Abstract: A method is described for producing acrylamide from acrylonitrile by the action of a microorganism having nitrilase activity in an aqueous medium, which comprises conducting the reaction in the presence of an alkali metal sulfate at an ionic activity of from 0.004 to 0.01 mole per liter while controlling the pH of said aqueous medium within a range of from 7 to 9 with an alkali hydroxide.

Abstract: A method for purifying a reaction solution obtained by using a microbial cell, an immobilized microbial cell, or an immobilized enzyme as a catalyst in a water medium is disclosed. The method comprises repeatedly filtering the reaction solution to remove fine solid matter using a polyethylene porous hollow fiber membrane having a bubble point of from 1 to 20 kg/cm.sup.2, and repeatedly washing the hollow fiber membrane before it has been clogged to such an extent that a differential pressure thereof exceeds 3 kg/cm.sup.2. By this method, a filter membrane can be repeatedly regenerated at high efficiency and can stably be used for a long period of time.

Abstract: A process for preparing an antimony/tellurium-containing metal oxide catalyst, comprising preparing a slurry containing an antimony compound, a polyvalent metal compound, and a silica support starting material selected from silica sol and mixtures of silica sol and white carbon, fumed silica or silica hydrogel, heating the slurry at a pH or 7 or less and a temperature of at least 40.degree. C., mixing the above heat treated slurry with a tellurium solution which has been independently prepared by oxidizing metallic tellurium with hydrogen peroxide in the presence of the oxide, oxyacid or oxyacid salt of at least one metal selected from the group consisting of vanadium, molybdenum and tungsten, and then drying and calcining the resulting mixture.

Abstract: A process for producing N-substituted maleimides which comprises heating maleic anhydride and an aromatic or aliphatic amine, or maleic acid monoamides obtained from them, in the presence of an ion exchange resin in an organic solvent to effect cyclodehydration.

Abstract: A method of stabilizing an aqueous solution of xanthan gum is disclosed, comprising incorporating at least one stabilizing agent selected from thiol derivatives of heterocyclic compounds in an aqueous solution of xanthan gum.

Abstract: There is disclosed a process for producing 7,7,8,8-tetracyanoquinodimethane, which comprises subjecting 1,4-bis-(dicyanomethylene)-cyclohexane to anodic oxidation in a solvent.

Abstract: A process for producing an inorganic compound-containing urea resin, which comprises adding an acidic gelling agent to an aqueous urea-formaldehyde precondensate solution to prepare a urea resin-containing product, and either(1) mixing the product with a reactant which reacts with the gelling agent to form inorganic particles substantially insoluble in water, or(2) separating the urea resin from the product, mixing the resin-freed mother liquor with such a reactant as stated above, and mixing the resulting inorganic particles with the separated urea resin.

Abstract: The activity of a tellurium-free metal oxide catalyst used for ammoxidation of organic compounds at a temperature of from 300.degree. C. to 600.degree. C. is improved in the presence of (a) elemental tellurium or a tellurium compound which is in contact with said catalyst or in the presence of (a) elemental tellurium or a tellurium compound and (b) a molybdenum compound which are in contact with said catalyst. This activity improvement process can be applied to both the fresh catalysts and the spent catalyst having a deteriorated activity. The above described component (a) is preferably composed of a tellurium containing solid to be used in a state of a dry physical mixture with said catalyst. The above described components (a) and (b) are preferably composed of a tellurium containing solid and a molybdenum containing solid respectively or a tellurium-molybdenum containing solid to be used in a state of a dry physical mixture with said catalyst.

Abstract: Iron-antimony metallic oxide catalysts which have become deactivated after being used for the production of aldehydes, acids, nitriles, or dienes through oxidation, ammoxidation, or oxidative dehydrogenation of organic compounds in fluidized-bed reactors are regenerated by adding to the catalyst a molybdenum-enriched catalyst formed by supporting a molybdenum component which is volatile or capable of forming a volatile compound under reaction conditions on a metallic oxide catalyst. The metallic oxide catalysts contain as essential components (I) Fe, (II) Sb, (III) at least one element selected from the group consisting of V, Mo and W, and (IV) Te.

