5-Nitro-1-benzofuran-2(3H)-one.

In the crystal structure of the title compound, C(8)H(5)NO(4), essentially planar mol-ecules [largest deviation from the least-squares plane = 0.030 (2) Å] form stacks along the a-axis direction. Intercentroid separations between overlapping benzene rings within the stack are 3.6594 (12) Šand 3.8131 (12) Å. Mol-ecules from neighboring stacks are linked by weak C-H⋯O hydrogen bonds into inversion dimers.

Ethyl 2-(2-hy-droxy-5-nitro-phen-yl)acetate.

In the crystal structure of the title compound, C(10)H(11)NO(5), inter-molecular O-H⋯O hydrogen bonds link the mol-ecules into chains along the b-axis direction. Weak C-H.·O hydrogen bonds also occur.

2-Methyl-4-(2-methyl-benzamido)-benzoic acid.

In the crystal structure of the title compound, C(16)H(15)NO(3), inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into chains parallel to the b axis and pairs of inter-molecular O-H⋯O hydrogen bonds between inversion-related carb-oxy-lic acid groups link the mol-ecules into dimers. The dihedral angle between the two benzene rings is 82.4 (2)°.

Ethyl 2-[1,3-dioxo-6-(piperidin-1-yl)-2,3-dihydro-1H-benz[de]isoquinolin-2-yl]acetate.

In the title compound, C(21)H(22)N(2)O(4), the naphthalimide unit is almost planar (r.m.s. deviation = 0.081Å). The carboximide N atom and the five C atoms of the eth-oxy-carbonyl-methyl substituent also lie close to a common plane (r.m.s. deviation = 0.119Å), which subtends an angle of 71.06 (8)° to the naphthalamide plane. The piperidine ring adopts a chair conformation. In the crystal, inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into zigzag chains along the a axis.

Methyl 4-(3-chloro-prop-oxy)benzoate.

In the crystal structure of the title compound, C(11)H(13)ClO(3), inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into zigzag chains along the c axis.

Methyl 5-chloro-2-(4-methyl-benzene-sulfonamido)-benzoate.

In the title compound, C(15)H(14)ClNO(4)S, the benzene rings are oriented at a dihedral angle of 85.42 (1)°. An intra-molecular N-H⋯O hydrogen bond results in the formation of a five-membered ring and an intramolecular C-H⋯O inter-action also occurs.

Methyl 5-chloro-2-[N-(3-eth-oxy-carbonyl-prop-yl)-4-methyl-benzene-sulfonamido]-benzoate.

In the title compound, C(21)H(24)ClNO(6)S, the benzene rings are oriented at a dihedral angles of 41.6 (2)°. In the crystal structure, weak inter-molecular C-H⋯O inter-actions link the mol-ecules.

2,2,2-Trifluoro-ethyl 4-methyl-benzene-sulfonate.

In the crystal structure of the title compound, C(9)H(9)F(3)O(3)S, inter-molecular C-H⋯O hydrogen bonds link the mol-ecules along the c-axis direction. Also present are slipped π-π stacking inter-actions between phenyl-ene rings, with perpendicular inter-planar distances of 3.55 (2) Šand centroid-centroid distances of 3.851 (2) Å.

Methyl 2-amino-5-chloro-benzoate.

The title compound, C(8)H(8)ClNO(2), is almost planar, with an r.m.s. deviation of 0.0410 Šfrom the plane through the non-hydrogen atoms. In the crystal structure, inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into chains along the b axis. An intra-molecular N-H⋯O hydrogen bond results in the formation of a six-membered ring.

Effective treatment of levofloxacin wastewater by an electro-Fenton process with hydrothermal-activated graphite felt as cathode.

The performance of the cathode significantly affects the ability of the electro-Fenton (EF) process to degrade chemicals. In this study, a simple method to modify the graphite felt (GF) cathode was proposed, i.e. oxidizing GF by hydrothermal treatment in nitric acid. The surface physical and electrochemical properties of modified graphite felt were characterized by several techniques: scanning electron microscope (SEM), water contact angle, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and linear scanning voltammetry (LSV). Compared with an unmodified GF (GF-0), the oxygen reduction reaction (ORR) activity of a modified GF was significantly improved due to the introduction of more oxygen-containing functional groups (OGs). Furthermore, the results showed that GF was optimally modified after 9 h (GF-9) of treatment. As an example, the H2O2 generation by GF-9 was 2.26 times higher than that of GF-0. After optimizing the process parameters, which include the initial Fe2+ concentration and current density, the apparent degradation rate constant of levofloxacin (LEV) could reach as high as 0.40 min-1. Moreover, the total organic carbon (TOC) removal rate and mineralization current efficiency (MCE) of the modified cathode were much higher than that of the GF-0. Conclusively, GF-9 is a promising cathode for the future development in organic pollutant removal via EF.