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PROPERTIES OF BIODIESEL
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Additive: Material Added In Small Amounts To Finished Fuel
Products To Improve Certain Properties Or Characteristics.
Antioxidant: Substance That Inhibits Reactions Promoted By
Oxygen
Aromatic Compound: A Hydrocarbon Based On A Six-Carbon
Benzenoid Ring
Biodiesel: Methyl Esters Of Fatty Acids Meeting The Requirements
Of Astm Specification D6751.
Biodegradable: Capable Of Being Broken Down By The Action Of
Microorganisms
Boiling Range: The Spread Of Temperature Over Which A Fuel, Or
Other Mixture Of Compounds, Distills.
Cetane Index: An Approximation Of Cetane Number Based On An
Empirical Relationship With Density And Volatility Parameters
Such As The Mid-Boiling Point. This Approximation Is Not Valid For
Biodiesel Or Biodiesel Blends.
Cetane Number: A Measure Of The Ignition Quality Of Diesel Fuel
Based On Ignition Delay In An Engine. The Higher The Cetane
Number, The Shorter The Ignition Delay And The Better The
Ignition Quality.
Chelating Compound: A Fuel Additive That Deactivates The
Catalytic Oxidizing Action Of Dissolved Metals, Notably Copper,
On Fuels During Storage.
Ci: Compression Ignition, I.E. A Diesel Engine
Cloud Point: The Temperature At Which A Sample Of A Fuel Just
Shows A Cloud Or Haze Of Wax (Or In The Case Of Biodiesel,
Methyl Ester) Crystals When It Is Cooled Under Standard Test
Conditions, As Defined In Astm D2500.
Detergent: A Fuel Detergent Is An Oil-Soluble Surfactant Additive
That Maintains The Cleanliness Of Engine Parts By Solubilizing
Deposits Or Materials Likely To Deposit In The Engine Fuel
System.
Dispersant: A Surfactant Additive Designed To Hold Particulate
Matter Dispersed In A Liquid.
Elastomer: Synthetic Rubber-Type Material Frequently Used In
Vehicle Fuel Systems (But Not Necessarily Natural Or Synthetic
Rubber, May Also Apply To Other Polymers).
Energy Content: The Heat Produced On Combustion Of A
Specified Volume Or Mass Of Fuel, Also Known As Heating Value
Or Heat Of Combustion.
EPAct: Energy Policy Act of 1992. Title III provides incentives to
promote the use of alternative fuel vehicles in transportation.
fatty acid methyl esters (FAME): Mono alkyl ester of long-chain
fatty acids from naturally occurring vegetable oil, animal fats, and
recycled greases.
fatty acid: any of the saturated or unsaturated monocarboxylic
acids that occur naturally in the form of triglycerides (or mono or
diglycerides) or as free fatty acids in fats and fatty oils.
flash point: the lowest temperature at which vapors from a fuel
will ignite on application of a small flame under standard test
conditions.
Free fatty acids: any saturated or unsaturated monocarboxylic
acids that occur naturally fats, oils or greases but are not
attached to glycerol backbones. These can lead to high acid fuels
and require special processes technology to convert into
biodiesel.
Hydrocarbon (HC): a compound composed of hydrogen and
carbon. Hydrocarbons can refer to fuel components and to
unburned or poorly combusted components in vehicle exhaust.
kerosene: a refined petroleum distillate of which different grades
are used as lamp oil, as heating oil, blended into diesel fuel, and
as fuel for aviation turbine engines.
lubricity: the ability of a fuel to lubricate.
microbial contamination: containing deposits or suspended matter
formed by microbial degradation of the fuel.
multifunctional additive: an additive or blend of additives with
more than one function.
OEM: original engine manufacturer.
Oxidation: Loosely, The Chemical Combination Of Oxygen To A
Molecule.
Oxidative Stability: The Ability Of A Fuel To Resist Oxidation
During Storage Or Use.
Oxygenate: A Fuel Component That Contains Oxygen; I.E.,
Biodiesel Or Ethanol.
Particulate Matter (Pm): The Solid Or Semi-Solid Compounds Of
Unburned Fuel That Are Emitted From Engines.
Polycyclic Aromatic Hydrocarbons (Pah): Aromatic Compounds
With More Than One Benzenoid Ring (Pah). Also, Npah For Nitro-
Polyaromatic Compounds.
Polyunsaturated Fatty Acids: Fatty Acids With More Than One
Double Bond.
Pour Point: The Lowest Temperature At Which A Fuel Will Just Flow
When Tested Under Standard Conditions As Defined In Astm D97.
Saturation: Or Saturated Compound. A Paraffinic Hydrocarbon Or
Fatty Acid, I.E. With Only Single Bonds And No Double Or Triple
Bonds.
Solvency: The Quality Or State Of Being A Solvent.
Specific Gravity: The Ratio Of The Density Of A Substance To The
Density Of Water.
Splash Blending: The Fuels To Be Blended Are Delivered
Separately Into A Tank Truck
Stratification: To Separate Into Layers.
Storage Stability: The Ability Of A Fuel To Resist Deterioration On
Storage Due To Oxidation.
Torque: A Force That Produces Rotation.
Viscosity: A Measure Of The Resistance To Flow Of A Liquid.
