Chapter # 2Literature Review

2.1) History of Brake Fluids In the 1920's, when automobiles started switching from mechanical brakes actuated by cables and levers to hydraulic brakes, the only material available for the required flexible hoses was natural rubber. As a result, a hydraulic fluid compatible with natural rubber was required for this application and a mixture of castor oil and alcohol was found to meet this need. The use of this fluid enabled the development of hydraulic brakes in the 1920's before synthetic rubbers became available. However, it fixed this industry on the use of hydraulic fluids based on glycols, glycol ethers, alcohols, poly-glycols and other related compounds that can be used with elastomeric braking system components made of natural rubber, styrene, butadiene, ethylene, propylene rubber, or poly-chloroprene. As a result, brake fluids are completely different from any of the other fluids used in automotive systems. The first hydraulic system was devised in 1914 by American automotive pioneer Frederick Duesenberg, and Lockheed Corporation co-founder Malcolm Lougheed developed his own system in 1918. Today's Lockheed, Girling, and silicone brake fluids are so vastly superior to the old Girling "Green" and "Crimson", and Lockheed "Heavy Duty" fluids originally. The most notable advances have been in raising boiling points, improving compatibility with other brake fluids, reducing moisture absorption, and reducing corrosion.2.2) Brake System Fundamentals The main function of brake fluid is to transmit the force applied to the brake pedal to the brake pads and shoes. The foundation of any hydraulic system is Pascals Law, which is generally given as in a fluid at rest in a closed container, a pressure change in one part is transmitted without loss to every portion of the fluid and to the walls of the container. To do this efficiently, brake fluids must be non-compressible. In addition, they must also not boil at the highest operating temperatures encountered, not thicken or freeze at cold temperatures, not corrode or chemically react with any materials in the hydraulic system, and not decompose or form sludge, gum, or varnish at any temperature. They must lubricate internal moving parts, flow easily through small passages, have a long and stable shelf life, and be compatible with other brake fluids. When brakes are applied on a moving car, the kinetic energy of the vehicle in motion is converted into heat. The faster the car is moving and the faster it is stopped, the more heat is produced. Some of this heat soaks into the brake fluid. In the late 1940s, brake fluid with a boiling point of 235F was considered adequate. By about 1957, 302F was the lowest S.A.E. specification for a minimum boiling point for cars with drum brakes. Disc brakes presented new problems. In stopping faster (and often heavier) cars more quickly, they generated even more heat which had to be dissipated. Improvements in brake lining materials, brake drum and rotor design and metallurgy have also had a similar effect. To handle these higher temperatures, improvements had to be made in wheel cylinder and brake caliper seal design and materials. The extra heat created a requirement for brake fluid that would not boil at the new normal operating temperatures of vehicle brake systems. Brake fluids must not be allowed to boil for two reasons. The first is simple: the brakes won't work because the vapor bubbles formed in the boiling fluid are compressible, and pressing on the brakes will compress the bubbles without exerting any pressure on the brake pads or shoes. The second problem is more subtle, but equally serious in the long term. When brake fluid boils, the physical and chemical properties will be changed because some of the components will be affected. The brake fluid contains chemicals that inhibit corrosion and oxidation, and these chemicals are affected by very high temperatures. Brake fluid that has boiled will boil at a lower temperature in the future.2.3) Developments in Brake Fluids The first brake fluids developed in 1920s were a mixture based on castor oil, and the seals were made of leather. By the end of 1930s all U.S. automobiles have rubber seals in the brake hydraulic systems. In the U.S.A., ever-increasing use is being made of new brake fluid standards introduced in 1973, FMVSS No. 116 (DOT-3 and DOT-4), which are aimed at preventing the formation of vapor lock in brake systems: these standards have introduced the quality index boiling point of wet fluid or boiling point of brake fluid in working conditions. The standard J1703f, which was issued in 1975, is only a little different from its predecessor, with only slight changes in the test procedures. Current brake fluids are based on polyoxyalkylene glycols and monoalkyl ethers of these glycols, as these materials provide high point s and satisfactory low-temperature properties. In order to eliminate the harmful effect of water, it has been proposed that the brake fluids should include esters of boric acid with alcohols or with alkylene glycol ethers. After 40 years of research and development, a brake fluid that was acceptable under extreme operating conditions was developed. This fluid achieved low water pickup and good corrosion protection. The fluid also provides good lubrication qualities and rubber compatibility. This was silicone brake fluid and has been used in all military vehicles since the end of 1982.

