이 작품은 협업 프로젝트 BOR4STORE (부여 계약 번호 303428) 및 인프라 프로그램 H2FC (보조금 협정 제 FP7-284522)에서 유럽의 연료 전지 및 Hydruogen 공동 Undertaking에 의해 지원되었다.

1. 장치 <ol><li> 가스 공급기, 진공 시스템, 센서 (온도 및 압력), 및 (욕에 침지 될 수있는) 샘플 환경 : 고압 가스 배관으로 연결된 네 개의 주요 구성 요소로 이루어진 기본 초 임계 건조 (SCD) 장치를 사용. 건축 고품질 스테인리스 밸브, 피팅, 및 튜브 인 것을 확인, 80-300 K. 사이의 온도 범위에서 적어도 10 MPa의 압력이 정격 참고 : 회로도는 그림 1에 표시됩니다. </li><li> 질소 SCD (NSCD) 트리트먼트, 가스 공급 연구 순도는 0-10 MPa의 출구 사이의 압력 제어를위한 압력 조절기를 장착 (&gt; 99.999 %) 질소 가스가 있음을 보장한다. 장치 50 L 병 (20 MPa로)를 연결하고 사용 전에 순수한 질소를 여러 번으로 시스템을 퍼지. </li><li> 진공 시스템은 0.1Pa로 &lt;까지 진공 압력을 달성 할 수 있고, 장치에 연결되어 있는지 확인미세 제어 니들 밸브. 바람직하게는, 직렬로 배치 된 오일 프리 러핑 펌프와 분자 드래그 터보 펌프를 사용한다. </li><li> SCD 치료 동안에 압력의 정확한 측정을위한 적어도 두 개의 압력 센서를 사용하여 측정 및 진공 고압 센서 저압 센서가 0.1 내지 7 파 사이 총 측정 압력 범위를 달성했다. </li><li> 전형적인 SCD 치료를 수행하기 위해 필요한 최소한의 정확성을 위해 적어도 두 온도 센서를 사용하는 센서를 샘플 및 77-300 K 사이의 정확한 측정을위한 기본 가스 투약 폴드 내의 센서와 열 접촉 (예를 들면, K 형 열전대) . </li><li> 샘플 홀더는 처리에 필요한 시료의 양을 포함하는 적당한 내부 체적을 가지며, 스테인리스 강으로 제작되어 있는지 확인한다. 참고 : 목욕과 열 접촉에 길게 원통형 디자인 에이즈. </li><li> 샘플 용기를 닫 피팅 appropr 있는지 확인높은 압력과 반복 사용 (예를 들어,은 Swagelok VCR)에 늦는. 욕조에 샘플 홀더의 완전한 몰입을위한 튜브의 적절한 길이 (딥 튜브)를 통해 외부 환경으로부터 격리를위한 밸브 샘플 용기 볼륨을 연결합니다. </li></ol><img alt="그림 1" src="/files/ftp_upload/52817/52817fig1.jpg" /> . 욕에서 시료의 침수 후 상온 (B)에서 (A) :도 1 초 임계 건조 질소 (NSCD) 장치 전형적인 실험실에서 사용하기위한 장치의 단순화 된 NSCD 개략도. 이 연구에서 기술 된 프로세스에 대한 가스 공급을 질소이지만, 이러한 일반적인 장치는 CO 2 등의 온도와 압력의 범위 내에서 실질적 누워 임계점 다른 SCD 유체로 일반화된다. 구성 요소는 제와 일관성을 위해 표시되어 있습니다프로토콜은 여기에 설명 된 전자. <a href="https://www.jove.com/files/ftp_upload/52817/52817fig1highres.jpg" target="_blank">이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오.</a> 2. 준비 <ol><li> 샘플의 하중 0.2-0.5 g (γ-마그네슘 (BH 4) 2, 분말 형태의 습식 화학 합성 표준 건조 방법에 따라) 예컨대 아르곤 글로브 박스로서 전형적으로 불활성 분위기에서 적절한 조건하에 시료 홀더로, 아래 또는 주위 온도. 필터 가스켓 샘플 홀더 (피팅 F2)를 닫고 밸브 (밸브 V4)를 닫습니다. 장치에 샘플 홀더를 전송하고 (피팅 F1)를 연결합니다. </li><li> (V2)를 통해 진공 청소기 대피 투여 매니 폴드를 엽니 다. 열기 V3 및 피난. (V1)을 통해 질소와 장치를 제거하고 (V2)를 통해 대피. 오픈 V4는 시스템 (&lt;0.1 ​​PA)의 최소 압력에 도달하기까지 24 시간 동안 RT에서 샘플을 피난. </li><li> 샘플 목욕을 설치 (참조 <stronG&gt; 샘플 홀더 주위에 그림 2). 