A chemical property is any of a material's properties that
becomes evident during a chemical reaction; that is, any quality
that can be established only by changing a substance's chemical
identity.[1] Simply speaking, chemical properties cannot be
determined just by viewing or touching the substance; the
substance's internal structure must be affected for its chemical
properties to be investigated. However a catalytic property would
also be a chemical property.
The pour point of a liquid is the temperature at which it becomes
semi solid and loses its flow characteristics. In crude oil a high
pour point is generally associated with a highparaffin,or kerosene
content, typically found in crude deriving from a larger proportion
of plant material. That type of crude oil is mainly derived from
a kerogen Type II.
Gel point is the temperature at
which diesel or biodiesel fuel freezes solid and can no longer flow
by gravity or be pumped through fuel lines. This phenomenon
happens when a fuel reaches a low enough temperature whereby
enough wax crystals have formed to prevent any movement in
the oil. For #2 diesel this is usually around 17.5 °F (−8.1 °C).
For the fuel to become pumpable again, it needs to be brought
above the gel point temperature to the Ungel point, which is
typically near its pour point. However, most of the waxes will still
remain in solid form and the fuel has to be warmed up further
until its Remix temperature in order to completely remelt and
redissolve the waxes.
Anti-gel additives are therefore commonly added to diesel or
biodiesels where cold temperature is expected. They act to
reduce the formation of wax crystals in the fuel, thereby lowering
the pour point and the gel point of the fuel. Anti-gel additives may
not necessarily affect the cloud point.
The cloud point of a fluid is the temperature at which dissolved
solids are no longer completely soluble, precipitating as a second
phase giving the fluid a cloudy appearance. This term is relevant
to several applications with different consequences.
In the petroleum industry, cloud point refers to the temperature
below which wax in diesel or biowax in biodiesels form a cloudy
appearance. The presence of solidified waxes thickens the oil and
clogs fuel filters and injectors in engines. The wax also
accumulates on cold surfaces (e.g. pipeline or heat
exchanger fouling) and forms an emulsion with water. Therefore,
cloud point indicates the tendency of the oil to plug filters or small
orifices at cold operating temperatures
The chemical composition of a mixture can be defined as the
distribution of the single substances that constitute the mixture
(called "components"). In other words, it is defined giving
the concentration of each component.
Because there are different ways to define the concentration of a
component, as a consequence there are also different ways to
define the composition of a mixture. For example it can be
expressed as molar fraction, volume fraction, mass
fraction, molality, molarity or normality.
Molarity" redirects here. It is not to be confused with Molality.
In chemistry, the molar concentration, is defined as
the amount of a constituent (usually measured in moles –
hence the name) divided by the volume of the mixture :[1]
It is also called molarity, amount-of-substance
concentration, amount concentration, substance
concentration, or simply concentration. Whereas mole
fraction is a ratio of moles to moles, molar concentration is a
ratio of moles to volume. The volume in the
definition refers to the volume of the solution, not the
volume of the solvent. One litre of a solution usually contains
either slightly more or slightly less than 1 liter of solvent
because the process of dissolution causes volume of liquid to
increase or decrease (discussed further at volume fraction).
In chemistry, the molality, b (or m), of a solution is defined as
the amount of substance (in mol) of solute, , divided by
the mass (in kg) of the solvent, (not the mass of the
solution):[1]
The enthalpy of solution, enthalpy of dissolution, or heat of
solution is the enthalpy change associated with the dissolution of
a substance in a solvent at constant pressure resulting in infinite
dilution.
The enthalpy of solution is most often expressed in kJ/mol at
constant temperature. The energy change can be regarded as
being made of three parts, the endothermic breaking of bonds
within the solute and within the solvent, and the formation of
attractions between the solute and the solvent. An ideal
solution has an enthalpy of solution of zero. For a non-ideal
solution it is an excess molar quantity.
The enthalpy of mixing (also called heat of mixing) is
the heat that is taken up or released upon mixing of two (non-
reacting) chemical substances. When the enthalpy of mixing is
positive, mixing is endothermic while negative enthalpy of mixing
signifies exothermic mixing. In ideal mixtures the enthalpy of
mixing is null. In non-ideal mixtures thethermodynamic activity of
each component is different from its concentration by multiplying
with the activity coefficient.
Chemical properties:
Enthalpy of reaction, defined as the enthalpy change observed
in a constituent of a thermodynamic system when one mole of
substance reacts completely.
Enthalpy of formation, defined as the enthalpy change
observed in a constituent of a thermodynamic system when
one mole of a compound is formed from its elementary
antecedents.
Enthalpy of combustion, defined as the enthalpy change
observed in a constituent of a thermodynamic system when
one mole of a substance burns completely with oxygen.
Enthalpy of hydrogenation, defined as the enthalpy change
observed in a constituent of a thermodynamic system when
one mole of an unsaturated compound reacts completely with
an excess of hydrogen to form a saturated compound.
Enthalpy of atomization, defined as the enthalpy change
required to atomize one mole of compound completely.
Enthalpy of neutralization, defined as the enthalpy change
observed in a constituent of a thermodynamic system when
one mole of water is formed when an acid and a base react.
Standard Enthalpy of solution, defined as the enthalpy change
observed in a constituent of a thermodynamic system when
one mole of a solute is dissolved completely in an excess of
solvent, so that the solution is at infinite dilution.