Chapter # 3Experimental Setup3.1) Raw Materials The raw materials needed for the production of Ethyl Benzoate which is a base component for production of Hydraulic Brake Fluid on laboratory scale are as follows, 1. Ethanol2. Benzoic Acid3. Sulfuric Acid (Concentrated) 4. Sodium Carbonate (Solution)5. Ether (di-ethyl ether)

3.1.1) Ethanol Ethanol, also known as ethyl alcohol, alcohol, Methylcarbinol, grain alcohol, Ethyl hydroxide, Ethyl hydrate, Algrain, Anhydrol, Tecsol, is avolatile,flammable, colorless liquid with the structural formula CH3CH2OH, often abbreviated as C2H5OH or C2H6O. Ethanol is apsychoactive drugand is one of the oldestrecreational drugs still used by humans. Ethanol can causealcohol intoxicationwhen consumed. Best known as the type ofalcoholfound inalcoholic beverages, it is also used inthermometers, as asolvent, and as afuel. In common usage, it is often referred to simply asalcoholorspirits.3.1.1.1) Production of Ethanol Ethanol is produced both as apetrochemical, through the hydration of ethylene and, via biological processes, byfermentingsugars withyeast. The economics of process depends on prevailing prices of petroleum and grain feed stocks. Ethanol for use as an industrial feedstock or solvent is made frompetrochemicalfeed stocks, primarily by theacid-catalyzedhydration of ethylene, represented by thechemical equationC2H4+ H2O CH3CH2OH The catalyst is most commonlyphosphoric acid,adsorbedonto a porous support such assilica gelordiatomaceous earth. This catalyst was first used for large-scale ethanol production by theShell Oil Companyin 1947. The reaction is carried out with an excess of high pressure steam at 300C (572F). Ethanol for use inalcoholic beverages, and the vast majority of ethanol for use as fuel, is produced by fermentation. When certain species ofyeastmetabolize sugarin reduced-oxygen conditions they produce ethanol and carbon dioxide. The chemical equations below summarize the conversion:C6H12O62 CH3CH2OH + 2 CO2C12H22O11+ H2O 4 CH3CH2OH + 4 CO2 Fermentation is the process of culturing yeast under favorable thermal conditions to produce alcohol. This process is carried out at around 3540C (95104F). Toxicity of ethanol to yeast limits the ethanol concentration obtainable by brewing; higher concentrations, therefore, are usually obtained byfortificationordistillation.

3.1.1.2) Physical and Chemical Properties of Ethanol

Sr. # Properties

1Appearance

Colorless

2Density0.789 g/cm3(at 20C)

3Flash Point-5F

4Water SolubilityCompletely Soluble

5Flammable Range (LELUEL)3.3%19%

6Flash Point48F

7Ignition Temperature793F

8Melting Point173F

9Boiling Point173F

10Vapor Density1.49

11Vapor Pressure44 mmHg

3.1.2) Benzoic Acid Benzoic Acid is also known as Dracylic acid, Benzeneformic acid, Carboxybenzene, benzenecarboxylic acid, with formula C7H6O2(or C6H5COOH), is a colorless crystalline solid and a simplearomaticcarboxylic acid. The name is derived from gum benzoin, which was for a long time the only source for benzoic acid. Its salts are used as food preservatives and benzoic acid is an important precursor for the synthesis of many other organic substances. Thesaltsandestersof benzoic acid are known asbenzoates.

3.1.2.1) Production of Benzoic Acid Benzoic acid is produced commercially bypartial oxidationoftoluenewithoxygen. The process is catalyzed bycobaltormanganesenaphthenates. The process uses cheap raw materials, and proceeds in high yield.

