Yeah!!! Come on NOW!!!

[Necronomicon]

Silicon dioxide heated with excess of magnesium forms magnesium silicide. The first product in this reaction is amorphous silicon, which then reacts with magnesium to produce Mg2Si,

 

SiO2 + 2 Mg ==> 2 MgO + Si

 

Si + 2 Mg ==> Mg2Si

 

Magnesium silicide interacts with hydrochloric acid to form silicon tetrahydride (silane or monosilane) and other silanes and magnesium chloride,

 

Mg2Si + 4 HCl ==> SiH4 + 2 MgCl2

 

Finally, the spontaneously inflammable silicone hydride reacts with the oxygen of the air.

 

SiH4 + 2 O2==> SiO2 + 2 H2O

 

To demonstrate the formation and combustion of silane we use the method suggested by L. Gattermann in 1889 [1-3]. When performing this experiment it is worth reminding the audience that silicon is the closest analogue of carbon in the Periodic Table and silane (SiH4) is therefore the analogue of methane (natural gas, CH4) which we burn in our gas burners. Silane however is much more reactive than methane and at ambient temperature does not require any excess energy to start oxidation; although we require some form of fire or spark in order to light methane in a gas burner, silane is spontaneously flammable in air.

 

Preparation of magnesium silicide can be carried out before the show. However, this reaction serves to show that, as in demonstration 17, reactions between solids are more difficult to achieve than between liquids or gasses. The mixture has to be heated to red heat before the reaction takes place, and a further rapid increase in temperature to a bright yellow heat indicates that this exothermic reaction has occurred.

 

 

 

Alternatively the formation of silicon hydride can be shown using the method of A Mermet (1887) [4]. By the interaction of magnesium and glass (calcium sodium silicate) silicon and magnesium silicide are formed. The product is treated with dilute acid to form silane. Place a 1-inch length of magnesium ribbon in a test tube (e.g., 5 x 5/8 in.). Let the magnesium slide to the bottom and rest upright against the side of the tube. Heat the tube gently, the ribbon flattens and adheres to the wall of the tube. Insert a second piece of magnesium about 1/4 of an inch from the first and repeat the heating. Continue until four pieces have been added. Now heat to redness until the magnesium blackens and seems to amalgamate with the glass. Allow the tube to cool. Now add a few cm3 of dilute hydrochloric acid. A gas is evolved which bursts into flame at the mouth of the tube, with the formation of a cloud of silica. The gas evolved is therefore a flammable silicon compound.

 

Source

Edited February 21, 2003 by Necronomicon

[Thinker]

Sounds like someone in Rhode Island got ahold of your chemistry lab notebook and tried that out last night....

[Necronomicon]

Rockin'!!!!

[iain]

once bitten twice shy

 

or as bush would say...bite me once....shame on....shame on me.....bite me twice......youdon'tgetboldagain.

[allthumbs]

Necro you tool, I told ya that was good shit.

[erik]

meth repceipes are not appropiate

[iain]

and then trask was all:

Vegetarian: Primitive word for lousy hunter.

that's some funny stuff right there. I'm sure you kill everything you eat. I bet that McRib put up a good struggle before you broke its neck and skinned it on site.

[Thinker]

erik said:

meth repceipes are not appropiate

 

The only reactant in the recipee above that could be used to cook meth is the hydrochloric acid. Sulfuric acid is preferred, though.

[iain]

thinker how's the new pad coming? cardboard boxes and plywood make great siding don't they

[erik]

Thinker said:

erik said:

meth repceipes are not appropiate

 

The only reactant in the recipee above that could be used to cook meth is the hydrochloric acid. Sulfuric acid is preferred, though.

 

i wouldn't even know, mine takes dirt, fish fertilizer, water and sunlight!

[Necronomicon]

Soon after metallic aluminium was first isolated, both Sainte-Claire Deville and Wöhler noted its property when mixed in the form of powder or granules with the oxides of some of the metals, of reducing them with the evolution of sufficient heat to melt the metal and the alumina produced [1].

