Due to solubility limitations, the highest dose tested for 4-aminobenzoic acid
was 600 [micro]g/ml and therefore this substance did not meet the EC ranges specified (> 1000), although it was correctly classified as negative.
5 g (36.47 mmol) of 4-aminobenzoic acid
was dissolved in 50 ml methanol and 4 ml sulfuric acid was added in it.
Procaine ([beta]-diethylaminoethyl ester of 4-aminobenzoic acid
hydrochloride) was purchased from Guangxi Shentai Chemical Co., Ltd., China.
The cross-linked solution was used in preparing the beads and then grafted with 4-aminobenzoic acid
to produce FGCX (Figure 2).
For synthesis of 4-carboxybenzenediazonium salt, 0.01 mol of 4-aminobenzoic acid
was dissolved in 20 mL of warm aqueous hydrochloride solution (0.22 M).
To achieve homogeneous dispersion of graphenes and strong interfacial bonding simple one step amine-functionalization of the pristine graphenes was performed via treating them in a solution of 4-aminobenzoic acid
and polyphosphoric acid.
can be easily converted to 4-carboxyphenyl diazonium salts by the diazotization reaction in acid aqueous solution at 0[degrees]C (Figure 2).
We purchased BT, HQ, and CT from Wako Pure Chemical Industries (Osaka, Japan); catalase from Boehringer-Mannheim (Mannheim, Germany); 4-aminobenzoic acid
hydrazide (ABAH) from Tokyo Chemical Industry (Tokyo, Japan); and methionine and sodium hypochlorite (NaOCl) from Nacalai Tesque (Kyoto, Japan).
Compound C18-silica PS-DVB PGC Benzene 2.20 3.50 1.45 Monosubstituted Aniline 1.10 2.50 1.35 Phenol 1.55 2.40 1.80 Benzoic acid 1.90 3.20 2.40 Nitrobenzene 2.05 3.60 2.45 Polysubstituted 4-Aminophenol - 1.10 2.05 1,4-Diaminobenzene - 1.20 2.40 4-Aminobenzoic acid
- 2.00 2.85 4-Hydroxybenzoic acid - 2.30 2.70 3,5-Dihydroxybenzoic acid - 1.35 3.00 1,3-Dihydroxybenzene - 1.35 2.35 1,4-Dihydroxybenzene - 0.85 2.15 1,3,5-Trihydroxybenzene - 0.50 2.70 -not retained TABLE 2.
The monosaccharides are pre-column derivatized with 4-aminobenzoic acid
ethyl ester by reductive amination to a secondary amine which absorbs at 306 nm.
It has also concluded that existing data on the approved use of 4-aminobenzoic acid
as a sunscreen needs reviewing, because much existing dossier information does "not confirm to current standards and guidelines".