Research On The Synthesis Of Diesel Dispersant

Diesel dispersant is a high effective material with a certain structure, polar groups of which have been found to have a strong absorption effect on the carbon deposition and sediments produced during combustion. This effect can loose the structure of these combustion products, transform them into small particles and clear them away. Therefore, diesel dispersant can serve to clean main part of engine as well as the diesel pathway. In general, diesel dispersant can be classified into two types: ash-based detergent and ash-free dispersant.High effective ash-based dispersants have been synthesized and selected. Besides, the synthesis process of lanthanum isooctoate were studied in detail. Furthermore, effectiveness of deposits in every part of engine and reduction in emission pollutants were evaluated by means of simulation bench test and diesel engine emission test, separately. Results of simulation bench test showed that addition of 300ppm lanthanum isooctoate reduced deposits in the relative lower temperature parts of engine by 74.8% and a colorful film could be observed, which was thought to prevent the formation of deposits; while results of diesel engine emission test indicated the addition of 300ppm lanthanum isooctoate reduced CO by 49.4% and NOx by 34.2%.Several kinds of ash-free dispersants have been synthesized including small molecule weight Mannich base products of 4 -tert-butyl-phenol and Mannich base oligomers based on Nonylphenol ethoxylates. In these products, Mannich base modification products of isopropylamine (M-2), octadecylamine (D-18), diethanolamine demonstrated clean effects to somewhat degree and similar or better effect can be achieved, compared with commercial dispersants. For Mannich base oligomers, three amines have been selected to react and nine dispersants were synthesized by modified with three organic acids (2-Ethylhexanoic acid,dodecanoic acid and Octadecanoic acid), separately. Simulation bench test results of representative products indicate that all the products have a clean effect to a certain degree, among which, OP-IV-12 presents the best effectiveness, reaching as high as 54.8%.Furthermore, effectiveness of compound diesel dispersants composed by ash-free dispersant and amine oligomers have also been investigated. The results suggest that the best compound dispersant is comprised by lanthanum isooctoate, D-18 and OP-IV-12 in the ratio of 1:2:1, and the clean effectiveness can reach 68.5%.