Chemicals and Food: An Account About Additives

Food additives are listed by functional category and discussed in terms of the scale of their use and relative risks in terms of long-term human toxicity. The greatest risks appear to lie with the antimicrobial preservative agents, and food colors (which serve only a cosmetic purpose); these and the synthetic sweeteners are discussed in relatively greater detail

3,5-Dibromobenzonitrile

Molecules of the title compound (I), C7H3Br2N, lie on a crystallographic mirror plane that bisects the benzene ring and the cyano group. In the crystal, no C[triple-bond]N...Br or Br...Br short contacts are observed. Head-to-tail C(7) chains form based on weak hydrogen bonding between the the para H atom and the cyano N atom. Although molecules of (I) pack differently than 3,5-difluorobenzonitrile, both compounds have similarly distorted benzene rings. For (I), the endocyclic bond angles are 121.16 (16)° and 117.78 (16)° about the ipso and para C atoms, respectively

2,6-Dibromo-4-nitrobenzonitrile

Molecules of the title compound, C7H2Br2N2O2, have C2v symmetry and each lie on a twofold axis that bisects the benzene ring and its nitro and cyano substituents. The cyano N atom is bisected by two CN...Br contacts, and the nitro O atoms participate in weak C—H...O hydrogen bonds. These interactions form a planar sheet structure that stacks about a glide plane. This stacking mode has not been previously reported with cyano-halo-derived sheets of this type