Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB28887/30A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
IG Farbenindustrie AG
Original Assignee
IG Farbenindustrie AG
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Filing date
Publication date
Application filed by IG Farbenindustrie AGfiledCriticalIG Farbenindustrie AG
Publication of GB364116ApublicationCriticalpatent/GB364116A/en
1 : 4 : 5 : 8-Naphthalene-tetracarboxylic acid is obtained by treating the corresponding di-imide with concentrated or fuming sulphuric acid at an elevated temperature, the di-imide being obtained by the process of Specification 362,906. According to an example, the di-imide is treated with concentrated sulphuric acid at 200-210 DEG , and the product precipitated. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the preparation of substitution products of 1 : 4 : 5 : 8-naphthalene-tetracarboxylic acid and the use of derivatives and substitution products of the di-imide as parent materials, and includes further examples in which the acid is obtained from the diphenyl- and dimethyl-di-imides respectively. This subject-matter does not appear in the Specification as accepted.
GB28887/30A1929-09-261930-09-26Manufacture of 1:4:5:8-naphthalene-tetra-carboxylic acid
ExpiredGB364116A
(en)