Standard enthalpy of Denaturation (biochemistry), defined as
the enthalpy change required to denature one mole of
compound.
Enthalpy of hydration, defined as the enthalpy change
observed when one mole of gaseous ions are completely
dissolved in water forming one mole of aqueous ions.
Physical properties:
Enthalpy of fusion, defined as the enthalpy change required to
completely change the state of one mole of substance between
solid and liquid states.
Enthalpy of vaporization, defined as the enthalpy change
required to completely change the state of one mole of
substance between liquid and gaseous states.
Enthalpy of sublimation, defined as the enthalpy change
required to completely change the state of one mole of
substance between solid and gaseous states.
Lattice enthalpy, defined as the energy required to separate
one mole of an ionic compound into separated gaseous ions to
an infinite distance apart (meaning no force of attraction).
Enthalpy of mixing, defined as the enthalpy change upon
mixing of two (non-reacting) chemical substances.
Enthalpy is a defined thermodynamic potential, designated by
the letter "H", that consists of the internal energy of the system
(U) plus the product of pressure (p) and volume (V) of the system:[1]
Since enthalpy, H, consists of internal energy, U, plus the
product of pressure (p) and the volume (V) of the system,
which are all functions of the state of the thermodynamic
system, enthalpy is a state function.
Freezing-point depression describes the process in which
adding a solute to a solvent decreases the freezing point of the
solvent.
Examples include salt in water, alcohol in water, or the mixing of
two solids such as impurities in a finely powdered drug. In the last
case, the added compound is the solute, and the original solid is
thought of as the solvent. The resulting solution or solid-solid
mixture has a lower freezing point than the pure solvent or solid
did. This phenomenon is what causes sea water, (a mixture of salt
(and other things) in water) to remain liquid at temperatures
below 0 °C (32 °F), the freezing point of pure water.
In chemistry, colligative properties are properties
of solutions that depend upon the ratio of the number of solute
particles to the number of solvent molecules in a solution, and
not on the type of chemical species present.[1] This number
ratio can be related to the various units for concentration of
solutions. Here we shall only consider those properties which
result because of the dissolution of nonvolatile solute in a
volatile liquid solvent.[2] They are independent of the nature of
the solute particles, and are due essentially to the dilution of
the solvent by the solute. The word colligative is derived from
the Latin colligatus meaning bound together.[3]
Solubility equilibrium is a type of dynamic equilibrium. It exists
when a chemical compound in the solid state is in chemical
equilibrium with a solution of that compound. The solid may
dissolve unchanged, with dissociation or with chemical reaction
with another constituent of the solvent, such as acid or alkali.
Each type of equilibrium is characterized by a temperature-
dependent equilibrium constant. Solubility equilibria are
important in pharmaceutical, environmental and many other
scenarios.
A solubility equilibrium exists when a chemical compound in the
solid state is in chemical equilibrium with a solution of that
compound. The equilibrium is an example of dynamic
equilibrium in that some individual molecules migrate between
the solid and solution phases such that the rates
of dissolution and precipitation are equal to one another. When
equilibrium is established, the solution is said to be saturated.
The concentration of the solute in a saturated solution is known
as the solubility. Units of solubility may be molar (mol dm−3) or
expressed as mass per unit volume, such as μg ml−1. Solubility is
temperature dependent. A solution containing a higher
concentration of solute than the solubility is said to
be supersaturated. A supersaturated solution may be induced to
come to equilibrium by the addition of a "seed" which may be a
tiny crystal of the solute, or a tiny solid particle, which initiates
precipitation.
Molar solubility is the number of moles of a substance (the
solute) that can be dissolved per liter of solution before the
solution becomes saturated. It can be calculated from a
substance's solubility product constant (Ksp) and stoichiometry.
The units are mol/L, sometimes written as M.
Diesel engines can be run with a lean burn air-to-fuel ratio
(overstoichiometric ratio), to ensure the full combustion of soot
and to prevent the exhaust of unburnt fuel. The excess of oxygen
necessarily leads to generation of nitrogen oxides (NOx), which
are harmful pollutants, from the nitrogen in the air. Selective
catalytic reduction is used to reduce the amount of NOx released
into the atmosphere. Diesel exhaust fluid (from a separate DEF
tank) is injected into the exhaust pipeline, the aqueous urea
vaporizes and decomposes to form ammonia and carbon dioxide.
Within the SCR catalyst, the NOx are catalytically reduced by the
ammonia (NH3) into water (H2O) and nitrogen (N2), which are both
harmless; and these are then released through the exhaust.[3]
Diesel Exhaust Fluid (DEF) is an emissions control liquid required
by modern diesel engines. It is injected into the exhaust stream.
DEF is never added to diesel fuel. It is a non-hazardous solution of
32.5% urea in 67.5% de-ionized water. DEF is clear and colorless,
and looks exactly like water. It has a slight smell of ammonia,
similar to some home cleaning agents. DEF is used in by Selective
Catalytic Reduction (SCR) technology to remove harmful NOx
emissions from diesel engines.
