Abstract: In a process for preparing p-dichlorobenzene by nuclear chlorination of benzene and/or chlorobenzene as the starting material with chlorine molecules, chlorination is carried out using aluminum chloride in an amount of 0.1–3 millimols per mol of the starting material and phenothiazines such as 10H-phenothiazine-10-carboxylic acid phenyl ester in an amount of 0.1–0.9 mols per mol of aluminum chloride so as to be a chlorination degree in a range of 1.2–2.5, by which p-dichlorobenzene can be obtained in a high para-selectivity and a short reaction time.

Abstract: 5-[(4-chlorophenyl)methyl]-2,2-dimethylcyclopentanone is produced by reacting 1-[(4-chlorophenyl)methyl]-3-methyl-2-oxocyclopentanecarboxylic acid methyl ester or 1-[(4-chlorophenyl)methyl]-3-methyl-2-oxocyclopentanecarboxylic acid ethyl ester with sodium hydride and methyl halide, then hydrolyzing the obtained 1-[(4-chlorophenyl)methyl]-3,3-dimethyl-2-oxocyclopentanecarboxylic acid methyl ester or 1-[(4-chlorophenyl)methyl]-3,3-dimethyl-2-oxocyclopentanecarboxylic acid ethyl ester. The process provides 5-[(4-chlorophenyl)methyl]-2,2-dimethylcyclopentanone, an important intermediate of an agricultural or horticultural fungicide, e.g., Metconazole.

Abstract: In a process for preparing p-dichlorobenzene by nuclear chlorination of benzene and/or chlorobenzene as the starting material with chlorine molecules, chlorination is carried out using aluminum chloride in an amount of 0.1-3 millimols per mol of the starting material and phenothiazines such as 10H-phenothiazine-10-carboxylic acid phenyl ester in an amount of 0.1-0.9 mols per mol of aluminum chloride so as to be a chlorination degree in a range of 1.2-2.5, by which p-dichlorobenzene can be obtained in a high para-selectivity and a short reaction time.

Abstract: The optical material in accordance with the present invention contains a specific phosphonate monoester compound such as monoethyl 3-methoxy butyl phosphonate, and a metal ion such as a copper ion or rare-earth metal ion. They may be contained in a solvent or resin. The use of such a specific phosphonate monoester compound improves the compatibility with a resin, whereby the metal ion can favorably be dispersed into the resin. Consequently, spectral characteristics can be improved when the optical member is formed into a resin-made optical member.

Abstract: The optical material in accordance with the present invention contains a specific phosphonate monoester compound such as monoethyl 3-methoxybutyl phosphonate, and a metal ion such as a copper ion or rare-earth metal ion. They may be contained in a solvent or resin. The use of such a specific phosphonate monoester compound improves the compatibility with a resin, whereby the metal ion can favorably be dispersed into the resin. Consequently, spectral characteristics can be improved when the optical member is formed into a resin-made optical member.

Abstract: A magnetic tape cassette is provided with a pivotal closure lid pivotably secured to both sides of a casing for movement between a closed position, in which the front opening of the casing, through which a magnetic tape is accessible for loading onto a rotary head, is covered, and an open position wherein the closure lid is pivoted away from said opening to expose the tape while the cassette is in use. The magnetic tape cassette is also provided with a sliding closure member slidably mounted on the bottom of the casing and cooperative with the aforementioned pivotal closure lid. The sliding closure member is in a closed position while the pivotal closure lid is in its closed position, in which it covers a bottom clearance through which a device constituting part of a tape holding system is inserted, and in an open position while the pivotal closure lid is in its open position to allow the aforementioned device of the tape handling system to reach into the casing through the bottom clearance.

Abstract: A magnetic tape cassette is provided with a pivotal closure lid pivotably secured to both sides of a casing for movement between a closed position, in which the front opening of the casing, through which a magnetic tape is accessible for loading onto a rotary head, is covered, and an open position wherein the closure lid is pivoted away from said opening to expose the tape while the cassette is in use. The magnetic tape cassette is also provided with a sliding closure member slidably mounted on the bottom of the casing and cooperative with the aforementioned pivotal closure lid. The sliding closure member is in a closed position while the pivotal closure lid is in its closed position, in which it covers a bottom clearance through which a device constituting part of a tape holding system is inserted, and in an open position while the pivotal closure lid is in its open position to allow the aforementioned device of the tape handling system to reach into the casing through the bottom clearance.

Abstract: A magnetic tape cassette is provided with a pivotal closure lid pivotably secured to both sides of a casing for movement between a closed position, in which the front opening of the casing, through which a magnetic tape is accessible for loading onto a rotary head, is covered, and an open position wherein the closure lid is pivoted away from said opening to expose the tape while the cassette is in use. The magnetic tape cassette is also provided with a sliding closure member slidably mounted on the bottom of the casing and cooperative with the aforementioned pivotal closure lid. The sliding closure member is in a closed position while the pivotal closure lid is in its closed position, in which it covers a bottom clearance through which a device constituting part of a tape holding system is inserted, and in an open position while the pivotal closure lid is in its open position to allow the aforementioned device of the tape handling system to reach into the casing through the bottom clearance.