 

On this was based the process applied by Dr Hans Goldschmidt of Essen, who in 1898 was developing commercially the promising work of Claude Vauntin and Hugh Picard in London, following the change in the economics of aluminium supply which had taken place when production by the Héroult and Hall electric furnace method superseded the expensive sodium reduction process; prior to that time the use of aluminium as a reducing agent was little more than a scientific curiosity [2]. Goldschmidt has obtained either the metal, or an alloy of the metal, with aluminium, from the oxides of chromium, manganese, iron, copper, titanium, boron, tungsten, molybdenum, nickel, cobalt, zirconium, vanadium, niobium, tantalum, cerium, thorium, barium, calcium, sodium, potassium, lead and tin. He said:

 

In a thermite reaction, a metallic compound is reduced by one of several metals or metallic alloys in such a way that when the mixture is ignited at one place, the reaction continues of its own accord, so that under complete oxidation of the reducing element, a fluid slag is formed, while the reduced metal is obtained as a homogeneous uniform regulus; if the oxide is used in excess, the reduced metal is free, or practically free, from the element used as a reducing agent.

 

 

 

Goldschmidt’s significant innovations comprised the means of starting the reaction by a fuse, instead of heating the mixture until ignition took place, and the various controlling procedures which made the process practicable on a plant scale. He also arranged ingenious adaptations to produce molten iron or steel for the welding and repair of rails and machine parts and for many years these have been familiar on tramways and railway systems and in rolling mills.

 

This is the first of two solid/solid reactions, see also experiment 18a. This reaction, uses powdered aluminium metal to reduce metallic oxides and is especially useful for the reduction of those metal oxides which are difficult to reduce such as titanium and molybdenum. It is also known as the Goldschmidt process, and the Aluminothermic process. This is a highly exothermic reaction and the metal emerges in its molten state often very much above its melting point. A mixture of finely divided aluminium with ferric oxide (or the oxide of some other metal), approximating to 2Al+Fe2O3, is sold under the registered name Thermit (no final ‘e’), and is used in joining or welding iron and steel rails, pipes, etc. Sections of railway lines are usually welded in this way and the reaction is mostly associated with the reduction of iron oxide as in our demonstration. Like the first part of the next demonstration this reaction takes place between solids and is, consequently, difficult to start.

 

Two equivalents of finely divided aluminium and one of iron oxide are mixed together and ignited. The reaction takes place as follows:

 

Fe2O3 + 2 Al ==> Al2O3 + 2 Fe + 848.54 kJ (17.1)

 

 

 

A great variety of practical application had been proposed for the thermite reaction. These included a successful slow-burning thermit which was devised during the Second World War for cartridges capable of heating cans of soup and other foods required on active service.

 

Source

Edited February 21, 2003 by Necronomicon

[Thinker]

erik said:

i wouldn't even know, mine takes dirt, fish fertilizer, water and sunlight!

 

I've just had the joy of cleaning up a few labs after they've been busted or dumped along side the road when the meth heads get too paranoid. After seeing what they use for solvents and catalysts there's no way in HELL I'd snort that stuff.

[Thinker]

iain said:

thinker how's the new pad coming? cardboard boxes and plywood make great siding don't they

 

Whatchoo talkin bout, Otis?

[Necronomicon]

18-Methyleicosanoic acid (18-MEA) is an unusual, methyl-branched chained saturated fatty acid that appears to be covalently attached, via a thioester linkage, to the outer surfaces of all mammalian keratin fibres; 18-MEA also forms the outer b-layer of the cuticular cell membrane complex (CCMC) which separates the cuticle cells from each other.1,2 The precise role of this specific fatty acid remains unclear,3 although the large segmental volume of the anteiso-terminus is expected to exhibit considerable molecular mobility and liquid-like behaviour compared to straight-chained analogues.4 Cosmetic companies are interested in 18-MEA as it may confer a conditioning benefit to hair surfaces.5

Synthesis of 18-MEA, a preferred method over bulk extraction from wool fibres, has been reported in a patent by the Kao Corporation (Scheme 1).5 The synthesis involves bromination of the commercially available 2-methyl-1-butanol (1), using hydrobromic acid (48%), to produce 1-bromo-2-methylbutane (2) and subsequent treatment with triphenylphosphine to yield 2-methylbutyltriphenylphosphonium bromide (3).5 A Wittig condensation of 3 with methyl 15-formylpentadecanoate affords the unsaturated ester that is then reduced (H2/PtO2) and hydrolysed to yield 18-MEA (4).