In January 2010, the U.S. Environmental Protection Agency (EPA)
brought in new emissions standards requiring medium- and
heavy-duty vehicles to significantly reduce engine emissions,
particularly NOx and particulate matter (PM). Vehicle
manufacturers use SCR to meet these standards. DEF is sprayed
into the exhaust, breaking down NOx gases into nitrogen and
water using an advanced catalyst system. As a result most new
diesel trucks, pickups, SUVs, and vans are now fitted with SCR
technology and have a DEF tank that must be regularly refilled.
EPA set the emissions standards to improve air quality. NOx and
PM emissions are associated with a wide range of health problems
including respiratory and cardiovascular diseases, aggravation of
asthma, acute respiratory symptoms, chronic bronchitis and
decreased lung function. The EPA estimates that the emission
standards will prevent 8,300 premature deaths, more than 9,500
hospitalizations and 1.5 million work days lost due to illness,
saving approximately $70.3 billion by 2030. But yet there is still
the cost of buying the Diesel Exhaust Fluid.
SCR is a so-called "aftertreatment" technology, which means that
it destroys harmful emissions after combustion. This gives
manufacturers greater scope to tune engines to improve fuel
efficiency and increase power. Owners of SCR vehicles enjoy
greater reliability and longer oil change intervals, which add up to
impressive operating cost savings over the life of the vehicle
A diluent (also referred to as a filler, dilutant or thinner) is
a diluting agent. Certain fluids are too viscous to be pumped
easily or too dense to flow from one particular point to the other.
This can be problematic, because it might not be economically
feasible to transport such fluids in this state. To ease this
restricted movement, diluents are added. This decreases the
viscosity of the fluids, thereby also decreasing the
pumping/transportation costs.
One industrial application is the transport of crude oil via
pipelines. Heavy crude oil/bitumen are fluids with high viscosity,
especially at low temperatures. The addition of a diluent enables
the diluted fluid (dilbit in the case of bitumen) to meet pipeline
specifications in order for it to be efficiently transported. Typical
diluent in this case is naphtha orcondensate.
A dispersion is a system in which particles are dispersed in a
continuous phase of a different composition (or state). See
also emulsion. A dispersion is classified in a number of different
ways, including how large the particles are in relation to the
particles of the continuous phase, whether or
not precipitation occurs, and the presence of Brownian motion.
IUPAC definition
Material comprising more than one phase where at least one
of the phases consists of finely divided phase domains, often in
the
colloidal size range, dispersed throughout a continuous phase.[1]
Note 1: Modification of definition in ref.[2]
There are three main types of dispersions:
Coarse dispersion (Suspension)
Colloid
Solution
The enthalpy of solution, enthalpy of dissolution, or heat of
solution is the enthalpy change associated with the dissolution of
a substance in a solvent at constant pressure resulting in infinite
dilution.
The enthalpy of solution is most often expressed in kJ/mol at
constant temperature. The energy change can be regarded as
being made of three parts, the endothermic breaking of bonds
within the solute and within the solvent, and the formation of
attractions between the solute and the solvent. An ideal
solution has an enthalpy of solution of zero. For a non-ideal
solution it is an excess molar quantity.
In chemistry, a solution is a homogeneous mixture composed of
only one phase. In such a mixture, a solute is a
substance dissolved in another substance, known as a solvent.
The solution more or less takes on the characteristics of the
solvent including its phase, and the solvent is commonly the
major fraction of the mixture. The concentration of a solute in a
solution is a measure of how much of that solute is dissolved in
the solvent.
The ability of one compound to dissolve in another compound is
called solubility. When a liquid can completely dissolve in another
liquid the two liquids are miscible. Two substances that can never
mix to form a solution are called immiscible.
All solutions have a positive entropy of mixing. The interactions
between different molecules or ions may be energetically favored
or not. If interactions are unfavorable, then thefree
energy decreases with increasing solute concentration. At some
point the energy loss outweighs the entropy gain, and no more
solute particles can be dissolved; the solution is said to
be saturated. However, the point at which a solution can become
saturated can change significantly with different environmental
factors, such as temperature, pressure, and contamination. For
some solute-solvent combinations a supersaturated solution can
be prepared by raising the solubility (for example by increasing
the temperature) to dissolve more solute, and then lowering it
(for example by cooling).
Usually, the greater the temperature of the solvent, the more of a
given solid solute it can dissolve. However, most gases and some
compounds exhibit solubilities that decrease with increased
temperature. Such behavior is a result of an exothermic enthalpy
of solution. Some surfactants exhibit this behaviour. The solubility
of liquids in liquids is generally less temperature-sensitive than
that of solids or gases.
The fire point of a fuel is the temperature at which the vapour
produced by that given fuel will continue to burn for at least 5
seconds after ignition by an open flame. At the flash point, a
lower temperature, a substance will ignite briefly, but vapor might
not be produced at a rate to sustain the fire. Most tables of
material properties will only list material flash points, but in
general the fire points can be assumed to be about 10 °C higher
than the flash points. However, this is no substitute for testing if
the fire point is safety critical. It is done by open cup apparatus.
The autoignition temperature or kindling point of a
substance is the lowest temperature at which it
will spontaneously ignite in a normal atmosphere without an
external source of ignition, such as a flame or spark. This
temperature is required to supply the activation energy needed
for combustion. The temperature at which a chemical will ignite
decreases as the pressure or oxygen concentration increases. It is
usually applied to a combustible fuel mixture.
