Abstract: The invention relates to a process for preparing N-alkyl(meth)acrylamides by reacting (meth)acrylic anhydride with corresponding alkylamines.

Abstract: The present invention provides a method for extractive recovery and conversion of selected compounds, such as methacrylic acid (MAA) and 2-methacrylamide (MAM), from a stream derived from purification of methyl methacrylate (MMA) or methacrylic acid (MAA) produced via a conventional ACH route process.

Abstract: The present invention relates to a method for producing N-methyl-N-vinylacetamide, which comprises a step for controlling the N-1,3-butadienyl-N-methylacetamide content in N-methyl-N-vinylacetamide to 0.01-150 ppm. This method enables production of N-methyl-N-vinylacetamide having a stable quality, which can be controlled in stability and polymerizability as a monomer. N-methyl-N-vinylacetamide produced by the method enables production of an N-methyl-N-vinylacetamide polymer having stable physical properties such as a molecular weight.

Abstract: A method of controlling or arresting the rate of depolymerization of a polymer composition during a biocide treatment by controlling the pH of the composition, and use of such methods in oilfield applications.

Abstract: A distillation process for separating a target component from a mixture containing a solvent and the target includes the steps of flashing off a vapor mixture of said solvent and said target in an evaporator, separating said target from said vapor mixture, and providing additional solvent to said evaporator to maintain the temperature of said evaporator substantially below the boiling point of said target. The process also includes the step of removing accumulated non-volatile components from said evaporator by allowing the non-volatile components to precipitate from a mixture of the target and the solvent.

Abstract: Disclosed is a process for producing high-purity N-vinylcarboxamides comprising: (A) a step of dissolving a crude N-vinylcarboxamide in an alcohol having 1 to 3 carbon atoms, the crude N-vinylcarboxamide containing 50 to 97% by mass of an N-vinylcarboxamide; (B) a step of adding an aliphatic hydrocarbon having 5 to 10 carbon atoms to the composition obtained in the step (A) to precipitate a crystal of the N-vinylcarboxamide; and (C) a step of separating the crystal of the N-vinylcarboxamide precipitated in the step (B).

Abstract: The method of separating reversibly thermally precipitable oligomeric N-substituted (meth)acrylamides and conjugates thereof from aqueous solution includes thermally precipitating the oligomeric N-substituted (meth)acrylamides and the conjugates thereof from an aqueous solution in the presence of at least one salt and then filtering in the presence of at least one filter aid. The filter aid has a wet density of 0.2–0.3 g/cc and comprises?99% cellulose with fiber lengths<75 ?m (99%) and=?m (65%). The salt can be a potassium, sodium, ammonium, calcium and/or magnesium chloride, acetate and/or sulfate salt and can be present in the aqueous solution in a concentration between 0.01 M and 3 M.

Abstract: An amide composition containing an unsaturated amide, a sulfur-containing compound, and a weak acid salt. The composition can include an amide in crystalline form or the composition can be in form of aqueous solution. The composition can exhibit improved stability whereby polymerization of the amide is inhibited.

Abstract: In the operation of producing an alkylamino(meth)acrylate by the reaction of transesterification of an alkyl(meth)acrylate with an alkylamino alcohol, the alkyl alcohol by-produced during the transesterification is distilled in the form of an azeotropic mixture with the alkyl(meth)acrylate, the resultant distillate is purified with an ion-exchange resin and handled, on the other hand, the reaction solution is distilled to allow separation of the catalyst wherein is provided a method and apparatus for effecting, in the production of the alkylamino(meth)acrylate, the distillation under such a condition as represses the amount of in crease of the Michael adduct below 2%.

Abstract: A process for preparing acrylic or methacrylic acid amides functionalized with a cationizable tertiary amine, by aminolysis of acrylic or methacrylic acid esters with the aid of enzymes.

Abstract: A purification process of N-vinylformamide, which comprises: providing a crude N-vinylformamide having an acetone-insoluble component content of not more than 400 ppm; and continuously feeding the crude N-vinylformamide into a fractionating tower, to obtain an N-vinylformamide having high purity. Also disclose is a continuous purification process of N-vinylformamide, which comprises the steps of: providing a crude N-vinylformamide; feeding the crude N-vinylformamide into a thin film evaporator to remove un-evaporated fraction from the system, and feeding the evaporated fraction containing N-vinylformamide into a fractionating tower, distilling the purified N-vinylformamide from the tower head, and discharging a bottom liquid containing N-vinylformamide from the tower bottom, and recycling the bottom liquid into the thin film evaporator to remove un-evaporated fraction from the system, and feeding the evaporated fraction into the fractionating tower.