U.S. production capacity is estimated to be 126,000tonnesper year (139,000 tons), much of which is consumed domestically to prepare other industrial chemicals. Benzoic acid is cheap and readily available, so the laboratory synthesis of benzoic acid is mainly practiced for its pedagogical value. It is a common undergraduate preparation. Benzoic acid can be purified by re-crystallization from water because of its high solubility in hot water and poor solubility in cold water. The avoidance of organic solvents for the re-crystallization makes this experiment particularly safe.

3.1.2.2) Physical and Chemical Properties of Ethanol

Sr. #Properties

1Appearance

colorless crystalline solid

2OdorFaint, pleasant odor

3Density1.2659 g/cm3

4Water Solubility2.9 g/L

5Vapor pressure0.001 hPa

6Flash Point250.7F

7Auto ignition Temperature1058 F

8Melting Point252.34F

9Boiling Point480.6F

10Refractive index1.539

11Viscosity1.26 mPa

3.1.3) Sulfuric Acid Sulfuric acid is a strong mineral acid with the molecular formula H2SO4. It is soluble in water at all concentrations. When it is mixed with water, a very exothermic reaction occurs and the energy released can be enough to heat the mixture to boiling. Therefore, concentrated sulfuric acid must be diluted by adding slowly to cold water while the mixture is stirred to dissipate the heat. Sulfuric acid has many applications, and is one of the top products of the chemical industry. Principal uses include lead-acid batteries for cars and other vehicles, ore processing, fertilizer manufacturing, oil refining, wastewater processing, and chemical synthesis. About 65% of sulfuric acid produced annually is used in the production of agricultural fertilizers.3.1.3.1) Production of Sulfuric Acid Sulfuric acid is produced from sulfur, oxygen and water via the conventional contact process.Contact process: In the first step, sulfur is burned to produce sulfur dioxide.S (s) +O2(g) SO2(g) This is then oxidized to sulfur trioxide using oxygen in the presence of avanadium (V) oxidecatalyst. This reaction is reversible and the formation of the sulfur trioxide is exothermic.

2SO2(g) +O2(g)2SO3 The sulfur trioxide is absorbed into 9798%H2SO4to formoleum(H2S2O7), also known as fuming sulfuric acid. The oleum is then diluted with water to form concentrated sulfuric acid.H2SO4(l) +SO3(g) H2S2O7(l)H2S2O7(l) +H2O(l) 2H2SO4(l)

Note that directly dissolvingSO3in water is not practical due to the highlyexothermicnature of thereactionbetween sulfur trioxide and water. The reaction forms a corrosive aerosol that is very difficult to separate, instead of a liquid.SO3(g) +H2O(l) H2SO4(l)

3.1.3.2) Properties of Sulfuric Acid

Sr. #Properties

1Molecular formula

H2SO4

2Molar mass 98.086 g/mol

3Appearance Clear, colorless, odorless liquid

4Density 1.84 g/cm3, liquid

5Melting point 10 C, 283 K, 50 F

6Boiling point 337 C, 610 K, 639 F

7Solubility in water miscible

8Acidity (pKa) -31.99

9Viscosity 26.7 cP (20 C)