Autoignition temperatures of liquid chemicals are typically
measured using a 500 mL flask placed in a temperature
controlled oven in accordance with the procedure described
inASTM E659.[1]
Destructive distillation is the chemical process involving
the decomposition of feedstock by heating to a high temperature;
the term generally applies to processing of organicmaterial in the
absence of air or in the presence of limited amounts of oxygen or
other reagents, catalysts, or solvents, such as steam or phenols.
It is an application of pyrolysis. The process breaks up
or 'cracks' large molecules. Coke, coal gas, gas carbon, coal tar,
Buckministerfullerene, ammonia liquor, and "coal oil" historically,
are examples of commercial products of the destructive
distillation of coal.
Dry distillation is the heating of solid materials to
produce gaseous products (which may condense into liquids or
solids). The method may not involve pyrolysis/thermolysis. The
products are condensed and collected. This method usually
requires higher temperatures than classical distillation. The
method has been used to obtain liquid fuels from coaland wood. It
can also be used to break down mineral salts such
as sulfates through thermolysis, in this case producing sulfur
dioxide/sulfur trioxide gas which can be dissolved in water to
obtain sulfuric acid. By this method sulfuric acid was first
identified and artificially produced.
Thermal decomposition, or thermolysis, is a chemical
decomposition caused by heat. The decomposition
temperature of a substance is the temperature at which the
substance chemically decomposes.
The reaction is usually endothermic as heat is required to
break chemical bonds in the compound undergoing
decomposition. If decomposition is sufficiently exothermic,
apositive feedback loop is created producing thermal
runaway and possibly an explosion.
In petroleum geology and chemistry, cracking is the process
whereby complex organic molecules such as kerogens or
heavy hydrocarbons are broken down into simpler molecules such
as light hydrocarbons, by the breaking of carbon-carbon bonds in
the precursors. The rate of cracking and the end products are
strongly dependent on thetemperature and presence of catalysts.
Cracking is the breakdown of a large alkane into smaller, more
useful alkanes and alkenes. Simply put, hydrocarbon cracking is
the process of breaking a long-chain of hydrocarbons into short
ones.
An oxidizing agent (also oxidant, oxidizer or oxidiser) is the
element or compound in an oxidation-reduction (redox) reaction
that accepts an electronfrom another species. Because the
oxidizing agent is gaining electrons (and is thus often called
an electron acceptor), it is said to have been reduced.
The oxidizing agent itself is reduced, as it is taking electrons onto
itself, but the reactant is oxidized by having its electrons taken
away by the oxidizing agent. Oxygen is the prime
(and eponymous) example among the varied types of oxidizing
agents, but oxidisers (e.g., chlorine trifluoride) do not necessarily
donate or contain oxygen.
Fusibility is the ease with which a material will melt. Materials
such as solder require a low melting point so that when heat is
applied to a joint, the solder will melt before the materials being
soldered melt, i.e. high fusibility. On the other hand, firebricks
used for furnace linings only melt at very high temperatures and
so have low fusibility. Materials that only melt at very high
temperatures are called refractorymaterials.
Heat capacity, or thermal capacity, is a measurable physical
quantity equal to the ratio of the heat added to (or subtracted
from) an object to the resulting temperature change.[1] The SI unit
of heat capacity is joule per kelvin, and the dimensional form is
M1L2T−2Θ−1.
A pyrophoric substance (from Greek πυροφόρος, pyrophoros,
"fire-bearing") ignites spontaneously in air at or below 55°C
(130°F).[1] Examples are iron sulfide and many
reactive metals including uranium, when powdered or thinly
sliced. Pyrophoric materials are often water-reactive as well and
will ignite when they contact water or humid air. They can be
handled safely in atmospheres of argon or (with a few
exceptions) nitrogen. Most pyrophoric fires should be
extinguished with a Class D fire extinguisher for burning metals.
Organic chemistry is a chemistry subdiscipline involving
the scientific study of the structure, properties, and reactions
of organic compounds andorganic materials, i.e., matter in its
various forms that contain carbon atoms.[1] Study of structure
includes using spectroscopy (e.g., NMR), mass spectrometry, and
other physical and chemical methods to determine the chemical
composition and constitution of organic compounds and
materials. Study of properties includes both physical
properties and chemical properties, and uses similar methods as
well as methods to evaluate chemical reactivity, with the aim to
understand the behavior of the organic matter in its pure form
(when possible), but also in solutions, mixtures, and fabricated
forms. The study of organic reactions includes probing their scope
through use in preparation of target compounds (e.g., natural
products, drugs,polymers, etc.) by chemical synthesis, as well as
the focused study of the reactivities of individual organic
molecules, both in the laboratory and via theoretical (in silico)
study.
Catalysis is the increase in the rate of a chemical reaction due to
the participation of an additional substance called a catalyst.[1] With a catalyst, reactions occur faster and with less energy.
Because catalysts are not consumed, they are recycled. Often
only tiny amounts are required.
Cold filter plugging point (CFPP) is the lowest temperature,
expressed in degrees Celsius (°C), at which a given volume
of diesel type of fuel still passes through a
standardized filtration device in a specified time when cooled
under certain conditions. This test gives an estimate for the
lowest temperature that a fuel will give trouble free flow in certain
fuel systems. This is important as in cold temperate countries, a
high cold filter plugging point will clog up vehicle engines more
easily.