 

 

 

 

 

 

Scheme 1.

 

 

 

 

 

 

A modified synthesis of 18-MEA was recently reported by Cundy and Gurr.6 The method uses a "Julia coupling", where the anion generated from a substituted benzothiazolylsulfone reacts with a carbonyl compound to yield an unsaturated ester. The Julia method, which has its own limitations, was used to eliminate the long time period required (3 days) to synthesise 2 from 1. In parallel, the same authors also followed the hydrobromic acid method to yield 2 in 75% yield; an N-bromosuccinimide mediated procedure7 was unsuccessful in improving the yield.

We recently synthesised 18-MEA closely following the Kao Corp. method.5 Our interest was to investigate the adhesion properties, using atomic force microscopy (AFM), of self-assembled monolayers of 18-MEA and analogues to silanised mica surfaces.8 In following the first step of the synthesis, bromination of 1 to 2, we obtained a mixture of bromination products. In this paper, we report an alternative synthesis that greatly improves the yield of the required bromination product (2).

 

 

 

--------------------------------------------------------------------------------

 

Results and Discussion

The mixture of products obtained from the bromination of 1 using hydrobromic acid (48%) were identified using GCMS (Table 1).

 

 

 

 

 

 

Table 1. Mixture of products obtained from bromination of 1 using hydrobromic acid.

 

Peak RTa Compound %b

1 1.6 2-methylbut-1-ene 4.0

2 4.5 2-bromo-2-methylbutane 14.1

3 5.4 2-bromo-2-methylbutane 8.6

4 5.6 2-bromopentane 4.5

5 5.9 3-bromopentane 5.8

6 6.5 1-bromo-2-methylbutane (2) 54.2

 

aRetention time / min; bComponents 1% shown only.

Bromination using hydrobromic acid proceeds via an SN1 pathway, involving the formation of a carbocation that can undergo rearrangement; this is the most likely explanation for the resultant mixture of products, where the required 1-bromo-2-methylbutane (2) was obtained in only 54% yield. Since separation of the bromo compounds would prove difficult, due to similarities in boiling points,9 and expensive on scale-up, an improved bromination method using red phosphorus and bromine, which directed an SN2 pathway, was used.10 The absence of carbocation rearrangement led to a high relative yield of 2 (85%) (Table 2).

 

 

 

 

 

 

Table 2. Mixture of products obtained from bromination of 1 using red phosphorus and bromine.

 

Peak RTa Compound %b

1 4.4 2-methylbutan-1-ol (1) 1.6

2 4.4 2-bromo-2-methylbutane 1.4

3 5.9 1-bromo-3-methylbutane 4.1

4 6.4 1-bromo-2-methylbutane (2) 85.4

5 11.6 1,3-dibromo-3-methylbutane 3.7

 

aRetention time / min; bComponents 1% shown only.

The product, 2, was distilled directly from the reaction mixture. Attempts to add water prior to an ether extraction step and for the removal of excess phosphorus,10 resulted in the formation of oxidation products, such as 3-methylbutan-2-one (1.0%), 1,1'-oxybispentane (3.0%) and 2-methylbutanoic acid (4.4%) and a reduction in the yield of 2 (to 56%).

In conclusion, an alternative route to 2, a bromo precursor compound for the synthesis of 18-MEA, is presented. The method produces 2 in much higher purity than that obtained from the use of hydrobromic acid, thus conserving the anteiso-terminus of the branched chain fatty acid, 18-MEA.

 

 

 

--------------------------------------------------------------------------------

 

Experimental

Bromination of 1 using hydrobromic acid: Sulphuric acid (conc., 52 g) in hydrobromic acid (48%, 161 g, 0.739 mol) was added to 1 (65 g, 0.430 mol) and the mixture gently refluxed for 72 h. Subsequent distillation yielded 2 as a colourless oil, 87.6 g (79%; lit. 72%5), which was dried over CaCl2.