가위 리프트, 또는 유사한 메커니즘에 위치로 목욕을 제기하여이 작업을 수행합니다. </li><li> 110 K의 (단계 3.1 참조, T의 L) 원하는 미래 액체 온도로 히터를 설정하고 온도가 평형을 때까지 장치를 철수하는 것을 계속한다. </li></ol><img alt="그림 2" src="/files/ftp_upload/52817/52817fig2.jpg" /> 그림 2. 극저온 전기로 샘플 목욕. (왼쪽) 개략도 및 저온 유지 열 목욕 환경의 사진 (오른쪽), nscd를 처리하는 동안 샘플 홀더를 포함하는 측정 및 77-298 케이 사이의 시료 온도 제어를 허용하기위한 적절한 <a href="https://www.jove.com/files/ftp_upload/52817/52817fig2highres.jpg" target="_blank">하세요 이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오.</a> 3. 초 임계 질소 노출 <ol&gt; <li> γ - 마그네슘 (BH 4) 2, (이 프로토콜에서 시연의 주제)의 NSCD 처리를 위해이 적당한 액체 용매 밀도에 해당하는 110 케이의 액체 온도 (T의 L)을 선택 (~ 0.6 g을 ml의 -1) ; 다른 nscd를 처리 공정에이 프로토콜의 응용 프로그램에 대한 필요에 따라 조정합니다 (아래 참고 참조). </li><li> V2를 닫아 진공 시스템을 닫습니다. 압력이 상태도의 액체 영역으로 증가 할 수 있도록, 서서히 개방 V1을 스로틀 링. 2 MPa의와 T L에서 시스템을 평형. </li><li> 4 시간 동안 액체 N 2의 샘플을 만끽 해보세요. </li><li> 램프 ≤2 K 분 -1 150 (K)에 히터를 설정합니다. 압력 (이 P 최대가 MPa의 ≥10해야한다) 장치의 최대 정격 압력보다 더 이상 증가하지 않습니다 허용; 필요한 경우라면, V2를 통해 진공하는 초과 압력을 벤트. P 최대 150 K.에 시스템을 평형 </li><li> SUP의 샘플을 적시1 시간 동안 ercritical N 2. </li></ol><img alt="그림 3" src="/files/ftp_upload/52817/52817fig3.jpg" /> 도 3 질소의 위상 다이어그램. 유체 밀도 (선형 스케일에 도시) 질소의 상세한 상태도 Refprop (상태의 개질 웹은-베네딕트 - 루빈 방정식)을 사용하여 계산된다. 일정한 밀도의 41 다양 라인 나타낸다 보라색. 고상 경계와 전이 비등 라인 빨간색으로 표시되어있다. 파란색 선은 N 2를 사용하여 건조 또는 추출 처리를 위해 관련 상태도의 영역의 경계를 나타냅니다. <a href="https://www.jove.com/files/ftp_upload/52817/52817fig3highres.jpg" target="_blank">이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오.</a> 다른 물질이 프로토콜의 응용 프로그램에 대한 적절한 nscd를 처리 schem을 설정 참고 :표적 종의 효과적인 용 매화하기 위해 필요한 조건을 선택하여 E. 도 3에 도시 된 N (2)의 상태도를 참조. 액상 유체 높은 밀도를 달성하기 위해 (예를 들어, g는 0.8-1 ml의 -1), 적당한 액체 밀도 80-90 K.의 T의 L을 선택 (예를 들어, 0.6-0.8 G ml의 -1), 필요할 수 있습니다 90-115 케이 시행 착오 방식의 T는 L을 선택합니다. 4. 초 임계 질소 출시 <ol><li> 조심스럽게 V2을 스로틀 압력은 가능한 한 느리게 감소시킴으로써 진공 시스템 균열. 반복적 12-24 hr의 대략적인 시간 범위에서 고 진공 (&lt;0.1 ​​PA)에 점진적 감소를 달성하기 위해 필요에 따라 더 높은 속도로 진공 시스템 균열. </li><li> 완전히 샘플을 대피 샘플 목욕 및 완전 개방 (V2)를 제거합니다. RT 및 고진공 (&lt;0.1 ​​PA)에서 평형. </li><li> D로, 1-24 시간 동안 RT와 &lt;0.1 ​​아빠의 샘플을 드가esired. </li></ol> 5. 사후 처리 <ol><li> 닫기 밸브 V3 및 V4, 그리고 (F1 피팅) 장치로부터 샘플 홀더를 제거합니다. </li><li> 예컨대 아르곤 충진 글로브 박스와 같은 처리를 위해 불활성 환경에 샘플 홀더를 이동. 아래의 주위 온도 또​​는 밀봉 된 용기에 시료 (F2 피팅) 홀더와 상점에서 샘플을 제거합니다. </li></ol>

