Evaluation of molybdate ester as a synergist for arylamine antioxidant in lubricants

An oil-soluble additive molybdate ester (ME) was synthesized. The antioxidation properties of p,p′-dioctyldiphenylamine (DODPA)- and ME-containing poly-α-olefin (PO)-derived lubricants were evaluated by differential scanning calorimetry (DSC) to measure and hot oil oxidation (HOO) tests. DSC test measures incipient oxidation temperature (IOT) and oxidation induction time (OIT) of the lubricant at high temperatures and the oxidation stability of oil viscosity increase is measured by HOO test. DSC test shows that IOT and OIT of DODPA-containing PO were improved significantly by ME addition. HOO test indicates that when combining with DODPA antioxidants, ME can also effectively reduce the increase in viscosity of the mineral oil 150 SN. These results suggest that the ME shows a good oxidative synergism with DODPA antioxidant. In addition, the changes occurring to DODPA in 150 SN oxidation with and without ME were observed by GC/MS analysis. The proposed mechanism of the inhibition involves a synergy between ME and DODPA.     

Evaluation of potassium trifluoroacetylacetonate as a synergist for arylamine antioxidant in synthetic lubricants

Differential scanning calorimetry (DSC) was employed to evaluate the performance of an ester lubricant containing potassium trifluoroacetylacetonate. In the isothermal DSC oxidation test, potassium trifluoroacetylacetonate is an effective synergist for arylamine antioxidants such as p, p'-dioctyldiphenylamine (DODPA). In combining with arylamine antioxidants, potassium trifluoroacetylacetonate can also effectively reduce the increase in viscosity and acid number of the ester oil in oxidation-corrosion tests. The electron paramagnetic resonance (EPR) results indicated that potassium trifluoroacetylacetonate can reduce the free radical content in the oxidised oil when arylamine antioxidants are present.     

Mixture of safflower oil and synthetic ester as a base stock for biodegradable lubricants

Biodegradable industrial lubricant applications are gaining popularity with growing environmental concern and stringent government regulations. Plant oils are major base stocks for eco‐friendly green lubricants. However, because of their poor oxidation stability, their applications are restricted to limited usages. Improvements of these plant oils can be made either by addition of functional additives or by chemical/genetic modifications. This paper evaluates the synergistic approach of phenolic and aminic antioxidants in safflower oil. Further, to enhance the oxidation properties of the plant oil, we incorporated and studied synthetic esters (SEs) for thermo‐oxidative stability by using rotating pressure vessel oxidation test and differential scanning calorimeter. The combination of phenolic and aminic antioxidants at a 2 : 1 ratio exhibited the best synergistic effect, when incorporated into a combination of plant oil and SE. In addition to thermo‐oxidative properties, the tribological properties of neat base stocks were also studied. A substitute of mineral oil‐based lubricants can be formulated cost effectively by using an appropriate mixture of plant oil and SE. Copyright © 2013 John Wiley & Sons, Ltd.     

PAH emissions of synthetic organic esters used as lubricants in a two-stroke engine

In this paper are presented some results of research into gaseous emissions from a two-stroke engine. These engines require a particular fuel consisting of a mixture of petrol and lubricating oil. In the research, a comparison was made between fuel mixtures containing mineral and synthetic base-stock lubricants, in order to check the chemical differences between exhaust emissions from the same motor run under the same conditions. This comparison was made because synthetic lubricants based on organic carboxylic esters, when compared to mineral ones, have some peculiar properties: a smaller combustion residue, better lubricating ability and better thermal stability. There are therefore good reasons to suppose that the lubricant fraction of fuel mixtures, after combustion, may cause gaseous emissions whose composition may vary according to the lubricant used.     

Modification of Wiley-Mclaren Tof Analyzers for Laser Desorption

ABSTRACT

Conversion of Wiley-McLaren type TOF instruments for laser desorption is described, including laser optics, timing circuitry, postacceleration detection for high mass and data acquisition. Results are shown to illustrate signal averaging capabilities, detection limits and high mass measurements.     

Hydrothermal synthesis of a lamellar zinc dimolybdate hydroxide with application as the anode for lithium-ion batteries

Abstract

A lamellar zinc dimolybdate hydroxide Zn₃Mo₂O₈(OH)₂ was prepared for the first time by a facile hydrothermal synthesis. The electrochemical properties of the lamellar Zn₃Mo₂O₈(OH)₂ as an anode material were investigated by cyclic voltammetry (CV), reversible capacity, cycling stability and rate capability for lithium ion batteries (LIB). The lamellar zinc dimolybdate hydroxide exhibits a reversible capacity of 404.6 mAh g^?1 at a current density of 100?mA g^?1 after 200 cycles. The reversible capacity of the lamellar Zn₃Mo₂O₈(OH)₂ remained at 60 mAh g^?1 even at a current density of 3000?mA g^?1. When the current density was returned to 100?mA g^?1, a discharge capacity of 380 mAh g^?1 was maintained after 200 discharge/charge cycles. The excellent electrochemical performance may be due to its unique lamellar structure, which buffers the volume change during the Li⁺ intercalation/de-intercalation and provides the electrode with convenient lithium ions and electron transport pathways. These results suggest the promising potential application of the lamellar zinc dimolybdate hydroxide in lithium-ion batteries.