Studies on Melamine. I : Influence of Impurities on Direct Preparation of Melamine from Calcium Cyanamide

In the case of manufacturing melamine directly from calcium cyanamide of poor quality, the influence of impurities contained in the starting material has been studied

Studies on Melamine. IV : The Reaction Mechanism of the Formation of Melamine from Dicyandiamide

(1) In the case of preparing melamine from dicyandiamide in presence of liquid ammonia under pressure, the formation of guanidine as an intermeiate product was proved by isolating it as its picrate. (2) In the above case, dicyandiamide was therefore dissociated into cyanamide, which was fixed as guanidine by coexisting ammonia. The formation of melamine was assumed to be due to the polymerization of the three moles of cyanamide produced through guanidine or to the combination of cyanamide and dicyandiamide. The author wishes to express his hearty thanks to Professor Kotaro Shimo for his kind guidance and also to offer his best thanks to Mr. Tadashi Yamaguchi for his help in the experiments

Studies on Derivatives of Diphenylene Oxide. I. 2-Aminodiphenylene Oxide

The preparation of 2-aminodiphenylene oxideby ammonolysis of 2-halogenodiphenylene oxide，obtained by halogenation of diphenylene oxide，was studied. 2-Aminodiphenylene oxide (mp 124.5～50C) was best prepared by ammonolysis of 2- bromdiphenylene oxide of low purity (71% mp 87～95℃) under pressure (52-6kg/㎠) in 53.3% yield，which was obtained from bromination products of diphenylene oxide by vacuum distillation

On Some p-Substituted Benzoic Anhydrides

Some p-substituted benzoic anhydrides were prepared from corresponding p-substituted benzoic acid and acetic anhydride by the ordinary method. p-Chlorobenzoic anhydride (mp 190 -2°C)was obtained in almost quantitative yield and p-nitrobenzoic anhydride (mp 191 -2°C)， in 71% yield. p-Acetoxybenzoic anhydride (mp 78 -80°C) which has not been reported in the literature，was also synthesized as the above，by the reaction of p-acetoxybenzoic acid or p-oxybenzoic acid with acetic anhydride，but recrystalisation of the product was difficult. In order to confirm the formation of p-acetoxybenzoic anhydride accordingly， it was converted into p-oxybenzamide by warming with 28% aqueous ammonia or into p-acetoxybenzoic acid methyl ester by heating with methanol

Synthesis of Some o-Substituted Benzoic Anhydrides

Some o-substituted benzoic anhydrides were synthesized from corresponding o-substituted benzoic acid and acetic anhydride by the ordinary method.o-Chlorobenzoic anhydrids (mp 79~80℃)(Ⅰ) was obtained in yield of 91.4% by the reaction of o-Chlorobenzoic acid and acetic anhydride. Similarly， o-Nitrobenzoic anhydride (mp 133~50℃) (Ⅱ) was obtained in yield of 42% and o-acetoxybenzoic anhydride (acetylsalicy1ica anhydride，mp 83~40℃) (Ⅲ)，in yield of 55.2%. In order to confirm the formation ofⅠ,Ⅱ and Ⅲ, accordingly,they were converted into corresponding acidamides, o-Chlorobenzamide (mp 139~140℃，yield 95%)， o-nitrobenzamide (mp 173~50℃，yield 95.2%) and salicylamide (mp 138~138.5℃，yield 75%) were obtained respectively from Ⅰ,Ⅱ and Ⅲ by warming with 28% aqueous ammonia

Studies on Melamine Derivatives(II):Di- and Tri-benzoylmelamine

The purpose of this work was the study of benzoyIation of melamine with benzoic acid anhydride（BA）． A new compound，Dibenzoylmelamine（DBM）mp242－3℃ was obtained in23．7％ yield by refluxing monobenzoylmelamine（MBM）（1．8g）with BA（3．6g）in pyridine （180㏄）for 8hours，together with a small quantity of tribenzoylmelamine（TBM）． Similarly，MBM was prepared by refluxing melamine with BA（Mole ratio，1：2）in pyridine for 3hours，together with a small quantity of DBM．Also，TBM was obtained by treating DBM with BA（Mole ratio，l：2）in pyridine for 20hours，but the yield of TBM was poor. It was best obtained in 81％ yield by fusing melamine with BA（Mole ratio，1l：4．5）． The TBM gave various soIvation products with recrystalising solvent such as alcohol，dioxane，acetone and ethyl acetate．All of these solvation products regenerated TBM（mp 193－4℃）when they were dried at the respective boiling point of xylene or chlorobenzene under reduced pressure of 2mmHg