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저자가 공개하는 게 없다.

아마도 상대적으로 낮은 임계 온도 (126 K)로 인해, N (2)는 역사적으로 효과적인 SCD 용매로서 간과하고있다. 이전의보고에서, 3,17,42,43은 만 제외 (인해 상태도의이 영역에서의 낮은 유체 밀도 또는 단지 적당한 매화 전력을 나타내는 주변, 이상의 온도 처리의 맥락에서 언급 한 내용 매우 높은 압력 (43))에서. 초 임계 용매로서 N (2)의 실용성을 실현하는데 핵심 단계?...

건조 초 임계 유체 추출 (SFE) 및 (SCD) 방법이 아니라, 특히 식품 및 석유 산업에서, 실제 응용의 넓은 범위에서 설정뿐만 아니라, 화학 합성, 분석 및 재료 처리. 1-6 건조 사용되는 또는 임계점 위의 조건에서 추출 매체들은 더 빠르고, 깨끗하고 효율적인 전통 (액체) 기법에 비해, 높은 작동 조건의 약간의 조정에 의해 유체의 매화 전원에 대하여 동조되는 추가적인 장점을 갖는다 . 3,7 간단한 SCD 방법은 세 가지 기본 단계로 구성되어 있습니다. 첫 번째 단계는 액체에 적절하게 선택된 SCD 액에 대상 불순 화합물을 함유하는 출발 고체 (혹은 액체) 물질에 노출되어 높은 밀도가 높은 (어쩌면 선택성에 대응 (또는 거의 액체 초임)의 위상, 대상 종에 대한 7) 용매의 전원을 켭니다. 티그 두 번째 단계는 가열 유체와 용해 목표 종 분리를 초래할 수 위상 경계가 통과하지 않도록, 밀폐 용기에 선택된 SCD 유체의 임계점 위의 압축 시스템이다. 마지막 단계는 천천히 위상 경계 또는 도중에 어떠한 해로운 표면 장력 효과가 발생하지 않고, 다시 탈출 대상 종을 포함하는 액체 용액을 허용 임계 온도 이상의 온도에서 진공 SCD 유체의 압력을 감압한다. 출발 물질은 표적 종 고갈 채로 필요하다면 반복 치료를 실시 할 수있다. 초 임계 유체 추출의 경우, 대상 용질 종 목적 생성물이고, 다른 경우에는 더욱 사용하기위한 용액으로부터. -8,9- 수집, 건조 또는 정제 된 출발 물질이 목적 생성물이며, 추출 된 불순물은 폐기된다. 후자의 시나리오, 본 명세서SCD 접근으로서, 높은 표면적, 진공 하에서 기존의 열처리 방법은 많은 경우에 기공을 비운에 충분하지 않은 유기 금속 틀 (MOFs와) 같은 미세 다공성 물질의 전처리에 대한 효율적인 전략으로 밝혀졌다 모든 원치 않는 손님, 또는 기공 붕괴 초래한다. (10) 이산화탄소 SCD (CSCD) 처리는 지금까지 1,000 %에 치료 물질을 통해 질소가 접촉 할 수있는 표면 영역의 증가로 이어지는으로 MOFs, 11 일과 후 합성 과정 12 이러한 촉매 활성 등의 개선. (13) 다른 주목할만한 초 임계 유체 응용 화학 반응을위한 광범위하게 조정할 수있는 매체로하고, 14 ~ 16 초 임계 유체 크로마토 그래피 (SCFC) 6,17,18 및 에어로젤과 첨단 복합 재료의 합성. 19- (22) 애플리케이션을 건조, SCD 유체는 두 가지 기준을 기반으로 선택된다 : a) 동작의 근접성중요한 포인트는 (편의를 위해 에너지 비용이나 공정의 복잡성 감소시키는)을 주위 조건하는 표적 종에 대해서와 b)의 용 매화 전원. 이산화탄소 (CO 2)가, 비 독성, 불연성 및 저렴한 때문에 많은 응용에서 편리한 SCD 유체 입증하고 있으며, 그 근처에 액체 일반적인 유기 표적 종의 수를 향해 높은 용 매화 능력을 나타내도록 조정될 수있다 . 1-3,7-9 다른 일반적인 초 임계 용매 (또는 공용 매) (&lt;10 MPa로 압력과 273-323 K의 온도에서) 상태는 물 (그 주위 온도 및 초 임계 상태 사이의 용매 특성의 놀라운 범위에 걸쳐 포함 극성 (양성 자성 및 비 양성 자성) 비극성에 및 주변 조건에 비교적 가까운 임계점을 갖는로부터 스펙트럼을 커버 (23)), 아세톤, 에틸렌, 메탄올, 에탄올, 및 에탄. 이산화탄소가 사용될까지 가장 흔한 SCD 유체가있다. CSCD 확립 방법에있어서, 반응성출발 물질이없는 방청 인자의 CO 2 임계점 부근의 온도에서 매우 약하게 반응성 때문이다. 그러나, 가열 하에서 그들의 (아마도 의도적 맞춤) 불안정성에 부가 물 또는 이산화탄소의 존재 하에서 강한 반응성 소위 복합 하이드 라이드 (예를 들어, 알라 네이트 및 보로 하이드 라이드) 처리에서 본 독특한 도전 재료로서 특정 부류 . 24-26은 또한 나노 구조 및 / 또는 다공성 31-33 품종에 따라서도 큰 국제 고밀도 수소 저장 화합물, 27-30 등의 재료에 대한 관심이있다. 반응성, 불안정 및 나노 물질의 효율적인 정제를 위해, SCD 방법은 좁은 공동으로 침투에 적합한 작은 분자 직경을 가지고 있으며, 또한 향해 높은 용 매화 능력을 갖는다. 34 SCD 유체가 사용되어야 유망한 전략 아르 타겟 불순물 WHI르는 출발 물질 자체 향해 반응성 나머지. 여기서, 예컨대 추출, 특히 건조 애플리케이션 효과적인 초 임계 유체로서 질소를 사용하는 (N 2)가 제공된다. 특정 초 임계 질소 건조 (NSCD) 방법론은 목표 종 디보 란 및 N 부틸 화합물 (비슷하지만 N 개의 뷰 테인 구체적으로 식별되지 않음)를 모두 포함 γ 상 마그네슘 보로 하이드 라이드의 정제에 대하여 설명한다. 다음 프로토콜은 쉽게 다른 초 임계 질소 건조 또는 추출 과정에 일반 연장을 수정할 수 있습니다.