10Flash pointNon-flammable

3.1.4) Sodium Carbonate Sodium carbonate(also known aswashing soda,soda ashandsoda crystals), Na2CO3, is asodiumsaltofcarbonic acid(soluble in water). It most commonly occurs as acrystallinehepta-hydrate, which readilyefflorescesto form a white powder, the monohydrate. Pure sodium carbonate is a white, odorless powder that absorbs moisture from the air, has an alkaline taste, and forms a strongly alkaline water solution. Sodium carbonate is domestically well known for its everyday use as awater softener.3.1.4.1) Production of Sodium CarbonateMining: Trona,trisodium hydrogendicarbonate dihydrate(Na3HCO3CO32H2O), is mined in several areas of the US and provides nearly all the domestic consumption of sodium carbonate. Large natural deposits found in 1938, such as the one nearGreen River, Wyoming, have made mining more economical than industrial production in North America. There are important reserves of Trona in Turkey; two million tons of soda ash has been extracted from the reserves near Ankara. It is also mined from some alkaline lakes such asLake Magadiin Kenya by dredging. Hot saline springs continuously replenish salt in the lake so that, provided the rate of dredging is no greater than the replenishment rate, the source is fully sustainable.Leblanc process: In 1791, the French chemistNicolas Leblancpatented a process for producing sodium carbonate from salt,sulfuric acid,limestone, and coal. First, sea salt (sodium chloride) was boiled in sulfuric acid to yieldsodium sulfateandhydrogen chloridegas, according to thechemical equation2NaCl+H2SO4Na2SO4+ 2HCl Next, the sodium sulfate was blended with crushedlimestone(calcium carbonate) and coal, and the mixture was burnt, producingcalcium sulfide.Na2SO4+CaCO3+ 2C Na2CO3+ 2CO2+CaS The sodium carbonate wasextractedfrom the ashes with water, and then collected by allowing the water to evaporate. The hydrochloric acid produced by theLeblanc processwas a major source of air pollution, and thecalcium sulfidebyproduct also presented waste disposal issues.Solvay process: In 1861, theBelgianindustrial chemistErnest Solvaydeveloped a method to convert sodium chloride to sodium carbonate usingammonia. TheSolvay processcentered around a large hollow tower. At the bottom, calcium carbonate (limestone) was heated to release carbon dioxide:CaCO3CaO+CO2 At the top, a concentrated solution of sodium chloride and ammonia entered the tower. As the carbon dioxide bubbled up through it, sodium bicarbonate precipitated:NaCl+NH3+CO2+H2ONaHCO3+NH4Cl The sodium bicarbonate was then converted to sodium carbonate by heating it, releasing water and carbon dioxide:2NaHCO3 Na2CO3+H2O+CO2 Meanwhile, the ammonia was regenerated from the ammonium chloride byproduct by treating it with the lime (calcium hydroxide) left over from carbon dioxide generation:CaO+H2OCa(OH)2Ca(OH)2+ 2NH4ClCaCl2+ 2NH3+ 2H2O Because the Solvay process recycles its ammonia, it consumes only brine and limestone, and hascalcium chlorideas its only waste product. This made it substantially more economical than the Leblanc process, and it soon came to dominate world sodium carbonate production.Hou's process: Developed by Chinese chemistHou Debangin 1930s. The earliersteam reformingbyproduct carbon dioxide was pumped through a saturated solution ofsodium chlorideand ammonia to produce sodium bicarbonate via the following reactions:NH3+CO2+H2ONH4HCO3NH4HCO3+NaClNH4Cl+NaHCO3 The sodium bicarbonate was collected as a precipitate due to its low solubility and then heated to yield pure sodium carbonate similar to last step of the Solvay.

3.1.4.2) Properties of Sodium Carbonate

Sr. #Properties

1Molecular formula

Na2CO3

2Molar mass 105.9885 g/mol (anhydrous)124.00 g/mol (monohydrate)286.14 g/mol (decahydrate)

3Appearance White solid, hygroscopic

4Density 2.54 g/cm3(anhydrous)2.25 g/cm3(monohydrate)1.51 g/cm3(heptahydrate)1.46 g/cm3(decahydrate)

5Melting point 851 C (anhydrous)100 C (monohydrate)33.5 C (heptahydrate)32 C (decahydrate)

6Boiling point 1633 OC (anhydrous)

7Solubility in water 71 g/L (0 C)215 g/L (20 C)455 g/L (100 C)

8Basicity (pKb) 3.67

9Refractive index1.485 (anhydrous)1.420 (monohydrate)1.405 (decahydrate)