Bromination of 1 using red phosphorus and bromine: A suspension of red phosphorus (4.57 g, 0.147 mol) in 1 (65 g, 0.739 mol) was stirred under gentle reflux in a 500 cm3 three-necked flask fitted with a dropping funnel containing bromine (59.0 g, 0.369 mol). Bromine was introduced slowly at such a rate that only a small amount of bromine vapour appeared above the reaction mixture. Refluxing was continued for 30 min. and then the apparatus was rearranged for distillation to yield 2 as a colourless oil, 74.1 g (67%), b.p. 121 °C, lit. 121.6 °C,9 which was dried over CaCl2. 1H NMR (CDCl3): d 0.91 (t, CH3, 3H), 1.01 (d, 2-CH3, 3H), 1.29 (m, MeCH2,1H), 1.49 (m, MeCH2',1H), 1.73 (m, EtCH(Me), 1H), 3.37 (m, CH2-Br, 2H) ppm; 13C NMR (CDCl3): d 11.27 (2-CH3), 18.39 (n-CH3), 21.92, 27.61 (CH3CH2-), 36.80 (-CH2-CH(Me)-CH2-), 41.15 (CH2-Br) ppm; MS (m/z): 27, 29, 39, 41, 42, 43, 55, 57, 71, 80, 93, 107, 121, 123, 150 (M+), 152 ([M+2]+).

GCMS: HP5890 GC with HP5971 MSD; scan mode 35 to 450 amu; SGE BPX5 25 m x 0.2 mm x 0.25 µm, bonded phase capillary column; He carrier gas, u = 1 cm3 min-1; injector temp. 250 °C, split injection at 20:1, injection size 1.0 µl; detector temp. 280 °C; oven programme: initial temp. 40 °C for 5 min., then ramped at 6 °C min-1 to 200 °C and held for 5 min.

 

Source

 

Edited February 21, 2003 by Necronomicon

[erik]

Thinker said:

erik said:

i wouldn't even know, mine takes dirt, fish fertilizer, water and sunlight!

 

I've just had the joy of cleaning up a few labs after they've been busted or dumped along side the road when the meth heads get too paranoid. After seeing what they use for solvents and catalysts there's no way in HELL I'd snort that stuff.

 

i dunno man, snorting battery acid, cold pills and what not cant be all that bad for you?!?!?!

[iain]

I like a good lithium sandwich now and then, washed down with some drain cleaner and lye. Breakfast - most important meal of the day

[Necronomicon]

iain said:

I like a good lithium sandwich now and then, washed down with some drain cleaner and lye. Breakfast - most important meal of the day

 

A. Lanthanum-lithium-®-BINOL complex (LLB). A dry, 300-mL, three-necked flask equipped with a magnetic stirring bar, septum cap, and a rubber balloon filled with argon, is charged with ®-2,2'-dihydroxy-1,1'-binaphthyl (®-BINOL; 6.49 g, 22.7 mmol, Note 1) and 119 mL of tetrahydrofuran (THF, Note 2) under an argon atmosphere. The system is placed in an ice-water bath and magnetic stirring is initiated. Via syringe, 28.4 mL (45.4 mmol) of a 1.60 M hexane solution of butyllithium (Note 3) is added to the cooled ®-BINOL solution over 7 min and the pale yellow mixture is stirred for an additional 15 min. The cooling bath is removed and the THF solution of ®-BINOL dilithium salt is allowed to reach room temperature.

A 500-mL, two-necked, round-bottomed flask equipped with a magnetic stirring bar, reflux condenser, and a septum cap is charged with 3.12 g of lanthanum trichloride heptahydrate (LaCl3 · 7H2O, 8.4 mmol, Note 4) and 100 mL of THF. The resulting suspension is sonicated for 30 min at room temperature (Note 5). To this suspension is added the above prepared solution of ®-BINOL dilithium salt via syringe over 5 min with vigorous stirring (Note 6). After this mixture is stirred for 30 min at room temperature, a 0.52 M THF solution of sodium tert-butoxide (4.85 mL, 2.52 mmol, Note 7) is added via syringe over 5 min. The resulting suspension is stirred vigorously for 14 hr at room temperature and then stirred for 48 hr at 50°C. The reaction mixture is allowed to cool to room temperature without stirring, and the supernatant is used as a 0.03 M solution of lanthanum-lithium-®-BINOL catalyst [®-LLB].