<table><tbody><tr><td>Compressed Nitrogen Gas</td><td>Messer Schweiz AG</td><td></td><td>50 L bottle, purity &gt; 99.999%, &amp;lt;3 ppmv H&lt;sub&gt;2&lt;/sub&gt;O</td></tr><tr><td>Liquid Nitrogen</td><td>Pan Gas AG</td><td></td><td>Bulk storage, on site</td></tr><tr><td>Custom Supercritical Drying Apparatus</td><td>Empa</td><td></td><td>Swagelok (compression fitting and VCR) components</td></tr><tr><td>Custom Cryogenic Furnace Bath</td><td>Empa</td><td></td><td></td></tr><tr><td>Custom Labview Interface</td><td>Empa</td><td></td><td></td></tr></tbody></table>

supercritical nitrogen processing for the purification of reactive porous materials

Supercritical fluid extraction and drying methods are well established in numerous applications for the synthesis and processing of porous materials. Herein, nitrogen is presented as a novel supercritical drying fluid for specialized applications such as in the processing of reactive porous materials, where carbon dioxide and other fluids are not appropriate due to their higher chemical reactivity. Nitrogen exhibits similar physical properties in the near-critical region of its phase diagram as compared to carbon dioxide: a widely tunable density up to ~1 g ml-1, modest critical pressure (3.4 MPa), and small molecular diameter of ~3.6 &#197;. The key to achieving a high solvation power of nitrogen is to apply a processing temperature in the range of 80-150 K, where the density of nitrogen is an order of magnitude higher than at similar pressures near ambient temperature. The detailed solvation properties of nitrogen, and especially its selectivity, across a wide range of common target species of extraction still require further investigation. Herein we describe a protocol for the supercritical nitrogen processing of porous magnesium borohydride.

