Comparison of Diesel Fuel Oxygenate Additives to the Composition-Explicit Distillation Curve Method. Part 1: Linear Compounds with One to Three Oxygens

Abstract

There is a great deal of interest in formulating oxygenated diesel fuels that produce low particulate emissions. The most common oxygenate additives for diesel fuels include the glycol ethers, glycol esters, alcohols, ethers, and ketones. It is important to characterize the mixture properties of diesel fuel with oxygenate additives, to assess the degree of departure of the oxygenated fuels from the base fuel. One of the most important properties to use for this purpose is the volatility, as expressed by the distillation curve. We have recently introduced several important improvements in the measurement of distillation curves of complex fluids. The modifications to the classical measurement provide (1) a composition-explicit data channel for each distillate fraction (for both qualitative, quantitative, and trace analysis), (2) temperature measurements that are true thermodynamic state points that can be modeled with an equation of state, (3) temperature, volume, and pressure measurements of low uncertainty suitable for equation of state development, (4) consistency with a century of historical data, (5) an assessment of the energy content of each distillate fraction, and (6) a corrosivity assessment of each distillate fraction. In this paper, we present measurements for dimethoxymethane, butyl methyl ether, 1,2-dimethoxyethane, 2-methoxyethyl acetate, 2-ethoxyethyl acetate, and diethylene glycol dimethyl ether. We find that the more volatile additives cause significant early departures from the distillation curves of diesel fuel, while the less volatile additives act more to displace the entire curve. We also note that the additive affects the curve shape and temperature profile even after being totally depleted, an observation made in earlier studies of oxygenate additive mixtures.

Selective Oxidation of Methanol to Dimethoxymethane at Low Temperatures through Size‐controlled VTiOx Nanoparticles

“…Dimethoxymethane (DMM), as a nontoxic and environmentally friendly methanol downstream product, is widely used in the cosmetics, pharmaceuticals, paints, and rubber industries. As a result of its high oxygen content and cetane number, it is also considered a promising diesel additive . Industrially, DMM is produced through a two‐stage process involving the oxidation of methanol to formaldehyde over silver or iron–molybdate catalysts followed by a condensation reaction in a methanol/formaldehyde mixture by using sulfuric acid or solid acidic catalysts, and in all, this is a high‐temperature, corrosive, complex, and costly process .…”

“…As ar esult of its high oxygen content and cetane number,i ti sa lso considered ap romising diesel additive. [1] Industrially,D MM is produced through at wostage processi nvolving the oxidation of methanol to formaldehyde over silver or iron-molybdate catalysts followed by ac ondensation reaction in am ethanol/formaldehyde mixture by using sulfuric acid or solid acidic catalysts, and in all, this is ah igh-temperature, corrosive, complex, and costly process. [2] Therefore, many efforts have been made to develop ad irect synthesis of DMM from the selectiveo xidation of methanol.…”

Application of the Advanced Distillation Curve Method to the Comparison of Diesel Fuel Oxygenates: 2,5,7,10-Tetraoxaundecane, 2,4,7,9-Tetraoxadecane, and Ethanol/Fatty Acid Methyl Ester Mixtures

“…These results are also similar to what we have reported for the oxygenates presented in previous work. 38–41 …”

“…This trend has been noted in in many of our earlier publications and it is particularly evident in mixtures where the oxygenate concentration used is relatively high. 38–41 This is an effect of the vapor liquid equilibrium that is established between the constituents of the fuel blends when one of the constituents (in this case the oxygenate) is more volatile than other constituents. The energy being applied is used to vaporize the most volatile component early in the distillation.…”

“…15, 17, 30–37 We have published several extensive studies on some of the most likely candidates from these categories. 22, 35, 38–43 Several of the additives described in these publications may be appropriate for the reformulation of diesel fuels, however, it remains necessary to identify novel oxygenating compounds with properties appropriate for fuel reformulation.…”