Abstract: Disclosed is a method for extracting methacrylic acid, in which an extraction solvent is added to a methacrylic acid aqueous solution for transferring methacrylic acid to the extraction solvent. In this method, a solvent containing t-butyl methacrylate is used as the extraction solvent.

Abstract: Disclosed is a method for synthesizing t-butyl (meth)acrylate at low cost. Specifically, disclosed is a method for synthesizing a carboxylic acid ester by performing an addition reaction between isobutylene and (meth)acrylic acid in the presence of an acidic catalyst. This method includes the steps of: (A) performing a dehydration decomposition reaction of t-butyl alcohol in the presence of a first acidic catalyst; (B) obtaining crude isobutylene gas by separating at least water from a produced gas obtained in the step A; (C) absorbing the crude isobutylene gas in an absorption solvent containing (meth)acrylic acid; and (D) producing t-butyl (meth)acrylate by performing the addition reaction by bringing the absorption solvent which has absorbed the crude isobutylene gas into contact with a second acidic catalyst.

Abstract: Disclosed is a method for extracting methacrylic acid, in which an extraction solvent is added to a methacrylic acid aqueous solution for transferring methacrylic acid to the extraction solvent. In this method, a solvent containing t-butyl methacrylate is used as the extraction solvent.

Abstract: Disclosed is a method for producing tertiary butyl alcohol through hydration reaction of isobutylene and water in the presence of a cation exchange resin by using a reactor having at least two reactor vessels provided in series. The method is characterized in that a fluid in a reactor vessel at the most downstream side forms a two-liquid phase and the reaction temperature of the reactor vessel is kept at 70° C. or lower, and a fluid in at least one reactor vessel other than the one at the most downstream side forms a homogeneous phase.

Abstract: Disclosed is a method for producing tertiary butyl alcohol through hydration reaction of isobutylene and water in the presence of a cation exchange resin by using a reactor having at least two reactor vessels provided in series. The method is characterized in that a fluid in a reactor vessel at the most downstream side forms a two-liquid phase and the reaction temperature of the reactor vessel is kept at 70° C. or lower, and a fluid in at least one reactor vessel other than the one at the most downstream side forms a homogeneous phase.

Abstract: Disclosed is a method for synthesizing t-butyl (meth)acrylate at low cost. Specifically, disclosed is a method for synthesizing a carboxylic acid ester by performing an addition reaction between isobutylene and (meth)acrylic acid in the presence of an acidic catalyst. This method includes the steps of: (A) performing a dehydration decomposition reaction of t-butyl alcohol in the presence of a first acidic catalyst; (B) obtaining crude isobutylene gas by separating at least water from a produced gas obtained in the step A; (C) absorbing the crude isobutylene gas in an absorption solvent containing (meth)acrylic acid; and (D) producing t-butyl (meth)acrylate by performing the addition reaction by bringing the absorption solvent which has absorbed the crude isobutylene gas into contact with a second acidic catalyst.

Abstract: There is provided a powdery S,S-EDDS iron complex improved in its caking property. An S,S-ethylenediamine-N,N?-disuccinic acid iron complex, which is crystalline and has an average particle diameter of from 10 to 1000 ?m and a water content of not more than 7% by weight, a powdery S,S-ethylene-N,N?-disuccinic acid (S,S-EDDS) iron complex having a compressive strength of not more than 1 kg/cm2, the compressive strength being measured according to JIS A 1108 after a lapse of 2 months under conditions of a temperature of 50° C. and a load of 300 g/cm2, and a process for producing the same.

Abstract: Crystals of [S,S]-ethylenediamine-N,N′-disuccinic acid which have a bulk density of 0.45 to 1.2 g/cm3, and a process for obtaining these crystals comprising the steps of adjusting an aqueous solution of an [S,S]-ethylenediamine-N,N′-disuccinic acid metal salt to a temperature of 40 to 80° C. and a pH of 1.9 to 4.5, and cooling the solution to a temperature below 40° C. over a period of 0.2 to 10 hours while supplying a mineral acid so as to maintain the pH at 1.9 to 4.5 to precipitate [S,S]-ethylenediamine-N,N′-disuccinic acid in a high yield.

Abstract: Crystals of [S,S]-ethylenediamine-N,N′-disuccinic acid which have a bulk density of 0.45 to 1.2 g/cm3, and a process for obtaining these crystals comprising the steps of adjusting an aqueous solution of an [S,S]-ethylenediamine-N,N′-disuccinic acid metal salt to a temperature of 40 to 80° C. and a pH of 1.9 to 4.5, and cooling the solution to a temperature below 40° C. over a period of 0.2 to 10 hours while supplying a mineral acid so as to maintain the pH at 1.9 to 4.5 to precipitate [S,S]-ethylenediamine-N,N′-disuccinic acid in a high yield.

Abstract: Crystals of [S,S]-ethylenediamine-N,N′-disuccinic acid which have a bulk density of 0.45 to 1.2 g/cm3, and a process for obtaining these crystals comprising the steps of adjusting an aqueous solution of an [S,S]-ethylenediamine-N,N′-disuccinic acid metal salt to a temperature of 40 to 80° C. and a pH of 1.9 to 4.5, and cooling the solution to a temperature below 40° C. over a period of 0.2 to 10 hours while supplying a mineral acid so as to maintain the pH at 1.9 to 4.5 to precipitate [S,S]-ethylenediamine-N,N′-disuccinic acid in a high yield.

Abstract: An apparatus for monitoring torsional vibrations of a rotating shaft system such as for a turbine generator in which torsional vibrations at certain positions of the rotating shaft system are detected by detectors and the detected vibrations are converted into torsional vibration at an arbitrary position of the rotating shaft system by using an operation device having desired transfer characteristics, said arbitrary position is monitored on torsional vibration on the basis of the converted torsional vibration.

Abstract: The present invention relates to a torsional vibration monitoring apparatus for a rotating shaft system which is characterized by comprising a detector disposed at a certain position of the rotating shaft system for detecting torsional vibration of the shaft system, a memory device for storing the torsional vibration having a constant time duration which is detected by the detector as a time series data obtained by sampling the torsional vibration with minute unit times, a Fourier transforming device for Fourier-transforming the time series data to obtain a frequency series data, multiplier each for multiplying the frequency series data with a relation which is previously obtained between the vibration of the shaft system at the certain position of the shaft system and that at an arbitrary position thereof at respective frequencies to obtain a frequency series data for the arbitrary position, and reverse Fourier transformer for reverse-Fourier-transforming the frequency series data to obtain a time series dat

Abstract: A torsional vibration monitoring system for monitoring torsional vibration occurring in a rotating shaft system such as in a power generator turbine is disclosed. Torsional vibrations are measured at a small number of measurable positions on the rotating shaft system, and stresses at other arbitrary positions are estimated by linearly decomposing the torsional vibrations. The fatigue life expenditure on the rotating shaft system is obtained and monitored on the basis of the estimation obtained by the linear decomposition of the torsional vibration. For a huge vibration such as caused by thunder which may produce stresses on the rotating shaft system and which can not be estimated by the linear decomposition thereof, the torsional vibration monitoring apparatus may be provided with means to produce data which may be used in other analysis, by recording real torsional vibrations caused thereby.