A method for producing an aromatic dianhydride includes reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst to provide an aqueous reaction mixture including an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt. The method further includes removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent using a single packed extraction column. The aromatic tetraacid salt is converted to the corresponding aromatic dianhydride. Aromatic dianhydrides prepared according to the method are also described.

The purpose of the present invention is to provide: a -conjugated compound exhibiting excellent light emission characteristics; an organic electroluminescent element using same; a display device; and an illumination device. Accordingly, this organic electroluminescent element is provided with: a positive electrode; a negative electrode; and at least one organic layer which is sandwiched between the positive electrode and the negative electrode, and which includes a light emission layer. The light emission layer includes a -conjugated compound having a structure represented by any of general formulae (1)-(3)

##STR00001##

(in general formulae (1)-(3), at least one among R1-R4, R5-R8, and R9-R16 represents a group represented by general formula (4)

##STR00002##

(in general formula (4): Ar1 and Ar2 represent substituted or unsubstituted aryl groups; L1 represents a single bond or a substituted or unsubstituted arylene group; and # represents a bond to general formulae (1)-(3))).

A method for manufacturing methyltetrahydrophthalic anhydride is provided, which includes steps as follows. Maleic anhydride is added into a reactor. Piperylene is added into the reactor, so that the piperylene and the maleic anhydride undergo a first addition reaction. When a conversion rate of the maleic anhydride is more than 25%, the first addition reaction is completed. Isoprene is added into the reactor, so that the isoprene and the maleic anhydride undergo a second addition reaction to obtain a methyltetrahydrophthalic anhydride product. The methyltetrahydrophthalic anhydride product contains 3-methyltetrahydrophthalic anhydride and 4-methyltetrahydrophthalic anhydride.

A method for manufacturing methyltetrahydrophthalic anhydride is provided, which includes steps as follows. Maleic anhydride is added into a reactor. Piperylene is added into the reactor, so that the piperylene and the maleic anhydride undergo a first addition reaction. When a conversion rate of the maleic anhydride is more than 25%, the first addition reaction is completed. Isoprene is added into the reactor, so that the isoprene and the maleic anhydride undergo a second addition reaction to obtain a methyltetrahydrophthalic anhydride product. The methyltetrahydrophthalic anhydride product contains 3-methyltetrahydrophthalic anhydride and 4-methyltetrahydrophthalic anhydride.

Shell-and-tube devices typically require regular maintenance. Described herein is an automated method for tracking the status of individual tubes during maintenance activities and recording status data for review and analysis. Status data may optionally be reported in real-time summary format and/or used to predict time-to-completion. The method helps to reduce the expense of performing maintenance activities in shell-and-tube devices, including shell-and-tube reactors and heat exchangers.

Shell-and-tube devices typically require regular maintenance. Described herein is an automated method for tracking the status of individual tubes during maintenance activities and recording status data for review and analysis. Status data may optionally be reported in real-time summary format and/or used to predict time-to-completion. The method helps to reduce the expense of performing maintenance activities in shell-and-tube devices, including shell-and-tube reactors and heat exchangers.

A method for producing an aromatic dianhydride includes reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst to provide an aqueous reaction mixture including an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt. The method further includes removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent for a first time period, at a first extraction temperature and subsequent to the first time period, extracting the aqueous reaction mixture with an organic solvent for a second time period, at a second extraction temperature. The aromatic tetraacid salt is converted to the corresponding aromatic dianhydride. Aromatic dianhydrides prepared according to the method are also described.

A method for producing an aromatic dianhydride includes reacting an aromatic diimide with a substituted or unsubstituted phthalic anhydride in an aqueous medium in the presence of an amine exchange catalyst to provide an aqueous reaction mixture including an N-substituted phthalimide, an aromatic tetraacid salt, and at least one of an aromatic triacid salt and an aromatic imide diacid salt. The method further includes removing the phthalimide from the aqueous reaction mixture by extracting the aqueous reaction mixture with an organic solvent for a first time period, at a first extraction temperature and subsequent to the first time period, extracting the aqueous reaction mixture with an organic solvent for a second time period, at a second extraction temperature. The aromatic tetraacid salt is converted to the corresponding aromatic dianhydride. Aromatic dianhydrides prepared according to the method are also described.

Described herein are oxygen scavengers, oxygen scavenging polymeric compositions, and oxygen scavenging articles. The polymeric compositions comprising the oxygen scavengers may have utility in packaging, sealing, wrapping, and storing oxygen-sensitive substances, e.g., to preserve freshness of foods, beverages, and the like.

Described herein are oxygen scavengers, oxygen scavenging polymeric compositions, and oxygen scavenging articles. The polymeric compositions comprising the oxygen scavengers may have utility in packaging, sealing, wrapping, and storing oxygen-sensitive substances, e.g., to preserve freshness of foods, beverages, and the like.