Corrosion inhibition of α,β-unsaturated carbonyl compounds on steel in acid medium

Corrosion inhibition of three α,β-unsaturated carbonyl compounds on N80 steel at high temperature and in concentrated acid medium was evaluated, and the inhibition mechanism was investigated. The results proved that both cinnamaldehyde and benzalacetone had an evident anticorrosion effect and could reduce the corrosion of steel effectively in acid medium, α,β-unsaturated carbonyl compounds with a benzene ring structure had good adsorption on steel surface. The experiments proved that polymerization of α,β-unsaturated carbonyl compounds on the steel surface at a high temperature and in concentrated acid medium resulted in a good corrosion inhibiting effect, which was attributed to the structures of α,β-unsaturated carbonyl compounds.

MICHAEL ADDITION OF NITROALKANE TO α,β-UNSATURATED CARBONYL COMPOUNDS ON KF / Al_2O_3/ PEG4000

Michael addition of nitroalkanes to α,β-unsaturated carbonyl compounds occurs in the presence of KF/AI_2O_3/PEG4000 without solvent.Yields are fair to good and work-ups are easy.

Trifluoromethylation of Carbonyl Compounds with Sodium Trifluoroacetate

In the presence of copper （I） halide as catalyst, a variety of carbonyl compounds could be trifluoromethylated with sodium trifluoroacetate to give the corresponding alcohols in moderate to high yields.

[Hmim]_3PW_(12)O_(40):A high-efficient and green catalyst for the acetalization of carbonyl compounds

[Hmim]_3PW_(12)O_(40) was developed and used in the acetalization of carbonyl compounds in excellent yields.The ionic liquidheteropoly acid hybrid compound and reaction medium formed temperature-dependent phase-separation system with the ease of product as well as catalyst separation.The catalyst was recycled more than 10 times without any apparent loss of catalytic activity.

Zeolite-Catalyzed Acetalization Ⅰ. Synthesis of Some Acetals and Ketals through Reaction of Carbonyl Compounds with Ethanediol

The acetalization of a series of carbonyl compounds with ethanediolwas performed over two self-steaxned HY zeolle catalpsts' The acetal and ketaiproducts were obtained with high ytelds Espectw, the HY zeollte with highfraxnework Si/A1 ratio was proven to be suitable cataipst for the acetabotion ofunsaturated carbonyl compounds, during which the C =C double bond was notperturbed

A New HPLC Method to Determine Carbonyl Compounds in Air

In this paper, a new HPLC method was established to determine the carbonyl compounds in air. As the absorbent, 2, 4-dinitrophenylhydrazine (2, 4-DNPH) reacted with carbonyls specifically, which form the corresponding 2,4-dinitrophenylhydrazones, then analyzed by HPLC. The chromatographic conditions, the recovery rate, stability of samples, reagent blank, sampling efficiency were all studied systematically. The results showed that this established method had high sensitivity and good selectivity compared with other analytical methods, and it can determine ten carbonyl compounds in air in 26 min simultaneously.

OXIDATION OF α-METHYL OR α-METHYLENE GROUPS IN CARBONYL COMPOUNDS WITH AMMONIUM CHLOROCHROMATE

This paper reports a new method for oxidizing the α-methyl or α-methylene groups in carbonyl compounds into 1,2-dicarbonyl compounds by ammonium chlorochromate(ACC).

Addition of Per(poly)fluoroalkyl Iodides to vinyl Cyclopropane Derivatives: Synthesis of Fluoroalkyl Substituted γ,δ-Unsaturated Carbonyl Compounds

In the presence of CrC13 /Fe bimetal couple,per(poly)fluoroalkyl iodides add to vinyl cyclopropane compounds giving addition-ring-opening products in good yields.

CONVERSION OF ACETALS AND KETALS TO CARBONYL COMPOUNDS PROMOTED BY ZrCl_4-NaBH_4

In our study on the chemistry of ZrCl_4-NaBH_4,we have found that aldehydes and ketones can be regenerated from acetals and ketals at 30℃ in Et_2O in high yield The reaction mechanism was discussed.