알칼리 및 알칼리 토 금속 보로 하이드 라이드가 디보 란은 또한 때때로 탈리 가스에서 검출 된 같은 분해. 27, 29 다른 분해 생성물에 기체 수소의 큰 콘텐츠를 제공 가능한 수소 저장 물질이지만, 그 기원은 명확 선험적 아니다 ; 그들이 순수한 위상 분해 제품이지만, 또한 남은 화학 합성에서 불순물의 반응의 불순물 및 제품 일 수있다. (35), 마그네슘 보로 하이드 라이드 다공질 ?...

Watch this Scientific Journal Video about Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials at JoVE.com

Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials

질소 인해 작은 분자 크기, 거의 액체, 초 임계 영역에서 고 밀도 및 화학적 불활성으로 추출 또는 건조 공정을위한 유효 임계 유체이다. 우리는 반응성, 다공성 물질의 정제 처리를 위해 초 임계 건조 질소 프로토콜을 제시한다.

반응성이 있음 다공성 물질의 정제를위한 초 임계 질소 처리

Supercritical fluid extraction and drying methods are well established in numerous applications for the synthesis and processing of porous materials. ...

supercritical-nitrogen-processing-for-purification-reactive-porous

Research

JoVE Journal

Chemistry

14.7K 조회수.  Empa, Swiss Federal Laboratories for Materials Science and Technology.  질소 인해 작은 분자 크기, 거의 액체, 초 임계 영역에서 고 밀도 및 화학적 불활성으로 추출 또는 건조 공정을위한 유효 임계 유체이다. 우리는 반응성, 다공성 물질의 정제 처리를 위해 초 임계 건조 질소 프로토콜을 제시한다. 

비디오: Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials

Preparing Silica Aerogel Monoliths via a Rapid Supercritical Extraction Method

A procedure for the fabrication of monolithic silica aerogels in eight hours or less via a rapid supercritical extraction process is described. The procedure requires 15-20 min of preparation time, during which a liquid precursor mixture is prepared and poured into wells of a metal mold that is placed between the platens of a hydraulic hot press, followed by several hours of processing within the hot press. The precursor solution consists of a 1.0:12.0:3.6:3.5 x 10-3 molar ratio of tetramethylorthosilicate (TMOS):methanol:water:ammonia. In each well of the mold, a porous silica sol-gel matrix forms. As the temperature of the mold and its contents is increased, the pressure within the mold rises. After the temperature/pressure conditions surpass the supercritical point for the solvent within the pores of the matrix (in this case, a methanol/water mixture), the supercritical fluid is released, and monolithic aerogel remains within the wells of the mold. With the mold used in this procedure, cylindrical monoliths of 2.2 cm diameter and 1.9 cm height are produced. Aerogels formed by this rapid method have comparable properties (low bulk and skeletal density, high surface area, mesoporous morphology) to those prepared by other methods that involve either additional reaction steps or solvent extractions (lengthier processes that generate more chemical waste).The rapid supercritical extraction method can also be applied to the fabrication of aerogels based on other precursor recipes.

This article describes a rapid supercritical extraction method for fabricating silica aerogels. By utilizing a confined mold and hydraulic hot press, monolithic aerogels can be made in eight hours or less.

빠른 초 임계 추출 방법을 통해 실리카 에어로젤, 모노 리드 (monolith)를 준비

A procedure for the fabrication of monolithic silica aerogels in eight hours or less via a rapid supercritical extraction process is described. The ...

연구

화학

Preparation of Highly Porous Coordination Polymer Coatings on Macroporous Polymer Monoliths for Enhanced Enrichment of Phosphopeptides

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous polymer monoliths. The developed approach is based on the preparation of a macroporous polymer containing carboxylic acid functional groups and the subsequent step-by-step solution-based controlled growth of a layer of a porous coordination polymer on the surface of the pores of the polymer monolith. The prepared metal-organic polymer hybrid has a high specific micropore surface area. The amount of iron(III) sites is enhanced through metal-organic coordination on the surface of the pores of the functional polymer support. The increase of metal sites is related to the number of iterations of the coating process.
The developed preparation scheme is easily adapted to a capillary column format. The functional porous polymer is prepared as a self-contained single-block porous monolith within the capillary, yielding a flow-through separation device with excellent flow permeability and modest back-pressure. The metal-organic polymer hybrid column showed excellent performance for the enrichment of phosphopeptides from digested proteins and their subsequent detection using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The presented experimental protocol is highly versatile, and can be easily implemented to different organic polymer supports and coatings with a plethora of porous coordination polymers and metal-organic frameworks for multiple purification and/or separation applications.