3.1.5) Di-ethyl Ether Diethyl ether, also known asethyl ether,sulfuric ether, simplyether, orethoxyethane, is anorganic compoundin theetherclass with the formula(C2H5)2O. It is a colorless, highlyvolatileflammable liquid. It is commonly used as asolventand was once used as ageneral anesthetic. It has narcotic properties and has been known to cause temporarypsychological addiction, sometimes referred to asetheromania.3.1.5.1) Production of Di-ethyl Ether Most diethyl ether is produced as a byproduct of the vapor-phasehydrationofethyleneto makeethanol. This process uses solid-supportedphosphoric acidcatalystsand can be adjusted to make more ether if the need arises.Vapor-phasedehydrationof ethanol over somealuminacatalysts can give diethyl ether yields of up to 95%. Diethyl ether can be prepared both in laboratories and on an industrial scale by the acid ether synthesis.[23]Ethanolis mixed with a strong acid, typicallysulfuric acid, H2SO4. The acid dissociatesin the aqueous environment producinghydroniumions, H3O+. A hydrogen ionprotonatestheelectronegativeoxygen atom of theethanol, giving the ethanol molecule a positive charge:CH3CH2OH + H3O+ CH3CH2OH2++ H2O Anucleophilicoxygen atom of unprotonated ethanoldisplacesa water molecule from the protonated (electrophilic) ethanol molecule, producing water, a hydrogen ion and diethyl ether.CH3CH2OH2++ CH3CH2OH H2O + H++ CH3CH2OCH2CH3 This reaction must be carried out at temperatures lower than 150C in order to ensure that an elimination product (ethylene) is not a product of the reaction. At higher temperatures, ethanol will dehydrate to form ethylene. The reaction to make diethyl ether is reversible, so eventually anequilibriumbetween reactants and products is achieved. Getting a good yield of ether requires that ether be distilled out of the reaction mixture before it reverts to ethanol, taking advantage ofLe Chatelier's principle.

3.1.5.2) Properties of Di-ethyl Ether

Sr. #Properties

1Molecular formula

C4H10O

2Molar mass 74.12 g mol1

3Appearance Colorless liquid

4Density 0.7134 g/cm3, liquid

5Melting point 116.3 C, 156.9 K, 177.3 F

6Boiling point 34.6 C, 307.8 K, 94.3 F

7Solubility in water 69 g/L (20C)

8Viscosity0.224cP(25 C)

9Refractive index1.353

10Flash point45C

11Auto ignition temperature160C

12Explosive limits1.9-48.0%

3.2) Experimental Work3.2.1) Safety

Wear eye protection. Protective gloves should be worn when handling acids and ether. Proper ventilation should be provided in the laboratory. Ether is highly flammable, keep away from ignition sources. Concentrated sulfuric acid is very corrosive dense liquid, dehydrating agent, add very slowly by continuously cooling the flask with water. Do not empty the byproducts and unreacted chemicals into drains. 3.2.2) Preparation of Brake Fluid

3.2.2.1) Introduction Brake fluids transmit the pressure on the brake pedal of a vehicle to the brake shoes or pads, which rub on the wheels and slow them down. The fluids must withstand high pressures without being compressed: air bubbles and vapors prevent this. They need a high boiling point because heat is produced when the brakes are applied. The fluid must also be chemically unreactive. It has been found that certain esters meet these requirements best and industry uses esters from a glycol and boric acid. An ester is formed when an alcohol and an acid react.

3.2.2.2) Preparation of an Ester This experiment is to prepare an ester, ethyl benzoate, from ethanol and benzoic acid, and then to purify it. The reaction involved is slow and needs heat to get it working quickly. The reaction, which is reversible, i.e. it will go either way, is:

ACID + ALCOHOL ESTER + WATER To stop it reforming the acid and the alcohol, the water is removed with concentrated sulphuric acid. To enable the reaction to be heated for a long time and the liquid not to be lost, a condenser is placed over the boiling liquid so that the vapors is cooled and returned to the flask.

Measured 100 cm3 of ethanol into a flask. Slowly and carefully added 12 cm3 of concentrated sulphuric acid, cooling the flask as this is being done by placing it under a running tap. Weighed 28 g of benzoic acid and added to the flask. Arranged the apparatus as shown in Figure 1 and heated the flask over gauze so that it boils gently.

