摘要:
The present invention provides a polyvinyl alcohol powder which comprises a pore having an average diameter of 0.1 to 10 .mu.m in the range of 0.05 to 0.4 cc/g. Since the PVA powder of the present invention has an excellent solubility in water, an aqueous solution thereof can easily be prepared industrially.Since the PVA powder of the present invention has a low content of an organic volatile component and a low content of a nonvolatile component such as a carboxylic acid salt or the like which is derived from a basic catalyst, it has an excellent industrial handleability.
摘要:
Process for producing ethylene-vinyl ester copolymers using a polymerization solvent of a dialkyl sulfoxide (process X); process for producing ethylene-vinyl alcohol copolymer by liquid phase saponification using a solvent of a dialkyl sulfoxide (process Y); and process for producing shaped articles which comprises contacting the ethylene-vinyl alcohol copolymer obtained by the process Y, or that obtained by saponifying the ethylene-vinyl ester copolymer obtained by process X, to a non-solvent for ethylene-vinyl alcohol copolymer.Ethylene-vinyl ester copolymers having a wide range of ethylene content and higher degree of polymerization than that with solution polymerization using methanol.The rate of saponification is higher than that with single solvent system of lower alcohol.Production cost is low, because production process of polymer is directly connected to that of shaped articles utilizing the polymer.
摘要:
Process for producing ethylene-vinyl ester copolymers using a polymerization solvent of a dialkyl sulfoxide (process X); process for producing ethylene-vinyl alcohol copolymer by liquid phase saponification using a solvent of a dialkyl sulfoxide (process Y); and process for producing shaped articles which comprises contacting the ethylene-vinyl alcohol copolymer obtained by the process Y, or that obtained by saponifying the ethylene-vinyl ester copolymer obtained by process X, to a non-solvent for ethylene-vinyl alcohol copolymer.Ethylene-vinyl ester copolymers having a wide range of ethylene content and higher degree of polymerization than that with solution polymerization using methanol.The rate of saponification is higher than that with single solvent system of lower alcohol.Production cost is low, because production process of polymer is directly connected to that of shaped articles utilizing the polymer.
摘要:
Activated carbon useful as polarizable electrode material for an electric double-layer capacitor can be obtained by mixing a carbonaceous material and an alkali metal hydroxide while maintaining a solid state, granulating the obtained mixture while maintaining its solid state, dehydrating the obtained granulated substance while maintaining its solid state, and subjecting the granulated dehydration product obtained in the dehydration step to an activation treatment. The preferred pressure of the granulation treatment in the granulation step is 0.01 to 300 Torr, and the preferred temperature of the granulation treatment is 90 to 140° C. The preferred pressure of the dehydration treatment in the dehydration step is 0.01 to 10 Torr, and the preferred temperature of the dehydration treatment is 200 to 400° C.
摘要:
The present invention provides an evaporated fuel gas adsorbent, an evaporated fuel gas trapping apparatus that uses the adsorbent, an activated carbon, and a process for producing the activated carbon. The evaporated fuel gas adsorbent is capable of improving adsorptivity and desorptivity by reliably preventing a temperature rise and a temperature fall caused by heat generated in response to the adsorption and desorption of evaporated fuel gas, is capable of achieving a size reduction of the device, and is capable of being easily produced. The activated carbon has high mechanical strength and high abrasive resistance, has many pores suitable to adsorb an organic solvent, especially, evaporated fuel gas, and has a high packing density. The activated-carbon producing process is industrially advantageous. The evaporated fuel gas adsorbent comprises an adsorptive material and latent heat storage mediums including containers each of which is made of a flexible film and in each of which a substance that absorbs or releases heat in response to a phase change is encased. The activated carbon is characterized in that a specific surface area calculated by a BET method (multipoint method) in a nitrogen adsorption isotherm determined from a nitrogen adsorption amount at liquid nitrogen temperature is 1000 to 2500 m2/g, in that a half-value width of a D-band peak in the neighborhood of 1360 cm−1 in Raman spectroscopic analysis is 120 cm−1 or less, and in that a half-value width of a G-band peak in the neighborhood of 1580 cm−1 in Raman spectroscopic analysis is 100 cm−1 or less.
