A carbonate ester of an aliphatic triol or tetraol which can be defined with the following formula: ##STR1## wherein R.sub.1, R.sub.2, R' and p are as defined in the description, is used as a lubricating base with a low quantity of smoke for two-phase engines with internal combustion. Lubricating compositions are described which contain a carbonate ester (1) together with one or more products selected from solvents, bright stock, or other anti-seizing additives, plus normal additives.
A liquid composition comprising: (A) a monomeric, or essentially monomeric, diallyl-carbonate of a possibly halogenated diol containing aromatic groups; or a diallyl-ester of a halogenated aromatic bicarboxy acid; (B) a reactive monomer selected from diallyl orthophthalate, diallyl isophthalate, diallyl terephthalate, triallyl cyanurate and triallyl isocyanurate; (C) an oligomeric, or essentially oligomeric, diallyl-carbonate of diethylene glycol is polymerized under the action of a free-radical initiator, in order to yield optical articles having a high refractive index, low light dispersion, and with enhanced mechanical and color characteristics.