounts of 0.005 t |
| 5587449 |
Process for the preparation of polyacetal copolymers |
December 24, 1996 |
| In the process for the preparation, with simultaneous end group stabilization, of polyacetal copolymers in a homogeneous phase and working up thereof, cyclic formaldehyde oligomers are copolymerized with cyclic acetals in the presence of an initiator in a polymerization reactor and i |
| 5508449 |
Process for the preparation of trioxane |
April 16, 1996 |
| In a process for the preparation of trioxane from formaldehyde in the gas phase in the presence of a catalyst, the catalyst employed is 11-molybdo-1-vanadophosphoric acid, H.sub.4 PVMo.sub.11 O.sub.40 .multidot.n H.sub.2 O (n=0-32).Advantages of this process are, inter alia, high space-t |
| 5508448 |
Process for the preparation of trioxane |
April 16, 1996 |
| A process for the catalytic preparation of trioxane from formaldehyde in the gas phase employs a catalyst comprising vanadyl hydrogenphosphate hemihydrate which may be unactivated or activated by steam.No byproducts were obtained in the process and the space-time yield is high. Deposits |
| 5144005 |
Continuous process for removing unstable components from crude oxymethylene copolymer |
September 1, 1992 |
| Continuous process for removing unstable components from crude oxymethylene copolymer, which still contains catalysts, monomeric starting materials and unstable components, by treating the copolymer with deactivators, optionally in the presence of auxiliaries, in a pressure zone, and |
| 5102838 |
Catalyst for selective oxidation reactions |
April 7, 1992 |
| Silicate catalysts which can be employed for selective oxidation reactions of organic substances, a process for the preparation of these catalysts and their use are described.The catalyst is distinguished by high long-term activity, by the reaction temperature required for the reaction b |
| 5041686 |
Process for the preparation of carbonyl compounds |
August 20, 1991 |
| A process for the preparation of carbonyl compounds by the oxydehydrogenation of (C.sub.1 -C.sub.4)-alcohols is carried out at a temperature from 400.degree. to 700.degree. C. in the presence of a silicate catalyst which has been doped with silver and silver ions. By means of the pro |
| 5008463 |
Process for the preparation of formaldehyde |
April 16, 1991 |
| The process dehydrogenates methanol in the presence of a catalyst based on aluminum oxide, alkali metal aluminate and/or alkaline earth metal aluminate with the exclusion of oxygen at a temperature of 650.degree. to 1050.degree. C. in a reactor whose inner wall is composed entirely or |
| 4946561 |
Process for obtaining trioxane from aqueous solutions by high-pressure extraction |
August 7, 1990 |
| The invention relates to a process for obtaining trioxane from aqueous solutions by high-pressure extraction using an extracting agent which is in the form either of a gas in the supercritical state or of a liquid gas. An intermediate separation is advantageous, especially in the former |
| 4703129 |
Process for the continuous preparation of trioxane |
October 27, 1987 |
| The invention relates to a process for the continuous preparation of trioxane, optionally together with cyclic formals, from an aqueous formaldehyde solution in the presence of acidic solid-bed catalysts, the reaction taking place without simultaneous evaporation.The process according to |
| 4504670 |
Process for the continuous manufacture of trioxane |
March 12, 1985 |
| The invention provides a process for the continuous manufacture of trioxan, optionally together with cyclic formals, from aqueous formaldehyde solutions in a circulation reactor with evaporator, the vapor/liquid mixture leaving the evaporator is fed in below the liquid level of the r |
| 4353856 |
Process and embedding system for embedding tissue samples |
October 12, 1982 |
| The invention relates to a process and an embedding system for embedding tissue samples in a mixture of a hydroxyalkyl (meth)acrylate and an alkyl (meth)acrylate in a weight ratio of at most 9:1. The embedding process takes place at low temperatures using a low-temperature initiator syst |
| 4340542 |
Process and equipment for the continuous manufacture of trioxan |
July 20, 1982 |
| The invention relates to a process for the continuous manufacture of trioxan, if appropriate together with cyclic formals, from aqueous formaldehyde solutions in a circulation reactor with an evaporator, wherein the vapor/liquid mixture, before it enters the reactor, is separated int |
| 4323502 |
Process for the simultaneous preparation of trioxan and cyclic formals |
April 6, 1982 |
| A process for the simultaneous synthesis of trioxan and cyclic formals is provided, which comprises reacting a mixture of concentrated formaldehyde and diol and/or epoxide with acid catalysts at a temperature of from 30.degree. to 150.degree. C. |
| 4150238 |
Antiviral polymer |
April 17, 1979 |
| Poly(acrylic acid) salts having specific structural characteristics, which salts are useful for combatting virus diseases. |
| 4124751 |
Process for preparing acrylic acid or methacrylic acid ester polymer having a high isotacticity |
November 7, 1978 |
| Esters of acrylic acid and methacrylic acid may be polymerized with the aid of either free radical forming or ionically effective initiators. The stereospecificy of the polymers may be influenced by the selection of specific initiators; magnesium-organic compounds are suitable for the |
| 4111858 |
Process for the preparation of polyhydroxy methylene ethers and ion exchangers composed thereof |
September 5, 1978 |
| This invention relates to an improvement in the process for the preparation of a polyhydroxy methylene ether in which polyhydroxy methylene is reacted with an alkylating agent in an aqueous alkaline medium, the improvement comprising that the alkylating agent has at least one ionic or io |