In cooking, the smoke point of an oil or fat is the temperature at
which, under defined conditions, enough volatile compounds
emerge from the oil that a bluish smoke becomes clearly visible.
At this temperature, volatile compounds, such as water, free fatty
acids, and short-chain degradation products of oxidation come up
from the oil. The smoke point is the temperature at which the oil
is decomposed and where possibly toxicological relevant
compounds are formed.
In chemistry, the standard molar entropy is
the entropy content of one mole of substance, under standard
conditions (not standard temperature and pressure STP).
The standard molar entropy is usually given the symbol S°, and as
units of joules per mole kelvin (J mol−1 K−1). Unlike standard
enthalpies of formation, the value of S° is an absolute. That is, an
element in its standard state has a nonzero value of S° at room
temperature. The entropy of a pure crystalline structure can be 0
J mol−1 K−1 only at 0 K, according to the third law of
thermodynamics. However, this presupposes that the material
forms a 'perfect crystal' without any frozen in entropy (defects,
dislocations), which is never completely true because crystals
always grow at a finite temperature. This residual entropy is often
quite negligible.
In thermodynamics, entropy (usual symbol S) is a measure of the
number of specific ways in which a thermodynamic system may
be arranged, commonly understood as a measure of disorder.
According to the second law of thermodynamics the entropy of
anisolated system never decreases; such a system will
spontaneously evolve toward thermodynamic equilibrium, the
configuration withmaximum entropy. Systems that are not
isolated may decrease in entropy, provided they increase the
entropy of their environment by at least that same amount. Since
entropy is a state function, the change in the entropy of a system
is the same for any process that goes from a given initial state to
a given final state, whether the process
is reversible or irreversible. However irreversible processes
increase the combined entropy of the system and its
environment.
Lower flammability limit (LFL),[1] usually expressed in volume
per cent, is the lower end of the concentration range over which a
flammable mixture of gas or vapour in air can ignite at a given
temperature and pressure. The flammability range is delineated
by the upper and lower flammability limits. Outside this range of
air/vapor mixtures, the mixture will not ignite (unless the
temperature and pressure are increased). The LFL decreases with
increasing temperature; thus, a mixture that is below its LFL at a
given temperature may ignite if heated sufficiently. For liquids,
the LFL is typically close to the saturated vapor concentration at
the flash point, however, due to differences in the liquid
properties, the relationship of LFL to flash point (which is also
dependent on the test apparatus) is not fixed and some spread in
the data usually exists.
Minimum ignition energy (MIE) is the minimum amount of
energy required to ignite a combustible vapor, gas or dust cloud,
for example by means of an electrostatic discharge. Ignition of a
fuel/air mixture is possible only when the rate of liberation of heat
near the ignition zone is greater than the heat loss by conduction.
Heat loss due to radiation is not considered, as it is assumed to be
negligible, and the ignition process is assumed to be steady and
one-dimensional[clarification needed]. MIE is measured in joules.
flammability is how easily something will burn or ignite,
causing fire or combustion. The degree of difficulty required to
cause the combustion of a substance is quantified through fire
testing. Internationally, a variety of test protocols exist to quantify
flammability. The ratings achieved are used in building codes,
insurance requirements, fire codes and other regulations
governing the use of building materials as well as the storage and
handling of highly flammable substances inside and outside of
structures and in surface and air transportation. For instance,
changing an occupancy by altering the flammability of the
contents requires the owner of a building to apply for a building
permit to make sure that the overall fire protection design basis
of the facility can take the change into account.
Miscibility / m ɪsɨ ̍ bɪlɨt i / is the property of substances to mix in all
proportions, forming a homogeneous solution. The term is most
often applied to liquids, but applies also to solids and
gases. Water and ethanol, for example, are miscible because they
mix in all proportions.[1]
By contrast, substances are said to be immiscible if a significant
proportion does not form a solution. Otherwise, the substances
are considered miscible. For example, butanone is significantly
soluble in water, but these two solvents are not miscible because
they are not soluble in all proportions.
An emulsion is a mixture of two or more liquids that are
normally immiscible (nonmixable or unblendable). Emulsions are
part of a more general class of two-phase systems
of matter called colloids. Although the
terms colloid and emulsion are sometimes used
interchangeably, emulsionshould be used when both the
dispersed and the continuous phase are liquids. In an emulsion,
one liquid (the dispersed phase) is dispersed in the other (the
continuous phase). Examples of emulsions
include vinaigrettes, milk, mayonnaise, and some cutting
fluids for metal working.
A multiphasic liquid is a mixture consisting of more than
two immiscible liquid phases. Biphasic mixtures consisting of two
immiscible phases are very common and usually consist of
an organic solvent and an aqueous phase ("oil and water").
Multiphasic liquids can be used for selective liquid-liquid
extractions or for decorative purposes, e.g. in cosmetics.
While it is possible to get multilayered phases by
layering nonpolar and aqueous phases of decreasing densities on
top of each other, these phases will not separate after mixing like
true multiphasic liquids.
A vapor (American English spelling) or vapour (British) is a
substance in the gas phase at a temperature lower than its critical
point,[1]which means that the vapor can be condensed to
a liquid by increasing its pressure without reducing the
temperature.
