Abstract: The present invention provides an ion-exchange resin catalyst, as a catalyst for preparing bisphenol from phenol compounds and ketone, which has a higher selectivity to bisphenol and a longer life time, as compared to a conventional ion-exchange resin, and a method for preparing the same. The present invention also provides a method for preparing bisphenol comprising reacting phenol compounds with ketone, wherein the modified acidic ion-exchange resin in which at least one kind of cationic compound selected from the following (a), (b), (c) and (d) ionically binds to an acidic functional group, is used as a catalyst: (a) a quaternary phosphonium ion, (b) a quaternary ammonium ion, (c) a bis(phosphoranylidene) ammonium ion, and (d) an N-substituted nitrogen-containing aromatic cation.

Abstract: There is provided a modified ion exchange resin catalyst which exhibits higher bisphenols selectivity than the conventional modified ion exchange resins in processes wherein bisphenols are produced by reacting a phenolic compound with ketones, and to provide such a process for producing bisphenols.

Abstract: The present invention provides a process for producing bisphenol A by reacting phenol with actone, wherein reaction is performed at higher temperatures while maintaining high selectivity, and thus high productivity is obtained. The invention relates to a cation-exchange resin, wherein a cation-exchange group is introduced into a syndiotactic polystyrene polymer and the amount of acid is 0.8 milliequivalent/g or more, to a catalyst comprising the cation-exchange resin, and to a process for producing bisphenol A using a cation-exchange resin catalyst.

Abstract: There is provided a modified ion exchange resin catalyst which exhibits higher bisphenols selectivity than the conventional modified ion exchange resins in processes wherein bisphenols are produced by reacting a phenolic compound with ketones, and to provide such a process for producing bisphenols.

Abstract: There is provided a modified ion exchange resin catalyst which exhibits higher bisphenols selectivity than the conventional modified ion exchange resins in processes wherein bisphenols are produced by reacting a phenolic compound with ketones, and to provide such a process for producing bisphenols.

Abstract: There is provided a modified ion exchange resin catalyst which exhibits higher bisphenols selectivity than the conventional modified ion exchange resins in processes wherein bisphenols are produced by reacting a phenolic compound with ketones, and to provide such a process for producing bisphenols.

Abstract: The present invention provides a process for producing bisphenol A by reacting phenol with actone, wherein reaction is performed at higher temperatures while maintaining high selectivity, and thus high productivity is obtained. The invention relates to a cation-exchange resin, wherein a cation-exchange group is introduced into a syndiotactic polystyrene polymer and the amount of acid is 0.8 milliequivalent/g or more, to a catalyst comprising the cation-exchange resin, and to a process for producing bisphenol A using a cation-exchange resin catalyst.

Abstract: The present invention provides an ion-exchange resin catalyst, as a catalyst for preparing bisphenol from phenol compounds and ketone, which has a higher selectivity to bisphenol and a longer life time, as compared to a conventional ion-exchange resin, and a method for preparing the same. The present invention also provides a method for preparing bisphenol comprising reacting phenol compounds with ketone, wherein the modified acidic ion-exchange resin in which at least one kind of cationic compound selected from the following (a), (b), (c) and (d) ionically binds to an acidic functional group, is used as a catalyst: (a) a quaternary phosphonium ion, (b) a quaternary ammonium ion, (c) a bis(phosphoranylidene) ammonium ion, and (d) an N-substituted nitrogen-containing aromatic cation.

Abstract: There is provided a modified ion exchange resin catalyst which exhibits higher bisphenols selectivity than the conventional modified ion exchange resins in processes wherein bisphenols are produced by reacting a phenolic compound with ketones, and to provide such a process for producing bisphenols.

Abstract: The present invention provides a process for producing bisphenol A by reacting phenol with acetone, wherein reaction is performed at higher temperatures while maintaining high selectivity, and thus high productivity is obtained. The invention relates to a cation-exchange resin, wherein a cation-exchange group is introduced into a syndiotactic polystyrene polymer and the amount of acid is 0.8 milliequivalent/g or more, to a catalyst comprising the cation-exchange resin, and to a process for producing bisphenol A using the cation-exchange resin catalyst.

Abstract: The present invention provides an ion-exchange resin catalyst, as a catalyst for preparing bisphenol from phenol compounds and ketone, which has a higher selectivity to bisphenol and a longer life time, as compared to a conventional ion-exchange resin, and a method for preparing the same. The present invention also provides a method for preparing bisphenol comprising reacting phenol compounds with ketone, wherein the modified acidic ion-exchange resin in which at least one kind of cationic compound selected from the following (a), (b), (c) and (d) ionically binds to an acidic functional group, is used as a catalyst: (a) a quaternary phosphonium ion, (b) a quaternary ammonium ion, (c) a bis(phosphoranylidene) ammonium ion, and (d) an N-substituted nitrogen-containing aromatic cation.

Abstract: The present invention provides a process for preparing bisphenol A with a high conversion and selectivity by reacting phenol with acetone in the presence of both a polyorganosiloxane having a mercapto group-containing hydrocarbon group and an acid. It is preferable that the polyorganosiloxane having a mercapto group-containing hydrocarbon group and the acid is a polyorganosiloxane having both a mercapto group-containing hydrocarbon group and a sulfonic acid group.

Abstract: A control circuit is used during slow or stop-motion playback operation of a video tape device to drive video tape intermittently. In order to avoid errors in the stopping position of the tape, a pulse width modulated (PWM) signal is provided to a motor controller circuit associated with the capstan motor of the video tape device. A frequency signal generator coupled to this motor generates a frequency signal that varies with the capstan motor speed, and this frequency signal is provided to a retrigger monostable multivibrator which generates a PWM signal whose duty ratio changes in proportion to the capstan motor speed. A drive pulse generator and a brake pulse generator provide drive start and brake start signals, respectively, when it is desired to commence and stop movement of the tape.