A procedure for the preparation of porous hybrid separation media composed of a macroporous polymer monolith internally coated by a high surface area microporous coordination polymer is presented.

포스 포의 향상된 농축을위한 거대 다공성 고분자 모노리스에 다공성 조정 폴리머 코팅의 제조

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous ...

Procedures of Laboratory Fumigation for Pest Control with Nitric Oxide Gas

Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. This paper provides detailed protocols for conducting NO fumigation on fresh products and procedures for residue analysis and product quality evaluation. An airtight fumigation chamber containing fresh fruit and vegetables is first flushed with nitrogen (N2) to establish an ultralow oxygen (ULO) environment followed by injection of NO. The fumigation chamber is then kept at a low temperature of 2 - 5 &#176;C for a specified time period necessary to kill a target pest to complete a fumigation treatment. At the end of a fumigation treatment, the fumigation chamber is flushed with N2 to dilute NO prior to opening the chamber to ambient air to prevent the reaction between NO and O2, which produces NO2 and may damage delicate fresh products. At different times after NO fumigation, NO2 in headspace and nitrate and nitrite in liquid samples were measured as residues. Product quality was evaluated after 2 weeks of post-treatment cold storage to determine effects of NO fumigation on product quality. Keeping&#160;O2 from reacting with NO is critical to NO fumigation and is an important part of the protocols. Measuring NO levels is challenging and a practical solution is provided. Possible protocol modifications are also suggested for measuring NO levels in the fumigation chambers as well as residues. NO fumigation has the potential to be a practical alternative to methyl bromide fumigation for postharvest pest control on fresh and stored products. This publication is intended to assist other researchers in conducting NO fumigation research for postharvest pest control and accelerating the development of NO fumigation for practical applications.

This paper describes nitric oxide (NO) fumigation protocols for postharvest pest control. Fumigation chambers are flushed with nitrogen (N2) to establish ultralow oxygen conditions before NO is injected. At the end, chambers are flushed with N2 to dilute NO before exposing products to ambient air to prevent exposure to NO2.

산화 질소 가스와 해충에 대 한 훈 증 실험실의 절차

Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. This paper provides detailed protocols for conducting NO fumigation on ...

환경과학

On-line Analysis of Nitrogen Containing Compounds in Complex Hydrocarbon Matrixes

The shift to heavy crude oils and the use of alternative fossil resources such as shale oil are a challenge for the petrochemical industry. The composition of heavy crude oils and shale oils varies substantially depending on the origin of the mixture. In particular they contain an increased amount of nitrogen containing compounds compared to the conventionally used sweet crude oils. As nitrogen compounds have an influence on the operation of thermal processes occurring in coker units and steam crackers, and as some species are considered as environmentally hazardous, a detailed analysis of the reactions involving nitrogen containing compounds under pyrolysis conditions provides valuable information. Therefore a novel method has been developed and validated with a feedstock containing a high nitrogen content, i.e., a shale oil. First, the feed was characterized offline by comprehensive two-dimensional gas chromatography (GC &#215; GC) coupled with a nitrogen chemiluminescence detector (NCD). In a second step the on-line analysis method was developed and tested on a steam cracking pilot plant by feeding pyridine dissolved in heptane. The former being a representative compound for one of the most abundant classes of compounds present in shale oil. The composition of the reactor effluent was determined via an in-house developed automated sampling system followed by immediate injection of the sample on a GC &#215; GC coupled with a time-of-flight mass spectrometer (TOF-MS), flame ionization detector (FID) and NCD. A novel method for quantitative analysis of nitrogen containing compounds using NCD and 2-chloropyridine as an internal standard has been developed and demonstrated.

A method combining comprehensive two-dimensional gas chromatography with nitrogen chemiluminescence detection has been developed and applied to on-line analysis of nitrogen containing compounds in a complex hydrocarbon matrix.

복잡한 탄화수소 행렬에 질소 함유 화합물의 온라인 분석

The shift to heavy crude oils and the use of alternative fossil resources such as shale oil are a challenge for the petrochemical industry. The ...