α-C(sp^(3))-H Arylation of Cyclic Carbonyl Compounds

α-C(sp^(3))-H arylation is an important type of C-H functionalization.Various biologically significant natural products,chemi-cal intermediates,and drugs have been effectively prepared via C-H functionalization.Cyclic carbonyl compounds comprise of cyclic ketones,enones,lactones,and lactams.Theα-C(sp^(3))-H arylation of these compounds have been exhibited high efficiency in forming C(sp^(3))-C(sp^(2))bonds,played a crucial role in organic synthesis,and attracted majority of interests from organic and medicinal communities.This review focused on the most significant advances including methods,mechanism,and applications in total synthesis of natural products in the field ofα-C(sp^(3))-H arylations of cyclic carbonyl compounds in recent years.

Selectivity of Organosamarium(Ⅲ) Hydride in Reducing Unsaturated Carbonyl Compounds

The selectivity of organosamarium(Ⅲ) hydride in reducing unsaturated carbonyl compounds has been studied. Dimeric organosamarium hydride[(C_9H_7)_2SmH]_2·4THF·NaCl prepared by the reaction of (C_9H_7)_2SmCl·2THF with NaH in THF reacts with unsaturated carbonyl compounds to give the corresponding reduction products with a high selectivity. The carbonyl groups have been reduced while the carbon-carbon double bonds are not affected.

Emissions of volatile organic compounds and carbonyl compounds from residential coal combustion in China

Emissions of volatile organic compounds （VOCs） and carbonyls from residential coal combustion of five coals with different maturities were studied in a simulated room.The coals were burned in form of honeycomb briquettes in a domestic coal stove,one of the most common fuel/stove combinations in China.Through a dilution system,VOCs and carbonyls samples were collected by canisters and silica-gel cartridges and analyzed by gas chromatography and mass spectrum （GC/MS） and high performance liquid chromatography/ultraviolet （HPLC/UV）,respectively.The results show that the bituminous coals with medium volatile matter content produce the highest emissions while the anthracite yields the lowest.Among the identified carbonyls from the coal smoke,the aromatic compounds （benzaldehyde,2,5-dimethylbenzaldehyde and p-tolualdehyde,m/o-tolualdehyde,benzene,m,p-xylene and trimethyl-benzene） were relatively abundant,which might be due to the molecular structure of the coal.For formaldehyde,aromatic carbonyls and aliphatic alkanes,their concentrations increase up to the maximum values and then decrease with increasing coal maturity.The total carbonyls and VOCs have the same tendency,which was observed for the emission factors of organic carbon （OC）,elemental carbon （EC）,particulate matter （PM） and polycyclic aromatic hydrocarbons （PAHs） detected in the series study.

Silica sulfuric acid:A versatile reagent for oxathioacetalyzation of carbonyl compounds and deprotection of 1,3-oxathiolanes

有获得的 1,3-oxathiolanes 的 2-mercaptoethanol 和 deprotection 的羰基混合物的 Oxathioacetalyzation 容易面对硅石被执行硫磺的酸(SSA ) 。所有反应在温和、完全异构的反应条件下面被执行在对高收益好。

Asymmetric Reductive Amination of Carbonyl Compounds by Using<i>N,N,N</i>-Tributylpropanaminium Based Novel Chiral Ionic Liquid

Asymmetric reductive amination of carbonyl compounds was carried out using a novel class of aliphatic quarternary ammonium based chiral ionic liquid. S-(+)-2,3-dihydroxy-N,N,N-tributylpropanaminum bromide chiral ionic liquid has been synthesized, characterized and used for asymmetric reductive amination of carbonyl compounds in the presence of sodium borohydride. These preliminary results are encouraging and advocate dual role of novel ionic liquid as a medium and reducing agent for proficient conversion of ketones to amines, however, reductive amination reaction needs to be established for other substituents.

I₂/Nanostructured Pyrophosphate : A Mild and Efficient Catalyst for the Selective Protection of Carbonyl Compounds

A new solvent free method for protection of carbonyl compounds as their thioacetals has been accomplished through the use of iodine supported on nanostructured pyrophosphate. Advantages of the methodology include very short reaction time, the requirement for minimum amounts of catalyst, the remarkably simple experimental procedure, and no necessity for solvents or inert atmospheres, excellent yields and recyclability of the catalyst used. An efficient method for the chemoselective thioacetalization of ketones in the presence of aldehydes using I2/nanostructured pyrophosphate is also reported in this article. The nanostructured pyrophosphate was characterized by scanning electron microscopy, X-ray diffraction, infrared spectroscopy, Transmission electron microscopy and thermal gravimetric analysis, respectively.