Abstract: The invention provides a method for industrial purification of Capsaicin in high purity from capsinoids (Capsaicin and analogues), more specifically, a method for industrial purification of Capsaicin which comprises contacting capsinoids containing Capsaicin in a hydrophilic solvent with a silver compound in an aqueous solution to form a Capsaicin-silver complex which is soluble in water, and recovering highly pure Capsaicin from the Capsaicin-silver complex without chromatography.

Abstract: A method is disclosed for the concentration of an aqueous acrylamide solution prepared by hydration of acrylonitrile or an aqueous acrylamide solution substantially free of acrylonitrile. The method makes use of a concentration apparatus at least a part of whose solution-contacting section is made of a copper-containing material. The concentration is conducted while introducing an oxygen-containing gas into the apparatus. Use of this method can prevent formation, adhering, accumulation and the like of popcorn polymers inside the concentration apparatus upon concentration of the aqueous acrylamide solution, and can also produce high-quality acrylamide.

Abstract: Disclosed herein is a method of improving the stability of N-vinylamides. A quinone or alkali-modified quinone is added to the N-vinylamide. The loss of the N-vinylamide due to polymerization and/or decomposition during distillation is significantly reduced.

Abstract: This invention provides a process for the preparation of acrylamide. Acrylonitrile is treated through at least two purification steps in which acrylonitrile is brought into contact with a strongly-acidic cation exchange resin and then with a resin having primary and/or secondary amino groups or with activated carbon. The resulting acrylonitrile is subjected to hydration in the presence of a copper-base catalyst. The process of this invention can provide high-quality acrylamide even when acrylonitrile of ordinary quality is used, and permits preparation of a polyacrylamide suitable for use in the production of a coagulant having good water solubility or the like.

Abstract: This invention is directed to producing highly concentrated solutions of methylenebisacrylamide and thereafter blending with ionogenous acrylic monomers to produce low porosity, highly crosslinked, water insoluble polymers.

Abstract: A process for the stabilization of an aqueous acrylamide solution is described which includes adding at least one compound selected from water-soluble monocarboxylic acid salts having at least two carbon atoms to an aqueous solution of acrylamide in an amount of from 20 to 5,000 ppm as acid per acrylamide. According to the present invention, a high purity aqueous acrylamide solution which is markedly stable, even under an iron surface-contacting condition, without causing problems such as the polymerization of acrylamide can be provided by adding a water-soluble monocarboxylic acid salt having at least two carbon atoms.

Abstract: A purification process of crude methacrylamide by recrystallization from an aqueous methacrylamide solution, comprising the steps of conducting crystallization by adjusting the hydrogen ion concentration of the aqueous methacrylamide solution to pH 8 or more, separating a methacrylamide crystal, adjusting 5% by weight or more of resulting mother liquor to pH 5 or less, separating precipitated insoluble matter, and reusing thus-treated mother liquor, is provided.The high quality methacrylamide crystal thus obtained is excellent in Hazen number, purity and transparency of a methanol solution and suitable for uses such as windshield glasses.

Abstract: The present invention relates to a process for the preparation of an N-dialkylaminoalkyl(meth)acrylamide of formula: ##STR1## in which: R.sub.1 is a methyl radical or a hydrogen atom,R.sub.2 is a straight-chain or branched alkyl group containing at most 10 carbon atomsR.sub.3 and R.sub.4, which are identical or different, may be:either two aliphatic alkyl groups containing from 1 to 4 carbon atoms,or R.sub.3 is an aliphatic alkyl group containing from 1 to 4 carbon atoms and R.sub.4 is an alicyclic group containing from 5 to 6 carbon atoms,or R.sub.3 and R.sub.4 are two alicyclic groups containing from 5 to 6 carbon atoms,or R.sub.3 and R.sub.4 form, together with the nitrogen atom to which they are chemically linked, a heterocycloaliphatic group.This process is characterized in that a (meth)acrylic anhydride of formula: ##STR2## is reacted with a diamine of formula: ##STR3## in the presence of a polymerization inhibitor.