Figure 1: Heating the mixture under reflux

Adjusted the flow of water in the condenser so that no vapors appear above half way in the tube. Heated the flask for an hour, and then left for five minutes with the water running in the condenser to cool down the vapors. Rearranged the equipment as shown in Figure 2, and then heated the water gently. Any ethanol that has not reacted with the benzoic acid will boil at 78 C and was condensed and then collected. Kept heating the water until there was no boiling in the flask: then all the unchanged ethanol has been removed.

To remove any unchanged benzoic acid, added a solution of sodium carbonate in water containing 8 g in 100cm3 until the liquid has a pH of 8 (test with universal indicator paper). This changed the benzoic acid into sodium benzoate. The ethyl benzoate was separated from this by using the fact that ethyl benzoate dissolves in ether and sodium benzoate does not. Poured the liquid into a separating funnel, added 40 cm3 of ether, stoppered the funnel and shook for five minutes, removing the stopper occasionally. Left to settle, and then separated the two layers by pouring off the bottom layer. Collected the two layers, running the ether layer into a clean, dry flask. Added a further 10 cm3 of ether to the other liquid and repeated the operation. Add this ether layer to the original ether in the flask. To obtain the ethyl benzoate from this solution, distilled off the ether using the equipment shown in Figure 2. The ether boils well below the boiling point of water and is condensed and collected in the tube. This enables the ether to be recollected so that it can be used again. This recovery of the solvent is very important in industry where solvents are used a lot and much money can be saved by their recovery. When all the ether had been boiled off, removed the beaker of water and placed a tripod and gauze under the flask. Heated strongly with a Bunsen and collected the liquid boiling at between 200 C and 215 C in a container. This is the ethyl benzoate which can be used in the tests for suitability as a brake fluid described in next section.3.2.3) Tests on Brake Fluid

3.2.3.1) Introduction To find if a liquid will work well as a brake fluid, its properties must be tested. A brake fluid should:a) have a high boiling point;b) b) be tolerant to water mixing;c) give suitable flow rates over a wide temperature change: the liquid must not be syrupy (viscous) at low temperatures but must not get too thin at high temperatures, otherwise it will not lubricate the brake shoes or act as a seal;d) have no effect on rubber or plastic seals;e) assist metals to resist corrosion;f) be resistant to chemical change at high temperatures;g) provide good lubrication for moving parts in the system;h) mix with other brake fluids;i) Not lose much volume by evaporation in working. Industry needs to test all fluids used in braking systems to make sure that they are up to standard in each of these respects. Below are some experiments which were carried out in the laboratory to test whether the above properties are present. 3.2.3.2) Finding the Boiling PointApparatus and chemicals required Round-bottomed flask Liebig condenser Thermometer Bunsen burner Stand and clamp Anti-bumping granules The boiling point of a liquid can be found in the laboratory by following way. The method involves setting up the equipment as shown in Figure below.Fig 3: Boiling Point Measurement The best way to heat the flask is to use a variac-controlled heating mantle that fits the flask. However, a Bunsen burner can be used, and the flame was adjusted to give a constant boiling rate to the liquid. The liquid was heated until it boil, with a condenser liquid flowing at a rate to keep the vapors condensing and refluxing (the condensed liquid falls back into the original liquid). Adjusted the heat so that the liquid boil gently and refluxes at a rate of two to four drops per second. Left for five minutes to allow the condition to settle, and then taken the temperature reading every 30 seconds for two minutes and the average result was used. 3.2.3.3) Tolerance to water mixing In normal use, brake fluids absorb small amounts of water which percolate in from the surroundings through the brake hoses. This can affect the ability of the fluid to operate at low temperatures as ice may form in the pipes, blocking the system, and can lower the boiling point of the fluid, causing vapors to form in the brakes. The effect of water on the boiling point of a typical brake fluid is shown in the graph in figure.