Preparation of Biomass-based Mesoporous Carbon with Higher Nitrogen-/Oxygen-chelating Adsorption for Cu(II) Through Microwave Pre-Pyrolysis

An environment-friendly technique for synthesizing biomass-based mesoporous activated carbon with high nitrogen-/oxygen-chelating adsorption for Cu(II) is proposed. Bagasse impregnated with phosphoric acid is utilized as the precursor. To pyrolyze the precursor, two separate heating modes are used: microwave pyrolysis and conventional electric-heating pyrolysis. The resulting bagasse-derived carbon samples are modified with nitrification and reduction modification. Nitrogen (N)/oxygen (O) functional groups are simultaneously introduced to the surface of activated carbon, enhancing its adsorption of Cu(II) by complexing and ion-exchange. Characterization and copper adsorption experiments are performed to investigate the physicochemical properties of four prepared carbon samples and determine which heating method favors the subsequent modification for doping of N/O functional groups. In this technique, based on analyzing data of nitrogen adsorption, Fourier transform infrared spectroscopy, and batch adsorption experiments, it is proven that microwave-pyrolyzed carbon has more defect sites and, therefore, time-saving effective microwave pyrolysis contributes more N/O species to the carbon, although it leads to a lower specific surface area. This technique offers a promising route to synthesis adsorbents with higher nitrogen and oxygen content and a higher adsorption capacity of heavy-metal ions in wastewater remediation applications.

Preparation of Biomass-based Mesoporous Carbon with Higher Nitrogen-/Oxygen-chelating Adsorption for CuII Through Microwave Pre-Pyrolysis

Here, we present a protocol to synthesize nitrogen/oxygen dual-doped mesoporous carbon from biomass by chemical activation in different pyrolysis modes followed by modification. We demonstrate that the microwave pyrolysis benefits the subsequent modification process to simultaneously introduce more nitrogen and oxygen functional groups on the carbon.

바이오 매스 기반 Mesoporous 탄소 높은 질소-의 준비 / 전자 사전 열 분해를 통해 Cu(II)에 대 한 흡착 산소 킬레이트 화

An environment-friendly technique for synthesizing biomass-based mesoporous activated carbon with high nitrogen-/oxygen-chelating adsorption for Cu(II) is ...

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O

The importance of understanding the fate of nitrate (NO3&#8722;), which is the dominant N species transferred from terrestrial to aquatic ecosystems, has been increasing because global nitrogen loads have dramatically increased following industrialization. Dissimilatory nitrate reduction to ammonium (DNRA) and denitrification are both microbial processes that use NO3&#8722; for respiration. Compared to denitrification, quantitative determinations of the DNRA activity have been carried out only to a limited extent. This has led to an insufficient understanding of the importance of DNRA in NO3&#8722; transformations and the regulating factors of this process. The objective of this paper is to provide a detailed procedure for the measurement of the potential DNRA rate in environmental samples. In brief, the potential DNRA rate can be calculated from the 15N-labeled ammonium (15NH4+) accumulation rate in 15NO3&#8722; added incubation. The determination of the 14NH4+ and 15NH4+ concentrations described in this paper is comprised of the following steps. First, the NH4+ in the sample is extracted and trapped on an acidified glass filter as ammonium salt. Second, the trapped ammonium is eluted and oxidized to NO3&#8722; via persulfate oxidation. Third, the NO3&#8722; is converted to N2O via an N2O reductase deficient denitrifier. Finally, the converted N2O is analyzed using a previously developed quadrupole gas chromatography&#8211;mass spectrometry system. We applied this method to salt marsh sediments and calculated their potential DNRA rates, demonstrating that the proposed procedures allow a simple and more rapid determination compared to previously described methods.

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O

A series of methods to determine the potential DNRA rate based on 14NH4+/15NH4+ analyses is provided in detail. NH4+ is converted into N2O via several steps and analyzed using quadrupole gas chromatography&#8211;mass spectrometry.

14NH4+/15NH4+ N2O로순차적변환을 통한 분석 에 따른 암모늄에 대한 질산염 감소의 잠재적 비율 측정

The importance of understanding the fate of nitrate (NO3&#8722;), which is the dominant N species transferred from terrestrial to aquatic ecosystems, has ...

