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DOI: 10.1039/C5RA13507A
ARTICLE TYPE
Capacity of Thiourea Schiff Base Ester as Multifunctional Additive:
Synthesis, Characterization and Performance Evaluation in Polyol
Raj K. Singh,a,* Aruna Kukrety,a Om P. Sharma,a Gananath D. Thakre,b Neeraj Atray,c Siddharth S.
Raya
5
Received (in XXX, XXX) Xth XXXXXXXXX 200X, Accepted Xth XXXXXXXXX 200X
First published on the web Xth XXXXXXXXX 200X
DOI: 10.1039/b000000x
A novel thiourea schiff base ester TSBE was synthesized following
novel additive shows excellent antiwear property and friction
10 two step reaction. At first, thiourea and salicylaldehyde were 55 reduction property similar to ZDDP, and exhibits better loadꢀ
reacted in ethanol to obtain thioura schiff base TSB. In the second
step, esterification of TSB was done with lauroyl chloride
catalyzed by 4ꢀ(dimethylamino)pyridine (DMAP) in N,Nꢀ
dimethylacetamide (DMAc) solvent to obtain final product TSBE.
carrying capacity than ZDDP. It has good anticorrosive
property and high thermal stability too.7 Two nonꢀphosphorus
and ashless multifunctional additives 1,3,4ꢀthiadiazoleꢀ2ꢀthione
derivatives, 5ꢀdodecyldithioꢀ3ꢀphenly1,3,4ꢀthiadiazoleꢀ2ꢀthione
15 The synthesized compounds were characterized using the CHN 60 and 5ꢀcetyldithioꢀ3ꢀphenylꢀ1,3,4ꢀthiadiazoleꢀ2ꢀthione were
analysis, FTꢀIR and NMR. The antioxidant property of this
additive was assessed via the universal oxidation test (IPꢀ306) and
rotary bomb oxidation test (ASTM D2272) while antifriction and
antiwear properties was evaluated in terms of average friction
synthesized and evaluated in rapeseed oil. The results indicated
that the additives possessed good thermal stabilities, corrosion
inhibiting abilities and excellent loadꢀcarrying capacities. Both
of them had good antiꢀwear and frictionꢀreducing property.8 A
20 coefficient and average wear scar diameter respectively by doing 65 novel borate ester derivative containing benzothiazolꢀ2ꢀyl and
the four ball test (ASTM D4172). Study revealed that TSBE had
good antioxidant property. Test carried out by four ball test
machine indicated that the additive TSBE could reduce the
friction to 45.6 % while wear to ~20 % when compared with the
25 pure polyol base oil.
disulfide group was synthesized and evaluated as
multifunctional additive in rapeseed oil. Results showed that it
possesses comprehensive tribological properties in loadꢀ
carrying, frictionꢀreducing, antiwear, corrosionꢀinhibiting, and
70 antioxidation, so probably had a chance to replace ZDDP
partially.9 A novel ashless and nonꢀphosphorus oilꢀsoluble
compound, 2,4,6ꢀtrioctylthioꢀ1,3,5ꢀtriazine was synthesized
and its performance as additive in a liquid paraffin was
evaluated using both; a fourꢀball wear tester and a fourꢀball EP
Zinc dialkyldithiophosphates (ZDDP) is considered to be the
most important and commercially successful antioxidant,
antiwear and anticorrosive multifunctional additive (MFA)
30 since its discovery in 1940.1 It is uncomparable in term of wide 75 wear test machine. The results showed that it behaved
usage. Its effectiveness made it the most preferred additive for
the formulated lubricants too for decades until now when the
environmental concerns and stringent laws goes against the use
of those compounds which have elements like Zn, P and S.2
extremely better as antiꢀwear and frictionꢀreducing additive.10
Three novel phosphorusꢀfree triazine derivatives, ZOO, ZOS
and ZDION were synthesized and evaluated as multifunctional
additives in rapeseed oil. The results suggested that all the
35 Apart from the environmental toxicity, few other shortcoming 80 synthesized compounds had good thermal stability, corrosion
are also associated with ZDDP that are forcing the
technologists to discover new MFA e.g. the catalytic converter
poisoning and the particulate emissions due to its ash content.3
Similarly, MFAs like over based metal sulfonate and mannich
inhibiting ability and excellent tribological behaviour.11 Two
ashless
dithiocarbamateꢀtriazine
and
nonꢀphosphorus
compounds,
hydroxylꢀcontaining
2,4,6ꢀtri[N,Nꢀdiꢀnꢀ
butyldithiocarmate(2’ꢀhydroxyl)ꢀpropionylthio]ꢀ1,3,5ꢀsꢀtriazine
2,4,6ꢀtri[N,Nꢀdiꢀiꢀoctyldithiocarmateꢀ(2’ꢀhydroxyl)ꢀ
40 adducts have similar environmental problems.4,5 So it would be 85 and
beneficial if we could replace some of the toxic elements from
the additive structure without sacrificing the performance.
Some efforts have been made to develop the MFAs having only
S but devoid of P and heavy metals. Most of these meaningful
propionylthio]ꢀ1,3,5ꢀsꢀtriazine were prepared and their
tribological behaviors as additives in rapeseed oil (RSO) were
evaluated using a fourꢀball tester. The results indicated that the
additives possessed high thermal stabilities, good loadꢀcarrying
45 efforts are restricted to sulfurized vegetable oils, heterocyclic 90 capacities, good antiꢀwear and friction reducing property.12 The
compounds and derivatives of natural compounds having
inherent disulfide groups e.g. sulfurized soybean, sunflower,
cottonseed, high erucic rapeseed, canola, limnanthes
(meadowfoam) and prime lard oils have been used as additives
tribological behaviors of laurylaminoꢀmethylthioꢀ1,3,5ꢀ
triazineꢀ2,4ꢀdithiol and diisooctylaminoꢀmethylthioꢀ1,3,5ꢀ
triazineꢀ2,4ꢀdithiol as additives in raped seed oil and diester
were evaluated using fourꢀball friction and wear tester. The
50 for metalworking and industrial oils.6 A heterocyclic derivative 95 results suggested that these synthesized compounds had
of
Sꢀ[2ꢀ(acetamido)
benzothiazolꢀ1ꢀyl]N,Nꢀdibutyl
excellent tribological behaviours.13
dithiocarbamate was synthesized and its performance as an
multifunctional additive in liquid paraffin was evaluated. The
Disulfides are also known to have loadꢀcarrying capacity e.g.
the tribological performance of binary additive blends with
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