Figure 4: Effect of moisture on boiling point of Brake FluidApparatus and chemicals required Measuring cylinder 250 cm3 Flask 250 cm3 Syringe 10cm3 Sample tube (2) Beaker 250 cm3 Fluids to test A sample of the test fluid can be contaminated with about 3 per cent water by measuring 200 ml of the fluid in a measuring cylinder and pouring it into a flask, then adding 6 ml of water from a syringe and shaking the flask for several minutes. This mixture can then be used for the following tests. Filled a small sample tube with the mixture, sealed it and left it in a freezer overnight. Tested the fluid for transparency and clearness by placing the tube over a piece of graph paper and observing the lines through it. Examined the liquid for traces of solid, turning it over several times. Another sample tube was taken and filled with liquid and place it in a beaker of water at 60 C. Left for ten minutes to allow the liquid to reach 60 C, then performed the same tests. 3.2.3.4) ViscosityApparatus and chemicals required Glass tube (0.5m long, about 0.5 cm diameter) Stopper to fit tube (2) Water bath to fit tube Fluids to test A glass tube about 0.5 m long was taken, sealed at the bottom, and filled to within 10 cm of the top with the fluid under test. Stoppered the top, then turned the tube upside down and found the time needed for the air bubble to travel the length of the tube. Left the tube in a freezer for half an hour, then repeated the experiment. Placed the tube in a water bath at 100 C for ten minutes and then repeated the experiment again. The quicker the bubble travels through the tube, the lower the viscosity of the liquid. For a successful brake fluid, the viscosity should remain constant over a large temperature range. Another experiment that can be used to measure the flow of a fluid is to take a glass tube 2 m long and about 2 cm internal diameter, fill it with the liquid under test, then drop a ball bearing down the tube. Find the time it takes for the ball bearing to reach the bottom of the tube. This can be tried at different temperatures and using different liquids to compare their viscosity.3.2.3.5) Effect on Rubber and Plastic CapsApparatus and chemicals required Rubber sheet Polypropene sheet Cork borer Micrometer screw gauge Magnifying glass Brake fluid IsopropanolUsing a cork borer, cut two pieces of rubber sheet about 2 cm in diameter. Two pieces of polypropene about the same size were taken. Measured the diameter of each of the four pieces using a micrometer gauge. Placed one piece of rubber and one piece of polypropene in the fluid under test and left for a week at room temperature. After a week, removed the rubber and Polypropene from the fluid. Held the pieces with tweezers and cleaned by rinsing in isopropanol, then dried in warm air. Measured the diameter of the pieces under test within fifteen minutes of removing them from the fluid. Using a magnifying glass, examined the surfaces for blistering, pitting, or other signs of disintegration. Compared these samples with the control samples which were not soaked in fluid. The fluid should not cause corrosion of any sort or cause the material to expand by more than 5 per cent.3.2.3.6) Effect on MetalsApparatus and chemicals required Samples of: Aluminum Brass Copper Cast iron Tinned iron Steel Tin cutters Emery cloth Isopropanol Beaker 250 cm3 Tweezers Brake fluid Access to balance A brake fluid must not corrode the metals with which it comes into contact. These metals may include cast iron, steel, tinned iron (tin plate), aluminum, brass, and copper. To test this, strips of each metal were suspended in the fluid. The strips were prepared by cutting pieces about 7 cm long and 1.8 cm across and making a small hole near one end. The strips can be cleaned with emery cloth and then were washed in isopropanol. Each strip was then handled only with tweezers. Weighed each piece accurately and noted the weight. Assembled the metal strips on a steel nail in the order tinned iron, steel, aluminum, cast iron, brass, and copper, ensuring a gap at the top by bending the strips slightly. Washed again in isopropanol to remove all dirt. Placed the metal strip assembly in a beaker and poured sufficient liquid to cover by about 1 cm. Left the assembly in the beaker in a water bath at about 80 C for a week. Allowed the strips to cool in the fluid at room temperature for an hour. Using tweezers removed the strips from the fluid; examine the strips for sediment and shook them to remove any sediment which might be present. Cleaned each strip by rubbing with a cloth soaked in isopropanol. Inspected each strip with a magnifying glass for signs of pitting and corrosion. Weighed each strip and found the differences in weight compared with the original weight. Found the weight loss per unit surface area of the metal (remember there are two sides to each plate). This is given by the formula:

Weight loss/unit surface area = Weight loss (mg)/Surface area (cm3)