Abstract: A method for purifying an aqueous acrylamide solution by using activated carbon is disclosed. The method comprises contacting activated carbon with water having oxygen dissolved therein until the dissolved oxygen concentration in water after the contact increases to at least 0.5 ppm, and then contacting the aqueous acrylamide solution with the thus treated activated carbon. The method can prevent polymerization of acrylamide around activated carbon, and the resulting purified aqueous acrylamide solution requires no further purification, such as ion-exchanging.

Abstract: Acrylamide crystals are prepared from an aqueous solution of acrylamide by causing the aqueous solution and a coolant to flow inside each electrolytically-polished cooling tube of a double-walled or shell-and-tube heat exchanger and outside the cooling tube, respectively, instead of relying upon vacuum crystallization.

Abstract: Trace impurities such as allyl methacrylate and methacrylic acid are removed by contacting methacrylamidopropyltrimethylammonium chloride with a hydrophobic/organophilic microporous crystalline silica.

Abstract: A method comprising contacting a vapor stream resulting from air sparging of aqueous acrylamide containing acrylonitrile with sufficient activated carbon adsorbent to substantially remove acrylamide and acrylonitrile from the vapor stream. This is a particularly advantageous method when aqueous acrylamide is stored in remote locations.

Abstract: Methacrylamidopropyl trimethylammonium chloride and similar quaternized aminoalkyl esters or aminoalkylamides of acrylic acid or methacrylic acid are purified by extraction of an aqueous solution thereof with dichloromethane to remove impurities, such as allyl methacrylamide, which may be formed by a Hofmann degradation of the compounds.

Abstract: In a conventional process for the purification of crude methacrylamide by the recrystallization from an aqueous medium, pH of the aqueous methacrylamide solution is controlled to a value in alkaline range of at least 8 and then methacrylamide is crystallized out. As the alkali used for the pH control, there have been used alkali metal and alkaline earth metal carbonates and hydroxides. Methacrylamide to be recrystallized is crude methacrylamide obtained by neutralizing methacrylamide sulfate obtained from acetone cyanhydrin and sulfuric acid with ammonia in the presence of water.

Abstract: Methacrylamidopropyltrimethylammonium chloride or its free amine, dimethylaminopropylmethacrylamide, is purified by contacting aqueous solutions of the salt or the free amine with solid, nonionic organic resins. Such resins absorb the organic impurities, yet leave behind the polymerization inhibitor.

Abstract: A process is disclosed whereby acrylonitrile and diacetone alcohol are reacted in at least 93% sulfuric acid to form a novel intermediate reaction product which is recovered as a crystalline solid, washed with an organic solvent to remove colored oily impurities along with sulfuric acid, and hydrolyzed to produce diacetone acrylamide, a reactive monomer useful for preparing polymeric components of photographic films and adhesives. The intermediate reaction product is identified as 5,6-dihydro-6-hydroxy-4,4,6-trimethyl-2-vinyl-1,3(4H)-oxazine sulfate (1:1).

Abstract: An aqueous solution of acrylamide obtained by catalytic hydration of acrylonitrile in the presence of a copper-based catalyst is purified by the steps, in sequence, of (a) removal of the unreacted acrylonitrile, (b) removal of copper, (c) treatment under basic conditions, (d) cation exchanging treatment and (e) weakly basic anion exchanging treatment. The acrylamide obtained by this process has good storage stability. An acrylamide polymer produced from this monomer is useful as a flocculant having a reduced content of the unreacted monomer, a high molecular weight and excellent solubility in water.

Abstract: A process for purifying an aqueous acrylamide solution which has been obtained through catalytic hydration of acrylonitrile in the presence of a copper-containing catalyst, by the steps of passing said solution through a OH-form strongly basic anion exchange resin layer and then, through a H-form cation exchange resin layer, is disclosed.

Abstract: A process for purifying an aqueous acrylamide solution which has been obtained by catalytic hydration of acrylonitrile with water in the presence of a copper-containing catalyst is disclosed, said process comprising passing said solution through a weakly basic anion exchange resin having primary and/or secondary amino groups, said resin being replaced with a new one after the use without regeneration.