BRAKE LIQUID AND METHOD OF ITS PRODUCTION Russian patent published in 2009 - IPC C10M105/18 C10M105/78 C10N40/08 

FIELD: chemistry.

SUBSTANCE: there is known liquid containing a mix of polyethylene glycol monomethyl ethers, esters of boric acid and polyethylene glycol monomethyl ethers, anticorrosive and antioxidising additives. The mix of polyethylene glycol monomethyl ethers with the general formula CH₃(CH₂CH₂O)_nOH (1) where n=2-6 and with the average molecular weight of 170-180 units, features the following composition in wt %, i.e. 1-5 of diethylene glycol monomethyl ether, 60-75 of triethylene glycol monomethyl ether, 18-75 of tetraethylene glycol monomethyl ether, 3-7.5 pentaethylene glycol monomethyl ether, 0.6-1.5 of hexaethylene glycol monomethyl ether. The proposed brake liquid is produced by hydroxyethylation of hydroxyl compound in the presence of the alkaline agent, along with processing the hydroxyethyl product with boric acid, stripping of low-boiling components and introducing additives. The hydroxyethylation is performed till producing a reactionary mix with the mean molecular weight of 85 to 120 units. The aforesaid mix is subjected to rectification to produce a distillate and bottoms product of the formula (I) with the mean molecular weight of 170 to 180 units to be processed with boric acid in the amount of 5-7 wt %. Water is stripped off from the resulted borated product in the presence of an antioxidising additive and, thereafter, an anticorrosive additive is added. A mix of methanol and recycled distillate at the ratio of 0.05-0.15:1 is used as a hydroxyl compound. After rectification, the distillate is subjected to recycling to the hydroxyethylation stage.

EFFECT: higher liquid boiling and lower viscosity at negative temperatures.

4 cl, 3 tbl, 3 ex