3.2.3.7) Compatibility with other Brake FluidsApparatus and chemicals required Measuring cylinder 100 cm3 Beaker 250 cm3 Sample tube Brake fluid Ester Used a standard commercial brake fluid supplied in the lab for the following test. Mixed 50 ml of the fluid under test with 50 ml of the commercial fluid in a 100 ml measuring cylinder. Mixed the fluid well in a beaker and examined for any solid deposited and any layers forming. Poured into a sample tube, and then inspected a piece of graph paper through it to test for deformation of the lines. Placed the sample tube in the freezer for at least one hour, then repeated the test. Placed in boiling water for fifteen minutes and carried out the test again. These activities test the compatibility of the fluids at different temperatures.3.2.3.8) Loss of Fluid by EvaporationApparatus and chemicals required Petri dish Fluid Access to balance It is important that a brake fluid maintains its volume under working conditions or an air lock may develop, reducing the efficiency of the system and making the brakes 'spongy'. The amount of evaporation in a closed system can be found by weighing an empty glass Petri dish with its lid on, adding 25 ml of fluid from a measuring cylinder and then weighing again. The weight of fluid in the dish can then be calculated. Placed the dish (with the lid on) in a ventilated oven at 100 C for two days, then remove and left to cool at room temperature and weighed the dish again. Found the loss of weight of the fluid and expressed it as a percentage of the original. This can be repeated for each fluid.% loss of weight = loose of weight / original weight3.2.3.9) Lubricant The lubricant properties of a fluid are related to its viscosity. If the fluid is too thin, it runs off too easily; if it is too viscous, it offers resistance to movement and also lessens its ability not to corrode the metals involved in the movement.3.2.3.9) pH Value It is important that a brake fluid should not produce an acid reaction with the materials with which it comes into contact. The acceptable range for the pH of a brake fluid is between 7 and 11.5. To find the pH of the fluids under test, mixed 25 ml with 25 ml of a mixture of 80 per cent ethanol and 20 per cent water, which had been neutralized to a pH of 7. Determined the pH of the resulting solution by using universal indicator solution or a pH meter with a calibrated electrode.

Chapter # 4Results and Discussions4.1) Table of Results

Test no.PropertySample Guard DOT 3

1Dry Boiling Point170 oC180 oC

2Wet Boiling Point122 oC140 oC

3Specific Gravity0.98891.0841

4Viscosity4.54 Kg/mSec9.5 Kg/mSec

5Effect on RubberNo Significant EffectNo Effect

6Effect on CopperNo Significant EffectNo Effect

4.2) Discussins on Results

4.2.1) Boiling Point:

The dry boiling point of sample product produced is 170 oC. While the boiling point of Guard DOT 3 is 180 OC. Hence our product has value of dry boiling point much closer to the commercial product, although this small difference is due to absence of additives. Same is the case with wet boiling point.

4.2.2) Specific Gravity:

The specific gravity of sample product produced is 0.9889. while the specific gravity of Guard DOT 3 is 1.0841. This shows that our product has almost same value of specific gravity as that of commercial product.

4.2.3) Viscosity:The viscosity of sample product produced is 4.54 Kg/m Sec. while the viscosity of Guard DOT 3 is 9.50 Kg/m Sec. This difference in values of viscosities is due to the fact that many additives are added in commercial product to improve viscosity, while those additives are not added in our sample product. The additives which are commonly used to improve properties of Brake Fluids are:

1. Tributyl phosphate,2. Benzotriazole3. Tolytriazole4. Triethanol amine5. Cyclohexyl amine6. Dibutyl amine7. Dibutylhydroxy toluene8. Bisphenol A9. 3-diethanol aminopropyl Silane

4.2.4) Effect on Rubber:

There was no significant effect of sample product on rubber, as no swelling of rubber was occurred on keeping rubber dipped in sample product for five days. This indicates that our product is appropriate to be used against rubber.

4.2.5) Effect on Copper:

There was no significant corrosion effect of sample product on copper, as copper strip was not corroded on keeping dipped in sample product for seven days. This indicates that our product is appropriate to be used against copper tubes.