Real-world emission characteristics of carbonyl compounds from agricultural machines based on a portable emission measurement system

Emissions of carbonyl compounds from agricultural machines cannot be ignored.Carbonyl compounds can cause the formation of ozone(O3)and secondary organic aerosols,which can cause photochemical smog to form.In this study,20 agricultural machines were tested using portable emission measurement system(PEMS)under real-world tillage processes.The exhaust gases were sampled using 2,4-dinitrophenylhydrazine cartridges,and 15 carbonyl compounds were analyzed by high-performance liquid chromatography.Carbonyl compound emission factors for agricultural machines were 51.14–3315.62 mg/(kg-fuel),and were 2.58±2.05,0.86±1.07 and 0.29±0.20 g/(kg-fuel)for China 0,China II and China III emission standards,respectively.Carbonyl compound emission factor for sowing seeds of China 0 agricultural machines was 3.32±1.73 g/(kg-fuel).Formaldehyde,acetaldehyde and acrolein were the dominant carbonyl compounds emitted.Differences in emission standards and tillage processes impact ozone formation potential(OFP).The mean OFP was 20.15±16.15 g O3/(kg-fuel)for the China 0 emission standard.The OFP values decreased by 66.9% from China 0 to China II,and 67.4%from China II to China III.The mean OFP for sowing seeds of China 0 agricultural machines was 25.92±13.84 g O3/(kg-fuel).Between 1.75 and 24.22 times more ozone was found to be formed during sowing seeds than during other processes for China 0 and China II agricultural machines.Total carbonyl compound emissions from agricultural machines in China was 19.23 Gg in 2019.The results improve our understanding of carbonyl compound emissions from agricultural machines in China.

Investigation of carbonyl compound sources at a rural site in the Yangtze River Delta region of China

Carbonyl compounds are important intermediates in atmospheric photochemistry, but their primary sources are still not understood well. In this work, carbonyls, hydrocarbons,and alkyl nitrates were continuously measured during November 2011 at a rural site in the Yangtze River Delta region of China. Mixing ratios of carbonyls and hydrocarbons showed large fluctuations during the entire measurement. The average level for total measured volatile organic compounds during the pollution episode from 25 th to 27 th November, 2011 was 91.6 ppb, about 7 times the value for the clean period of 7th–8th, November, 2011. To preliminarily identify toluene sources at this site, the emission ratio of toluene to benzene（T/B） during the pollution episode was determined based on photochemical ages derived from the relationship of alkyl nitrates to their parent alkanes. The calculated T/B was5.8 ppb/ppb, significantly higher than the values of 0.2–1.7 ppb/ppb for vehicular exhaust and other combustion sources, indicating the dominant influence of industrial emissions on ambient toluene. The contributions of industrial sources to ambient carbonyls were then calculated using a multiple linear regression fit model that used toluene and alkyl nitrates as respective tracers for industrial emission and secondary production. During the pollution episode, 18.5%, 69.0%, and 52.9% of measured formaldehyde, acetaldehyde, and acetone were considered to be attributable to industrial emissions. The emission ratios relative to toluene for formaldehyde, acetaldehyde, and acetone were determined to be 0.10, 0.20 and0.40 ppb/ppb, respectively. More research on industrial carbonyl emission characteristics is needed to understand carbonyl sources better.

PEG-OSO_3H as an efficient and recyclable catalyst for the synthesis of β-amino carbonyl compounds via the Mannich reaction in PEG-H_2O

Sulfuric acid-modified polyethylene glycol 6000（PEG-OSO_3H） was applied as an efficient and recyclable catalyst for the synthesis ofβ-amino carbonyl compounds via the Mannich reaction between aldehydes,aromatic ketones and aromatic amines at room temperature using PEG400-H_2O（1：1） as environment-friendly solvents.The reactions were completed in short times and mild reaction conditions with good to excellent yields.