B. (2S,3S)-2-Nitro-5-phenyl-1,3-pentanediol. A 500-mL, two-necked, round-bottomed flask equipped with a magnetic stirring bar, septum cap, and a rubber balloon filled with argon, is charged with 119 mL of THF and a 0.03 M THF solution of ®-LLB catalyst (63.3 mL, 1.90 mmol) under an argon atmosphere. The system is cooled to −40°C and magnetic stirring is initiated (Note 8). The mixture is stirred for 30 min at −40°C, then 2-nitroethanol (3.00 mL, 41.8 mmol, Note 9) is added via syringe over 4 min. After 30 min of stirring at −40°C, 5.00 mL of 3-phenylpropanal (38.0 mmol, Note 10) is added via syringe over 5 min and the resulting solution is stirred for 90 hr. The reaction is monitored by TLC (Note 11). To the reaction mixture is added 150 mL of 1N hydrochloric acid (HCl). To this mixture is added 20 g of sodium chloride (NaCl) and the resulting mixture is transferred to a 2-L separatory funnel. The aqueous phase is extracted three times with ethyl acetate (400, 200, and 200 mL) and the combined organic phases are washed with 350 mL of aqueous saturated NaCl solution and dried over sodium sulfate. The solvent is removed with a rotary evaporator, and the resulting crude product is recrystallized from 1 : 1 hexane: ether (ca. 200 mL) to give 4.31g (50%) of analytically pure (2S,3S)-2-nitro-5-phenyl-1,3-pentanediol (98% ee, Notes 12-15).

 

Source

Edited February 21, 2003 by Necronomicon

[iain]

don't knock the meth lab! It's a great source of hydrogen for bush's little forays into alternative transportation

[Thinker]

iain said:

don't knock the meth lab! It's a great source of hydrogen for bush's little forays into alternative transportation

 

And if something goes wrong, it's a great fireworks display for the neighbors....

[Necronomicon]

iain said:

don't knock the meth lab! It's a great source of hydrogen for bush's little forays into alternative transportation

 

GUIDELINES FOR INDIVIDUAL EUTHANASIA METHODS

 

Carbon Dioxide

 

Carbon dioxide can be used from compressed gas cylinders. Animals are usually placed in an enclosed container (e.g., a bell jar or specially designed euthanasia chamber) in which CO2 displaces the ambient air. Since CO2 is heavier than air it accumulates in the bottom of the container, and euthanasia is most rapid if the animals are confined in the lower portion of the container.

 

If the animals are placed in the chamber before filling with CO2, then the flow rate for the gas should be adjusted to displace approximately 20% of the chamber volume per minute. The sound generated by the rapidly expanding gas can be such that it is distressful to the animals, so attempts should be made to muffle the noise. If animals are placed in a chamber that has been prefilled with at least 70% CO2, unconsciousness is induced more rapidly and the issue of noise is avoided.

 

Neonatal animals require prolonged exposure to CO2 and it may be necessary to use an additional means to confirm death (e.g., decapitation under CO2 anesthesia).

 

Cervical Dislocation

 

Cervical dislocation is suited for poultry and other small birds, mice and rats < 200 grams. Since there exists some uncertainty about the animal's perception of pain during this procedure, its use in unanesthetized animals requires scientific justification. Animals can be euthanized by cervical dislocation under anesthesia without scientific justification.

 

As with other physical means of euthanasia, training and experience are essential to the rapid induction of unconsciousness and the successful performance of euthanasia by this technique. For those unfamiliar with this technique, please contact the CMU at ext. 6555 for training.

