Acid loss

Calcium fluoride loss is equal to 3.9% for each 1% sihca sulfuric acid loss is equal to 4.9% for each 1% sihca. 

Sulfuric acid loss is approximately 1.84% H2SO4 for each percentage of R2O2. Oleum consumption is increased to consume the water that is formed. The metal sulfates are more stable than metal fluorides under furnace conditions and are discharged from the process with the residue. 

Calcium C rbon te. Calcium carbonate, like R2O2, affects sulfuric and oleum consumption in the HF process. Sulfuric acid loss is approximately 0.98% H2SO4 for each percentage of CaCO. The carbon dioxide evolved by the reaction increases the noncondensable gas flow, and because it carries HF, contributes to yield losses in the vent stream. 

The calcium form of EDTA instead of free EDTA is used in many food preparations to stabilize against such deleterious effects as rancidity, loss of ascorbic acid, loss of flavor, development of cloudiness, and discoloration. The causative metal ions are sequestered by displacing calcium from the chelate, and possible problems, such as depletion of body calcium from ingestion of any excess of the free chelant, had it been used, are avoided. 

An ipso attack on the fluorine carbon position of 4-fIuorophenol at -40 °C affords 4-fluoro-4-nitrocyclohexa-2 5-dienone in addtion to 2-nitrophenol The cyclodienone slowly isomenzes to the 2-nitrophenol Although ipso nitration on 4-fluorophenyl acetate furnishes the same cyclodienone the major by-product is 4 fluoro-2,6-dinitrophenol [25] Under similar conditions, 4-fluoroanisole pnmar ily yields the 2-nitro isomer and 6% of the cyclodienone The isolated 2 nitro isomer IS postulated to form by attack of the nitromum ion ipso to the fluorine with concomitant capture of the incipient carbocation by acetic acid Loss of the elements of methyl acetate follows The nitrodienone, being the keto tautomer of the nitrophenol, aromatizes to the isolated product [26] (equation 20) Intramolecular capture of the intermediate carbocation occurs in nitration of 2-(4-fluorophenoxy)-2-methyIpropanoic acid at low temperature to give the spiro products 3 3-di-methyl-8 fluoro 8 nitro-1,4 dioxaspiro[4 5]deca 6,9 dien 2 one and the 10-nitro isomer [2d] (equation 21)... 

Possible Precursor Compounds Carboxylic acids (loss of OH)... 

Ortho substituent of methyl esters of aromatic acids. Loss of 31 also should be present. 

Loss of C(0)0CH3 from methyl esters Loss of OC3H7 from propyl esters Methyl esters of 2-hydroxycarboxylic acids Loss of CH3C(0)0 from sugar acetates... 

Certain esters of dibasic carboxylic acids Loss of (C3H9SiF) for fluorinated sugars... 

Loss of -C(CH3)2C(0)0CH3 jV-TFA, /i-butyl amino acids Loss of (-C(0)0C4H9)... 

Methyl esters of unsaturated acids (loss of CH3OH + HzO) Methyl esters of straight-chain hydroxycarboxylic acids except 2-hydroxy acids... 

Methyl esters of short-chain dicarboxylic acids Loss of — OCH2CH2NH2 -C6H10(CO2CH3)2 O-methyl toluates... 

Protein and amino acid losses through the peritoneum and reduced appetite owing to continuous glucose load and sense of abdominal fullness predispose to malnutrition. 

Albumin and amino acid loss Muscle wasting Increased adipose tissue Fibrin formation in dialysate... 

Metabolic alkalosis Increased alkalinity of body fluids caused by excessive alkali (usually bicarbonate) intake or excessive acid loss (e.g., from vomiting). 

Chlorogenic acid loss is also correlated with its incorporation in browning products.3 During roasting, the diphenols, 4-ethylpyrocatechol and pyrocatechol are formed from the caffeic acid moiety and the quinic acid moiety yields phenol and benzoic acid as well as all the di- and trihydroxybenzenes.39... 

Assuming little nitric acid loss, the overall process now becomes... 

FIGURE 3 Cn hydrocarbons from dodeca-3,6,9-trienoic acid. Loss of C(l) and a single hydrogen from C(5) yield the acyclic hydrocarbon finavarrene. Decarboxylation and loss of a single hydrogen from C(8) results in (6S)-ectocarpene. No other hydrogen atoms are lost during the biosynthetic sequence. 

Most drugs act by reducing active transport rather than by enhancing it. Thus, drugs that promote uric acid loss (uricosuric agents, such as probenecid and sulfinpyrazone) probably inhibit active urate reabsorption, while pyrazinamide, which reduces urate excretion, may block the active tubular secretion of uric acid. A complicating observation is that a drug may primarily inhibit active reabsorption at one dose and active secretion at another, frequently lower, dose. For example, small amounts of salicylate will decrease total urate ex-... 

The X-substituted benzene (aniline, Figure 11.2) is activated toward electrophilic attack since the HOMO is raised significantly. The electrophile would be directed to the ortho, para, and ipso positions of the ring and to the X substituent itself. The ipso channel is usually nonproductive since the common heteroatom-based X substituents are not easily displaced as Lewis acids. Loss of substituent is frequently observed with tertiary alkyl-substituted benzenes. Attachment of the electrophile to the X substituent is most likely if... 

Another effect of high oxygen concentrations was increased oxidative attack on the solvent. This is shown in Figure 2. Methane and methyl acetate were detected in most of the runs, and it is likely that these materials were formed by free-radical attack on acetic acid. Loss of nitric acid to the nonregenerable species nitrous oxide and nitrogen was reduced in the presence of high oxygen concentrations. 

The product, if pure, will give little or no precipitate when boiled with a little dilute acetic acid. Losses incurred during recrystallization may be minimized by evaporating... 

Once again, a literature review must be done to determine which acid to use as an internal standard. The internal standard will be used to calculate the percent recovery, which quantitates organic acid losses during sample preparation. 

AJ Darragh, DJ Garrick, PJ Moughan, WH Hendriks. Correction for amino acid loss during acid hydrolysis of a purified protein. Anal Biochem 236 199-207, 1996. 

The structure of orotic acid. Loss of proton leads to orotate. Deposits of sodium orotate cause a painful condition. 

Ascorbic acid loss in acid-reduced juices never exceeded 10% except in cases where the ion-exchange resin was not completely exhausted and generally it was in the range of 3% to... 

Paper cartons with an aluminum-foil barrier between the paper and plastic are used for the distribution of some chilled products. Because of the foil barrier, products in these cartons exhibit better ascorbic acid retention than do the plastic-lined cartons. As an example, grapefruit juice stored in such cartons retained 74% of its ascorbic acid over a 40-day storage period at 4.4°C. The rate of ascorbic acid loss was 0.7% per day. Grapefruit juice in a plastic-lined container lost 1.5% of its ascorbic acid per day when stored under similar conditions. 

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