Abstract: A method for producing .alpha.,.alpha.-dimethyl-.delta.-valerolactone which comprises carrying out the addition reaction of hydrogen bromide and 2,2-dimethyl-4-pentenoic acid in the presence or absence of a catalyst to synthesize 2,2-dimethyl-5-bromovaleric acid which is then subjected to ring-closure reaction by alkali treatment.

Abstract: An improved grout impregnation method which uses an injection tube for contacting and mixing different kinds of materials supplied thereinto separately to prepare a grout and impregnates the grout into the earth through an injecting opening provided at a tip end of the tube.

Abstract: A stabilized fracturing fluid and a method of stabilizing a fracturing fluid containing at least one of guar gum and its derivatives is disclosed, wherein at least one stabilizing compound selected from the thiol derivatives of heterocyclic compounds is added to the fracturing fluid. This method of stabilization prevents degradation of the fracturing fluid, i.e., reduction in its rheological properties at high temperatures and permits smooth practice of the fracturing operation.

Abstract: A process for improving the activity of tellurium containing metal oxide catalysts useful as catalysts for oxidation, ammoxidation or oxidative dehydrogenation of organic compounds by heating the catalysts together with an activity-improving agent to a temperature up to about 900.degree. C. in a gaseous atmosphere. The process can be effectively applied to deteriorated or spent catalysts, the activity of which has been deteriorated due to use for a long period of time.

Abstract: A process for improving the activity of tellurium containing metal oxide catalysts useful as catalysts for oxidation, ammoxidation or oxidative dehydrogenation of organic compounds by heating the catalysts together with a tellurium containing solid and an optional molybdenum containing solid to a temperature up to about 900.degree. C. in a gaseous atmosphere. The process can be effectively applied to deteriorated or spent catalysts, the activity of which has been deteriorated due to use for a long period of time. The tellurium containing solid used as an activity improving agent is elemental tellurium and the molybdenum containing solid is selected from the group consisting of (i) a molybdenum compound, (ii) at least one molybdenum compound supported on an inert carrier, and (iii) a molybdenum enriched catalyst prepared by adding a Mo component to a metal oxide catalyst (which may be a fresh catalyst or a deteriorated catalyst).

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: A process for producing a modified hydroxyethyl cellulose comprising the steps of:allowing hydroxyethyl cellulose to be swollen in a solvent; andmixing the hydroxyethyl cellulose swollen in the solvent, with a 2-mercapto benzimidazole compound having the formula (I): ##STR1## wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 independently represent hydrogen, methyl, or ethyl, and X is hydrogen, an alkali metal, an alkaline earth metal, or ammonium.

Abstract: This invention deals with a process for manufacturing high purity silica which comprises making an aqueous alkali silicate solution into fine fibrous gel in a coagulant, treating the fibrous gel obtained with an acid-containing solution, and then with water to extract and remove impurities; and optionallly heating a resulting silica at a temperature of 1,000.degree. C. or higher. Thus obtained silica is preferably used as a filler, especially, the one for resin compositions for encapsulating electronic parts; etc.

Abstract: A stabilized fracturing fluid and a method of stabilizing a fracturing fluid containing at least one of guar gum and a derivative thereof is disclosed, comprising adding at least one stabilizing compound selected from 2-mercaptobenzimidazole and 2-mercaptobenzothiazole compounds to the fracturing fluid. This stabilization prevents degradation of the fracturing fluid, i.e., reduction in its rheological properties at high temperatures and permits smoothly carrying out the fracturing operation.

Abstract: A completion and workover fluid which comprises an aqueous liquid medium containing hydroxyethyl cellulose, an inorganic salt selected from the group consisting of calcium chloride, calcium bromide and zinc bromide, and a component selected from the group consisting of the following components:(1) thiol derivatives of heterocyclic compounds;(2) thioamide derivatives;(3) at least one compound selected from the group consisting of thiuram disulfide compounds, thiuram monosulfide compounds and dithiocarbamate compounds;(4) benzothiazole; and(5) a copper compound and an iodine compound in combination.

Abstract: A method for producing an aqueous silica sol is described, comprising admixing a fine silica powder having an ultimate particle size of 5 to 200 millimicrons with an aqueous medium at a pH not higher than 5 while applying ultrasonic vibrations having a frequency within the range of from 10 to 100 kilohertz to the aqueous medium to thereby disperse said silica powder in said aqueous medium and thus convert the mixture into an aqueous sol.