For example, water has a critical temperature of 374 °C (647 K),
which is the highest temperature at which liquid water can exist.
In theatmosphere at ordinary temperatures, therefore, gaseous
water (known as water vapor) will condense to liquid if its partial
pressure is increased sufficiently.
A vapor may co-exist with a liquid (or solid). When this is true, the
two phases will be in equilibrium, and the gas partial pressure will
equal the equilibrium vapor pressure of the liquid (or solid).[1]
In thermodynamics, the triple point of a substance is
the temperature and pressure at which the
three phases (gas, liquid, and solid) of that substance coexist
in thermodynamic equilibrium.[1] For example, the triple point
of mercury occurs at a temperature of −38.8344 °C and a
pressure of 0.2 m Pa .
In addition to the triple point between solid, liquid, and gas, there
can be triple points involving more than one solid phase, for
substances with multiple polymorphs. Helium-4 is a special case
that presents a triple point involving two different fluid phases
True vapor pressure (TVP) is a common measure of the
volatility of petroleum distillate fuels. It is defined as the
equilibrium partial pressure exerted by a volatile organic liquid as
a function of temperature as determined by the test method
ASTM D 2879.[1]
The true vapor pressure (TVP) at 100 °F differs slightly from
the Reid vapor pressure (RVP) (per definition also at 100 °F), as it
excludes dissolved fixed gases such as air.
Vapor pressure or equilibrium vapor pressure is defined as
the pressure exerted by a vapor in thermodynamic
equilibrium with itscondensed phases (solid or liquid) at a given
temperature in a closed system. The equilibrium vapor pressure is
an indication of a liquid'sevaporation rate. It relates to the
tendency of particles to escape from the liquid (or a solid). A
substance with a high vapor pressure at normal temperatures is
often referred to as volatile.
A crude oil assay is essentially the chemical evaluation of crude
oil feedstocks by petroleum testing laboratories. Each crude oil
type has unique molecular, chemicalcharacteristics. No crude oil
type is identical and there are crucial differences in crude oil
quality. The results of crude oil assay testing provide extensive
detailed hydrocarbonanalysis data for refiners, oil traders and
producers. Assay data help refineries determine if a crude oil
feedstock is compatible for a particular petroleum refinery or if
the crude oil could cause yield, quality, production, environmental
and other problems. "Crude Oil Assay". Intertek Worldwide.
Retrieved 4/2/14.
The assay can be an inspection assay or comprehensive assay.
Testing can include crude oil characterization of whole crude oils
and the various boiling range fractions produced from physical or
simulated distillation by various procedures. Information obtained
from the petroleum assay is used for detailed refinery engineering
and client marketing purposes. Feedstock assay data are an
important tool in the refining process.
Octane rating or octane number is a standard measure of the
performance of an engine or aviation fuel. The higher the octane
number, the more compression the fuel can withstand before
detonating (igniting). In broad terms, fuels with a higher octane
rating are used in high performance petrol engines that require
higher compression ratios. In contrast, fuels with lower octane
numbers (but higher cetane numbers) are ideal for diesel engines,
because diesel engines (also referred to as compression-ignition
engines) do not compress the fuel but rather compress only air
and then inject the fuel into the air heated up by compression.
Petrol engines (also referred to as gasoline engines) rely on
ignition of air and fuel compressed together as a mixture without
ignition, which is then ignited at the end of the
compression stroke using spark plugs. Therefore, high
compressibility of the fuel matters mainly for petrol engines. Use
of petrol (gasoline) with lower octane numbers may lead to the
problem of engine knocking.[1]
The tonne of oil equivalent (toe) is a unit of energy defined as
the amount of energy released by burning one tonne of crude oil.
It is approximately 42 gigajoules, although as different crude oils
have different calorific values, the exact value is defined by
convention; several slightly different definitions exist. The toe is
sometimes used for large amounts of energy.
In a piston engine, the valve timing is the precise timing of the
opening and closing of the valves. In an internal combustion
engine these are usually poppet valves and in asteam
engine they are usually slide valves or piston valves.
The heat of combustion ( ) is the energy released
as heat when a compound undergoes
complete combustion with oxygen under standard conditions. The
chemical reaction is typically a hydrocarbon reacting with oxygen
to form carbon dioxide, water and heat. It may be expressed with
the quantities:
energy/mole of fuel (kJ/mol)
energy/mass of fuel
energy/volume of the fuel
The heat of combustion is conventionally measured with a bomb
calorimeter. It may also be calculated as the difference between
the heat of formation of the products and reactants.
The compression ratio of an internal-combustion
engine or external combustion engine is a value that represents
the ratio of the volume of its combustion chamber from its largest
capacity to its smallest capacity. It is a fundamental specification
for many common combustion engines.
In a piston engine, it is the ratio between the volume of
the cylinder and combustion chamber when the piston is at
the bottom of its stroke, and the volume of the combustion
chamber when the piston is at the top of its stroke.
An engine or motor is a machine designed to
convert energy into useful mechanical motion.[1][2] Heat engines,
including internal combustion engines and external combustion
engines (such as steam engines) burn a fuel to create heat, which
then creates motion. Electric motors convert electrical energy
into mechanical motion, pneumatic motors use compressed
air and others—such as clockwork motors in wind-up toys—
use elastic energy. In biological systems, molecular motors,
like myosins in muscles, usechemical energy to create motion.
