The title compound consists of two planar halves. There is one half-mol­ecule in the asymmetric unit, the whole mol­ecule being generated by twofold rotation symmetry. The crystal structure has wide channels of 5–6 Å in diameter extending along the c-axis direction. The mol­ecules are associated into a three-dimensional network supported by some weak C—H⋯O hydrogen bonds and C—H⋯π inter­actions.

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An improved crystal structure of the title compound, C30H30O8 (systematic name: 1,1′,6,6′,7,7′-hexa­hydroxy-5,5′-diisopropyl-3,3′-dimeth­yl[2,2′-bi­naphthalene]-8,8′-dicarbaldehyde), was determined based on modern CCD data. Compared to the previous structure [Talipov et al. (1985). Khim. Prirod. Soedin. (Chem. Nat. Prod.), 6, 20–24], geometrical precision has been improved (typical C—C bond-distance s.u. = 0.002 Å in the present structure compared to 0.005 Å in the previous structure) and the locations of several H atoms have been corrected. The gossypol mol­ecules are in the aldehyde tautomeric form and the dihedral angle between the naphthyl fragments is 80.42 (4)°. Four intra­molecular O—H⋯O hydrogen bonds are formed. In the crystal, inversion dimers with graph-set motif R 2 2(20) are formed by pairs of O—H⋯O hydrogen bonds; another pair of O—H⋯O hydrogen bonds with the same graph-set motif links the dimers into [001] chains. The packing of such chains in the crystal leads to the formation of channels (diameter = 5–8 Å) propagating in the [101] direction. The channels presumably contain highly disordered solvent mol­ecules; their contribution to the scattering was removed with the SQUEEZE [Spek (2015). Acta Cryst. C71, 9–18] routine in PLATON and the stated mol­ecular mass, density etc., do not take them into account.

Gossypol is secondary metabolite that play diverse role in plant adaptation to environment. Obtained from cottonseeds gossypol has valuable biological properties and forms an abundant number of clathrates with a large variety of compounds. One of the primary reasons why gossypol can form clathrates is its ability to organize extensive hydrogen bonding networks due to its hydroxyl and aldehyde functional groups. Less hundred clathrates as single crystals have been obtained and their crystallographic parameters have been determined. Solutions were prepared by adding 0.5 g of gossypol and 6.0 ml (6.3 g) of acetic acid, 4.0 ml (3 g) of acetone, 5.0 ml (4.5 g) of ethyl acetate, 2 ml (2.0 g) of 1,4-dioxane, 9.0 ml (13.4 g) of chloroform, 11.0 ml (9.6 g) of benzene to six small glasses vials at room temperature. The structures of 30 inclusion complexes have been solved by diffraction methods. This natural polyphenol forms stable clathrates with acetic acid, acetone, ethyl acetate, 1,4-dioxane, chloroform and benzene. This work describes investigation of gossypol clathrates by single-crystal diffraction and thermal analysis.

Enterprises producing phosphate fertilizers encounter a very serious problem associated with phosphogypsum piled up in huge amounts. To date, about 7 billion tons of phosphogypsum have been piled up all over the world with an average release of 180 million tons, and its utilization remains challenge. The process of phosphogypsum conversion of Kyzylkum phosphorite from JSC “Ammophos-Maxam” with soda ash of UE “Kungradsky soda plant” was studied in the work. The study was carried out in a wide range of concentration (10-20%) and stoichiometric norm (100-110%) of Na2CO3 at a temperature of 80°C and a time of 30 minutes. It was revealed that an increase in the concentration and stoichiometric norm of Na2CO3 leads to an increase in the degree of conversion of phosphogypsum into CaCO3 and Na2SO4 up to 97.07%. The following is optimal: the concentration of Na2CO3 is 20% and the stoichiometric norm is 105%, at which the degree of conversion is ⁓96%. As a result, the target product Na2SO4 was obtained with a purity of 94% and calcium carbonate - 96.25%. This solution allows producers of phosphate fertilizers to recycle phosphogypsum into products with high demand.