Undiluted

Plug-flow reactors have a decreasing concentration gradient from inlet to outlet, which means that toxic compounds in the feed remain undiluted during their passage along the reactor, and this may inhibit or kill many of the microorganisms within the... 

For complete acetylation of polyhydric compounds, such as glucose (p. 141) and mannitol (p. I42), even undiluted acetic anhydride is insufficient, and a catalyst must also be employed. In such cases, the addition of zinc chloride or anhydrous sodium acetate to the acetic anhydride usually induces complete acetylation. ... 

Liquid diazomethane CHjjNj, b.p. —24°, is an explosive compound and explosions may also occur in the gaseous state if the substance is dry and undiluted. The gas may be handled with safety by diluting it with nitrogen. For synthetical work, a dry ethereal solution of the gas is employed and this can be handled with safety due regard must, however, be paid to the poisonous... 

Ozone s presence in the atmosphere (amounting to the equivalent of a layer 3 mm thick under ordinary pressures and temperatures) helps prevent harmful ultraviolet rays of the sun from reaching the earth s surface. Pollutants in the atmosphere may have a detrimental effect on this ozone layer. Ozone is toxic and exposure should not exceed 0.2 mg/m (8-hour time-weighted average - 40-hour work week). Undiluted ozone has a bluish color. Liquid ozone is bluish black and solid ozone is violet-black. 

If undiluted diacetylene is required, the experiment can be carried out in the same way, but preferably on a smaller scale. 3 Traps should then be used and the stream of nitrogen should be slower. The boiling point of diacetylene is said to be about 10°C. The solutions of diacetylene probably can be stored (under nitrogen in the refrigerator) for at least 24 h without decomposition. Though explosions have never been experienced by the authors, it is advisable to handle diacetylene with the necessary respect. 

To determine the concentration of ethanol in cognac a 5.00-mF sample of cognac is diluted to 0.500 F. Analysis of the diluted cognac gives an ethanol concentration of 0.0844 M. What is the molar concentration of ethanol in the undiluted cognac ... 

Poly(acrylic acid) and Poly(methacrylic acid). Poly(acryHc acid) (8) (PAA) may be prepared by polymerization of the monomer with conventional free-radical initiators using the monomer either undiluted (36) (with cross-linker for superadsorber appHcations) or in aqueous solution. Photochemical polymerization (sensitized by benzoin) of methyl acrylate in ethanol solution at —78° C provides a syndiotactic form (37) that can be hydrolyzed to syndiotactic PAA. From academic studies, alkaline hydrolysis of the methyl ester requires a lower time than acid hydrolysis of the polymeric ester, and can lead to oxidative degradation of the polymer (38). Po1y(meth acrylic acid) (PMAA) (9) is prepared only by the direct polymerization of the acid monomer it is not readily obtained by the hydrolysis of methyl methacrylate. 

Health nd Safety Factors. Although propargyl alcohol is stable, violent reactions can occur in the presence of contaminants, particularly at elevated temperatures. Heating in undiluted form with bases or strong acids should be avoided. Weak acids have been used to stabilize propargyl alcohol prior to distillation. Since its flash point is low, the usual precautions against ignition of vapors should be observed. 

Environmental impact studies on NE have been performed. Although undiluted NE inhibits seed growth, no effect on plant growth was observed when exposed to 6, 000 ppm-min of NE and only minor effects were observed at the 60, 000 ppm-min exposure level (41). Exposure of microbial populations to 25% NE in air for seven hours showed normal growth. NE is not an o2one-depleting gas (20). 

Vents and flares are intended to take contaminants released from safety valves away from work areas. However, if an elevated vent is at the level of an occupiable platform on the same or an adjacent unit, a worker may, under certain wind conditions, be subject to the nearly undiluted effluent of a vent. Whereas such elevated platforms may rarely be occupied, a heavy exposure from a vent could incapacitate a worker or cause a fall. Tanks that vent only when being filled are common causes of this concern. The usual solution is to raise the vent above any occupiable platform or, at greater cost, to scmb the vent effluent. 

Toners ate full strength undiluted pigments used to strengthen tinctorially weak batches of pigments. Occasionally, dyes ate utilized as toners. The most common pigments used in ink manufacture ate as foUows. 

Other Properties. The glass-transition temperature for PPO is 190 K and varies htde with molecular weight (182). The temperature dependence of the diffusion coefficient of PPO in the undiluted state has been measured (182). 

Eye Irritation. Exposure of the eye to undiluted alkan olamines can cause serious injury. Solutions as dilute as 1% of monoethan olamine and monoisopropan olamine can cause some eye irritation. 

Diethanolamine, diisopropanolamine, and isopropan olamine mixtures are less irritating to the skin than MEA and MIPA however, any one of them may produce severe skin irritation, even mild bums, if contact is prolonged or frequently repeated. Occasional short contact should not result in more than slight irritation. Undiluted triethanolamine and triisopropan olamine are slightly to moderately irritating to the skin. A bum may result from prolonged and repeated contact. Short occasional contact and solutions of less than 10% concentration are unlikely to cause more than very slight irritation, if any. 