 

For mice, the animal is placed on a flat surface, restrained by the base of the tail in one hand while the thumb and first two fingers of the other hand restrain the head. The first finger of the hand restraining the head is placed immediately behind the skull and the tail is used to rapidly elevate the body and pull it back while simultaneously thrusting the finger down to dislocate the cervical vertebrae. Alternatively, a sturdy rod of approximately 0.75 cm diameter can be placed behind the head in place of the hand restraint of the head. Cervical dislocation is accomplished by elevating the body as described while pressing down with the rod.

 

Decapitation

 

Decapitation is usually accomplished using a commercially available guillotine and is most frequently used with small rodents such as rats. The procedure is generally regarded as aesthetically unpleasant, but it is an important method of euthanasia in those projects in which it is important to collect unadulterated tissue. As with cervical dislocation, its use in unanesthetized animals requires scientific justification as a part of the protocol review process.

 

Decapitation can be performed in amphibians and reptiles using heavy sheers, however it must be followed by pithing and requires scientific justification.

 

The blades of the guillotine or shears must be maintained in a sharp condition.

 

Euthanasia Solution

 

Most commercially available euthanasia solutions contain a high concentration of pentobarbital in propylene glycol and isopropyl or ethyl alcohol. They are administered by the intravenous route for those species with accessible veins (e.g., cats, rabbits, dogs, pigs, sheep). For rodents and other small mammals, they can be administered by intraperitoneal injection. The intracardiac route can be used only in fully anesthetized or unconscious animals. The usual dose is 1 ml per 10 pounds of body weight; however, the manufacturer's instructions should be followed.

 

Exsanguination

 

Exsanguination is often used where it is necessary to collect large volumes of blood from an animal. Exsanguination is approved only in fully anesthetized animals.

 

Inhalant Anesthetic Agents

 

In order of preference, halothane, enflurane and isoflurane are acceptable for euthanasia. For small animals (e.g., laboratory rodents and bats) administration in an enclosed chamber is suitable. For larger species inhalants should be administered with a vaporizer.

 

When using inhalants in neonatal animals it may be necessary to use an additional means of euthanasia to confirm death (e.g., decapitation or exsanguination under anesthesia).

 

Ether and methoxyflurane are conditionally acceptable.

 

Pentobarbital

 

Overdoses of pentobarbital are commonly used for euthanasia. Like the commercially available euthanasia solutions it is best given intravenously, although the intraperitoneal route is suitable for rodents and other small mammals. The intracardiac route can be used only in fully anesthetized or unconscious animals. The dose for euthanasia should be 120 mg/kg or greater. As for any method of euthanasia, death must be confirmed before disposal.

 

Pithing

 

Generally pithing is considered an adjunctive method of euthanasia suitable only for certain amphibians and reptilian species. For frogs, double pithing is conditionally acceptable. For other species, pithing must be accompanied by another means to achieve euthanasia.

 

Source

Edited February 21, 2003 by Necronomicon

[iain]

I remember a jar of lithium in the organic chem stockroom with some grey waxy-looking sticks in it with some tape on the top that read "whatever you do, do not open this container - will explode on contact with air"

[erik]

necro remember as any good scientist would cite their sources!!!

 

 

[Necronomicon]

iain said:

I remember a jar of lithium in the organic chem stockroom with some grey waxy-looking sticks in it with some tape on the top that read "whatever you do, do not open this container - will explode on contact with air"

 

The chemical properties of lithium resemble those of sodium, but its reactions are the least reactive for the alkali metals group. However, lithium is still highly reactive chemically, and must be stored under liquid paraffin, which contains no oxygen, to prevent oxidation.

Lithium burns readily in air forming a mixture of lithium suboxide.

 

 

 

4 Li + O2 ==> 2 Li2O

 

Lithium reacts readily with the halogens, forming the appropriate lithium salt.

 

 

2 Li + Cl2 ==> 2 LiCl

 

Lithium reacts violently with water, forming lithium hydroxide and liberating hydrogen.

 

2 Li + 2 H2O ==> 2 LiOH + H2(g)

 

Source

Edited February 21, 2003 by Necronomicon

[allthumbs]

I nominate Necro and Mtn. Goat for the most close-minded, bullshit post award.

[iain]

we also took a chunk of pure sodium out to a rock quarry and used a bike tube to launch it into the middle of the lake. We could see our shadows on the trees as we ran away.