摘要:
A material for improving the sound pressure level at the bass reproduction limit of the present invention is composed of an activated carbon having a cumulative pore volume of 0.4 ml/g or more for the pores each having a radius of 50 angstroms or less. Preferably, this activated carbon has a cumulative pore volume of 0.1 ml/g or less for the pores each having a radius of 7 angstroms or less. In particular, when a sound pressure level improving material in which the activated carbon has a cumulative pore volume of 0.5 ml/g or more for the pores each having a radius of 18 angstroms or less is installed in a cabinet of a loudspeaker device, the material alleviates pressure fluctuations of a gas within the cabinet caused by vibration of a loudspeaker, and thus a very good bass reproduction effect is attained. Moreover, in the case where a sound pressure level improving material in which the activated carbon has a cumulative pore volume of 0.4 ml/g or more for the pores each having a radius of 18 to 50 angstroms is installed in the cabinet, a loudspeaker device having a good bass reproduction effect even in an atmosphere of high humidity is obtained.
摘要:
There is provided a method of producing L-phenylalanine in high optical purity which comprises treating an N-acylphenylalanine alkyl ester in L form, in the presence of water, with an enzyme capable of hydrolyzing the N-acylphenylalanine alkyl ester in L form to give L-phenylalanine.
摘要:
A process for producing methyl lactate by (I) hydroformylating vinyl acetate or vinyl propionate with a gaseous mixture of hydrogen and carbon monoxide in an organic solvent in the presence of a substantially water-insoluble rhodium complex and a tri-substituted phosphine to form .alpha.-acetoxy- or propionyloxy-propionaldehyde, (II) subjecting at least part of the reaction mixture obtained in step (I) to extraction with an aqueous medium to obtain an aqueous layer containing .alpha.-acetoxy- or propionyloxy-propionaldehyde and an extraction residue containing the catalyst components, and recycling the extraction residue to the hydroformylation step (I), (III) separating .alpha.-acetoxy- or propionyloxy-propionaldehyde from the aqueous layer containing the same as obtained in step (II), (IV) oxidizing .alpha.-acetoxy- or propionyloxy-propionaldehyde obtained in step (III) in the liquid phase with oxygen gas or an oxygen-containing gas in the presence of an oxidation catalyst to form .alpha.-acetoxy- or propionyloxy-propionic acid, and (V) reacting .alpha.-acetoxy- or propionyloxy-propionic acid obtained in step (IV) with methanol in the presence of an acid catalyst, and recovering the resultant methyl lactate by distillation.
摘要:
The present invention provides an evaporated fuel gas adsorbent, an evaporated fuel gas trapping apparatus that uses the adsorbent, an activated carbon, and a process for producing the activated carbon. The evaporated fuel gas adsorbent is capable of improving adsorptivity and desorptivity by reliably preventing a temperature rise and a temperature fall caused by heat generated in response to the adsorption and desorption of evaporated fuel gas, is capable of achieving a size reduction of the device, and is capable of being easily produced. The activated carbon has high mechanical strength and high abrasive resistance, has many pores suitable to adsorb an organic solvent, especially, evaporated fuel gas, and has a high packing density. The activated-carbon producing process is industrially advantageous.
摘要:
Activated carbon useful as polarizable electrode material for an electric double-layer capacitor can be obtained by mixing a carbonaceous material and an alkali metal hydroxide while maintaining a solid state, granulating the obtained mixture while maintaining its solid state, dehydrating the obtained granulated substance while maintaining its solid state, and subjecting the granulated dehydration product obtained in the dehydration step to an activation treatment. The preferred pressure of the granulation treatment in the granulation step is 0.01 to 300 Torr, and the preferred temperature of the granulation treatment is 90 to 140° C. The preferred pressure of the dehydration treatment in the dehydration step is 0.01 to 10 Torr, and the preferred temperature of the dehydration treatment is 200 to 400° C.