The melting point (or, rarely, liquefaction point) of a solid is
the temperature at which it changes state from solid to liquid at
atmospheric pressure. At the melting point the solid and liquid
phase exist in equilibrium. The melting point of a substance
depends on pressure and is usually specified
at standard pressure. When considered as the temperature of the
reverse change from liquid to solid, it is referred to as
the freezing point or crystallization point. Because of the
ability of some substances to supercool, the freezing point is not
considered as a characteristic property of a substance. When the
"characteristic freezing point" of a substance is determined, in
fact the actual methodology is almost always "the principle of
observing the disappearance rather than the formation of ice",
that is, the melting point.[1]
The density, or more precisely, the volumetric mass density,
of a substance is its mass per unit volume. The symbol most often
used for density is ρ (the lower case Greek letter rho).
Mathematically, density is defined as mass divided by volume:
In cooking, the smoke point of an oil or fat is the temperature at
which, under defined conditions, enough volatile compounds
emerge from the oil that a bluish smoke becomes clearly visible.
At this temperature, volatile compounds, such as water, free fatty
acids, and short-chain degradation products of oxidation come up
from the oil. The smoke point is the temperature at which the oil
is decomposed and where possibly toxicological relevant
compounds are formed.
The smoke point for an oil varies widely depending on origin and
refinement.[1] The smoke point of an oil does tend to increase
as free fatty acid content decreases and degree of refinement
increases.[2][3] Heating the oil produces free fatty acid and as this
heating time increases, more free fatty acids are produced,
thereby decreasing smoke point. It is one reason not to use the
same oil to deep fry more than twice.[1] Intermittent frying has a
markedly greater effect on oil deterioration than continuous
frying.[4]
Considerably above the temperature of the smoke point is
the flash point, the point at which the vapours from the oil can
first ignite when mixed with air.
The autoignition temperature or kindling point of a
substance is the lowest temperature at which it
will spontaneously ignite in a normal atmosphere without an
external source of ignition, such as a flame or spark. This
temperature is required to supply the activation energy needed
for combustion. The temperature at which a chemical will ignite
decreases as the pressure or oxygen concentration increases. It is
usually applied to a combustible fuel mixture. Autoignition
temperatures of liquid chemicals are typically measured using a
500 mL flask placed in a temperature controlled oven in
accordance with the procedure described in ASTM E659.
The boiling point of a substance is the temperature at which
the vapor pressure of the liquid equals the pressure surrounding
the liquid[1][2] and the liquid changes into a vapor.
A liquid at high-pressure has a higher boiling point than when that
liquid is at atmospheric pressure. In other words, the boiling point
of a liquid varies depending upon the surrounding environmental
pressure. For a given pressure, different liquids boil at different
temperatures.
The normal boiling point (also called the atmospheric boiling
point or the atmospheric pressure boiling point) of a liquid is
the special case in which the vapor pressure of the liquid equals
the defined atmospheric pressure at sea level, 1atmosphere.[3]
[4] At that temperature, the vapor pressure of the liquid becomes
sufficient to overcome atmospheric pressure and allow bubbles of
vapor to form inside the bulk of the liquid. The standard boiling
point has been defined by IUPACsince 1982 as the temperature
at which boiling occurs under a pressure of 1 bar
Combustibility is a measure of how easily a substance will set
on fire, through fire or combustion. This is an important property
to consider when a substance is used for construction or is being
stored. It is also important in processes that produce combustible
substances as a by-product. Special precautions are usually
required for substances that are easily combustible. These
measures may include installation of fire sprinklers or storage
remote from possible sources of ignition.
Substances with low combustibility may be selected for
construction where the fire risk needs to be reduced.Like
apartment buildings, houses,offices and so on. If combustible
resources are used there is greater chance of fire accidents and
deaths. Fire resistantsubstances are preferred for building
materials and furnishings.
Thermal energy is a term sometimes used to refer to the
internal energy present in a system in a state of thermodynamic
equilibriumby virtue of its temperature.[1] The average
translational kinetic energy possessed by free particles in a
system of free particles in thermodynamic equilibrium (as
measured in the frame of reference of the center of mass of that
system) may also be referred to as the thermal energy per
particle
A temperature is a comparative objective measure of hot and
cold. The comparison is through detection of heat radiation,
particle velocity, kinetic energy, or most commonly, by the bulk
behavior of a thermometric material. It may be calibrated in any
of varioustemperature scales, Celsius, Fahrenheit, Kelvin, etc.
The latent internal energy of a system is the internal energy a
system requires to undergo a phase transition. Its value is specific
to the substance or mix of substances in question. The value can
also vary with temperature and pressure. Generally speaking the
value is different for the type of phase change being
accomplished. Examples can include Latent internal energy of
vaporization (liquid to vapor), Latent internal energy of
crystallization (liquid to solid) Latent internal energy of
sublimation (solid to vapor). These values are usually expressed
in units of energy per mass or per mole such as J/mol or BTU/lb.
Often a negative sign will be used to represent energy being
withdrawn from the system, while a positive value represents
energy being added to the system. However, reference sources
do vary so check the source to be sure.