Abstract: An industrially advantageous process for producing optically active 4-amino-2-methylbutane-1-ol which is useful as an intermediate in synthesizing optically active medicines and pesticides. Racemic 4-amino-2-methylbutane-1-ol is treated with an optically active organic acid. The diastereomeric salt thus obtained is crystallized out and subjected to solid-liquid separation to give optically active 4-amino-2-methylbutane-1-ol. The diastereomeric salt of optically active 4-amino-2-methylbutane-1-ol with an optically active reagent for optical resolution is decomposed by bringing into contact with a solvent and an alkali and subjected to solid-liquid separation, thereby recovering the optically active 4-amino-2-methylbutane-1-ol from the filtrate. Further, the filtration residue containing the alkali salt of the reagent for optical resolution obtained by the solid-liquid separation is brought into contact with a solvent and an acid.

Abstract: A process for producing an .alpha.-hydroxy acid or an .alpha.-hydroxyamide which comprises treating an aldehyde and prussic acid or an .alpha.-hydroxynitrile with a microorganism having nitrilase or nitrile hydratase activity in an aqueous medium and maintaining the aldehyde concentration and/or the .alpha.-hydroxynitrile concentration in the reaction mixture within a predetermined range. Also disclosed is a process for producing an .alpha.-hydroxy acid or an .alpha.-hydroxyamide from an aldehyde and prussic acid with a microorganism in an aqueous medium, which comprises maintaining the cyanogen concentration in the reaction mixture within a predetermined range and supplying the aldehyde to the reaction mixture at a predetermined ratio to the prussic acid.

Abstract: A method for producing a nonsintered cristobalite particles comprising heating amorphous silica particles at a temperature of 1400.degree. to 1700.degree. C. in the presence of cristobalite particles (hereinafter referred to as cristobalite particles for addition and mixing) of at least 5 parts by weight based on 100 parts by weight of said amorphous silica particles to convert said amorphous silica particles to cristobalite particles with their particle form kept unchanged. According to the present invention, dense cristobalite having a low alkali content can be obtained in the form of particles. Such cristobalite is used as a filler, a dispersing agent, etc., and also as a material for high-quality artificial quartz, ceramics, etc., and particularly as a material for transparent quartz glass because of its generating no bubbles at the time of melt-molding.

Abstract: A method of manufacturing spherical silica particles comprising the steps of processing in an acid-containing solution and then washing with water the coagulant derived from an aqueous alkali metal silicate solution extruded through pores in a water-miscible organic medium or acid solution, wet-grinding the amorphous silica thus obtained in a liquid dispersion medium to obtain a fine particle silica suspension with a weight average particle size of 10 .mu.m or less, spray-drying this fine particle silica suspension with hot air and sintering the spherical granulated silica thus obtained. According to the present invention, the high-purity spherical silica particles can be obtained with high solidity and adjusted surface smoothness without any complicated operation or waste water treatment for use as a sealant filler for highly-integrated IC electronic parts.

Abstract: A process for producing 2,6-dichlorobenzonitrile by ammoxidation comprising contacting a starting gas consisting of 2,6-dichlorotoluene, air and ammonia, which comprises carrying out this reaction under the following conditions:(a) the concentration of 2,6-dichlorotoluene in the starting gas is 2.6 mole % or more.(b) the reactor effluent gas is contacting with water to cool to a temperature in the range of 50.degree. to 90.degree. C., whereby 2,6-dichlorobenzonitrile in the reactor effluent gas is collected as a slurry in which solidified 2,6-dichlorobenzonitrile is dispersed in water, and 2,6-dichlorobenzonitrile is obtained from the slurry, and(c) the cooled reactor effluent gas from which 2,6-dichlorobenzonitrile has been removed is contacted with water again to cool to a temperature in the range of 0.degree. to 40.degree. C., whereby unreacted 2,6-dichlorotoluene in the gas is collected as a dispersion in which it is dispersed in water and 2,6-dichlorotoluene is recovered from the dispersion.

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 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 the continuous production of acrylamide or methacrylamide from acrylonitrile or methacrylonitrile by use of a microorganism capable of promoting the hydration of acrylonitrile or methacrylonitrile into the corresponding amide.Said process comprising immobilizing the microorganism or enzyme extracted therefrom, continuously bringing the acrylonitrile or methacrylonitrile into contact with the immobilized microorganism or enzyme in at least one reactor containing an aqueous medium at a pH pf 6 to 10 to cause the hydration reaction, and recycling a part of the reacted solution to dilute the unreacted acrylonitrile or methacrylonitrile and water therewith.

Abstract: A process for producing acrylamide from acrylonitrile by utilizing a microorganism or enzyme capable of hydrating acrylonitrile into acrylamide in the form of a highly concentrated aqueous solution of acrylamide which comprises bringing acrylonitrile in contact with the microorganism or enzyme in an aqueous medium at a pH of from 6 to 10, at a temperature of from the freezing point to 50.degree. C., and under such conditions that the concentration of acrylamide in the reaction solution after the completion of the reaction is from 5% by weight to less than 20% by weight, and concentrating the resulting reaction solution; this invention further includes an embodiment wherein the reaction solution is concentrated by cooling the reaction solution after the reaction to from -4.degree. C. to -9.degree. C. to crystallize ice, separating the ice, and using the ice so separated for cooling during the hydration reaction.

Abstract: A process for preparing an aqueous solution of acrylamide, which comprisescatalytically hydrating acrylonitrile in the presence of a metal-containing catalyst to form a mixed aqueous solution containing about 15 to about 35% by weight of acrylamide and about 0.5 to about 20% by weight of acrylonitrile, andconcentrating the mixed aqueous solution to a high concentration aqueous solution of acrylamide having an acrylonitrile concentration of about 0.1% by weight or less using a centrifugal film evaporator in which a stream of mixed aqueous solution and a stream of evaporated vapor flow countercurrently to each other.

Abstract: An anti-halation layer for photographic materials comprising at least one first binder which is swollen by an aqueous alkaline solution and comprises about 10 to about 25% by weight of alkyl acrylate units, 52 to 65% by weight of alkyl methacrylate units and about 18 to about 30% by weight of suitable acid monomer units, and at least a second binder agent which is soluble in an alkaline aqueous solution but which can withstand a strongly alkaline preliminary bath and is readily stripped away only at a successive rinsing operation.