Undiluted DMAMP, AMP-95, and AB cause eye bums and permanent damage, if not washed out immediately. They are also severely irritating to the skin, causing bums by prolonged or repeated contact. Of these three aLkanolarnines, only AMP has been studied in subchronic and chronic oral studies. The principal effect noted was the action of AMP on the stomach as a result of its alkalinity. The no-observed-effect level (NOEL) in a one-year feeding study in dogs was 110 ppm in the diet. In general, the low volatility and appHcations for which these products are used preclude the likelihood of exposure by inhalation. 

The dermal adsorption of DEBT in humans has been studied in the Netherlands by appHcation of DEBT as undiluted technical material or as 15% solutions in alcohol. Labeled material was recovered from the skin, and absorption of DEBT was indicated by the appearance of label in urine after two hours of skin exposure. About 5—8% of the appHed treatments was recovered as metaboHtes from urine, and excretion of metaboHtes in the urine came to an end four hours after exposure ended. DEBT did not accumulate in the skin, and only a small (less than 0.08%) amount ended up in feces. Curiously, less has been absorbed through skin from 100% DEBT appHcation (3—8%, mean of 5.6%) than from 15% alcohol appHcation (4—14%, mean of 8.4%). These results have been described as consistent with previous absorption/metaboHsm studies using guinea pigs, rats, and hairless dogs. Other pubHcations on DEBT toxicology have been cited (92). 

In 1875, a paper by Winkler awakened interest in the contact process, first patented in 1831. Winkler claimed that successfiil conversion of SO2 to SO could only be achieved with stoichiometric, undiluted ratios of SO2 and O2. Although erroneous, this beUef was widely accepted for more than 20 years and was employed by a number of firms. Meanwhile, other German firms expended a tremendous amount of time and money on research. This culminated in 1901 with Knietsch s lecture before the German Chemical Society (3) revealing some of the investigations carried out by the Badische Anilin-iind-Soda-Fahrik. This revealed the abandonment of Winkler s theory and further described principles necessary for successfiil appHcation of the contact process. 

Human sensitization studies were negative at 10% solution (47). Undiluted benzyl alcohol produces moderate dermal irritation in guinea pigs and mild dermal irritation in rabbits (48,49). Severe eye irritation was noted in a rabbit study (50). Acute oral rat LD q values were reported between 1.23 and 3.10 g/kg (50—52). A dermal rabbit LD q value of 2.0 g/kg has been reported (49). Rats died after 2 h when exposed to a 200-ppm vapor concentration (53). Benzyl alcohol is readily oxidized in animals and humans to benzoic acid [65-85-0] which is then conjugated with glycine [56-40-6], and rapidly eliminated in the urine as hippuric acid [495-69-2] (54). 

Lipases have proven to be effective in prespotters and other liquid detergent formulations when used in undiluted form for pretreatment of tough fatty stains. The low water content on the fabric in this situation is believed to be responsible for the high catalytic activity (50). 

The aminolysis of esters of pyrimidine occurs normally to yield amides. The reagent is commonly alcoholic ammonia or alcoholic amine, usually at room temperature for 20-24 hours, but occasionally under refiux aqueous amine or even undiluted amine are used sometimes. The process is exemplified in the conversion of methyl pyrimidine-5-carboxylate (193 R = Me) or its 4-isomer by methanolic ammonia at 25 °C into the amide (196) or pyrimidine-4-carboxamide, respectively (60MI21300), and in the butylaminolysis of butyl ttracil-6-carboxylate (butyl orotate) by ethanolic butylamine to give A-butyluracil-5-carboxamide (187) (60JOC1950). Hydrazides are made similarly from esters with ethanolic hydrazine hydrate. 

Oxaziridines substituted in the 2-position with primary or secondary alkyl groups undergo decomposition at room temperature. In the course of some weeks, slow decomposition of undiluted compounds occurs, the pattern of which is analogous to that of acidic or alkaline N—O cleavage (Sections 5.08.3.1.3 and 4), Radical attack on a C—H bond in (109) effects N—O cleavage, probably synchronously (57JA5739). In the example presented here, methyl isobutyl ketone and ammonia were isolated after two hour s heating at 150 °C. 

Shortcut Equipment Design Methods tend to become buried in design procedures, even computer-based ones. Therefore they often become part of the mix and don t stand free as separate entities. This is not bad. These methods need to be placed wherever they are useful. However, it is also good to draw them out since many everyday problems can be solved with undiluted shortcuts. 

Established practice in the treatment field has been to dilute liquid alum prior to application. However, recent studies have shown that feeding undiluted liquid alum results in better coagulation and settling. This is reportedly due to prevention of hydrolysis of the alum. 

If a chemical process requires the concentrated form of the material, it may be feasible to store a more dilute form, and to concentrate the material by distillation or some other technique in the plant prior to introduction to the process. The inventory of material with greater intrinsic hazard (i.e., undiluted) is reduced to the minimum amount required to operate the process, but the distillation adds a new hazardous process. 

Note The detection limits per chromatogram zone arc ca. 1 pg substance in the case of aryl-substituted thioureas [4], but even at 50 pg per zone diallate and triallate did not produce any reaction [6]. The reagent should be employed undiluted (cf. Procedure Tested , Fig. 2). 

Fig. 2 The influence of the reagent concentration on the sensitivity of detection detection of equal amounts of luteolin with basic lead acetate solution that was (A) undiluted, (B) diluted 1 + 4 and (C) diluted 1 + 50.

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