Surface Properties of Synthesized Nanoporous Carbon and Silica Matrices

In this work, we report the synthesis and characterization of ordered nanoporous carbon material (also called ordered mesoporous carbon material [OMC]) with a 4.6 nm pore size, and ordered silica porous matrix, SBA-15, with a 5.3 nm pore size. This work describes the surface properties of nanoporous molecular sieves, their wettability, and the melting behavior of D2O confined in the differently ordered porous materials with similar pore sizes. For this purpose, OMC and SBA-15 with highly ordered nanoporous structures are synthesized via impregnation of the silica matrix by applying a carbon precursor and by the sol-gel method, respectively. The porous structure of investigated systems is characterized by an N2 adsorption-desorption analysis at 77 K. To determine the electrochemical character of the surface of synthesized materials, potentiometric titration measurements are conducted; the obtained results for OMC shows a significant pHpzc shift toward the higher values of pH, relative to SBA-15. This suggests that investigated OMC has surface properties related to oxygen-based functional groups. To describe the surface properties of the materials, the contact angles of liquids penetrating the studied porous beds are also determined. The capillary rise method has confirmed the increased wettability of the silica walls relative to the carbon walls and an influence of the pore roughness on the fluid/wall interactions, which is much more pronounced for silica than for carbon mesopores. We have also studied the melting behavior of D2O confined in OMC and SBA-15 by applying the dielectric method. The results show that the depression of the melting temperature of D2O in the pores of OMC is about 15 K higher relative to the depression of the melting temperature in SBA-15 pores with a comparable 5 nm size. This is caused by the influence of adsorbate/adsorbent interactions of the studied matrices.

Here we report the synthesis and characterization of ordered nanoporous carbon (with a 4.6 nm pore size) and SBA-15 (with a 5.3 nm pore size). The work describes the surface and textural properties of nanoporous molecular sieves, their wettability, and the melting behavior of D2O confined in the materials.

합성된 성공 탄소 그리고 실리 카 매트릭스의 표면 특성

In this work, we report the synthesis and characterization of ordered nanoporous carbon material (also called ordered mesoporous carbon material [OMC]) ...

High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy

Nuclear magnetic resonance (NMR) spectroscopy represents an important technique to understand the structure and bonding environments of molecules. There exists a drive to characterize materials under conditions relevant to the chemical process of interest. To address this, in situ high-temperature, high-pressure MAS NMR methods have been developed to enable the observation of chemical interactions over a range of pressures (vacuum to several hundred bar) and temperatures (well below 0 &#176;C to 250 &#176;C). Further, the chemical identity of the samples can be comprised of solids, liquids, and gases or mixtures of the three. The method incorporates all-zirconia NMR rotors (sample holder for MAS NMR) which can be sealed using a threaded cap to compress an O-ring. This rotor exhibits great chemical resistance, temperature compatibility, low NMR background, and can withstand high pressures. These combined factors enable it to be utilized in a wide range of system combinations, which in turn permit its use in diverse fields as carbon sequestration, catalysis, material science, geochemistry, and biology. The flexibility of this technique makes it an attractive option for scientists from numerous disciplines.

The molecular structures and dynamics of solids, liquids, gases, and mixtures are of critical interest to diverse scientific fields. High-temperature, high-pressure in situ MAS NMR enables detection of the chemical environment of constituents in mixed phase systems under tightly controlled chemical environments.

Nuclear magnetic resonance (NMR) spectroscopy represents an important technique to understand the structure and bonding environments of molecules. There ...

Ammonia Synthesis at Low Pressure

Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in areas requiring ammonia for synthetic fertilizer. Such wind energy is often called &#34;stranded,&#34; because it is only available far from population centers where it can be directly used.
In the proposed low pressure process, nitrogen is made from air using pressure swing absorption, and hydrogen is produced by electrolysis of water. While these gases can react at approximately 400 &#176;C in the presence of a promoted conventional catalyst, the conversion is often limited by the reverse reaction, which makes this reaction only feasible at high pressures. This limitation can be removed by absorption on an ammine-like calcium or magnesium chloride. Such alkaline metal halides can effectively remove ammonia, thus suppressing the equilibrium constraints of the reaction. In the proposed absorption-enhanced ammonia synthesis process, the rate of reaction may then be controlled not by the chemical kinetics nor the absorption rates, but by the rate of the recycle of unreacted gases. The results compare favorably with ammonia made from a conventional small scale Haber-Bosch process.

Ammonia can be synthesized at low pressure by using a conventional catalyst and an ammonia selective absorbent.

저압에서 암모니아 합성

Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in ...

생체공학

Versatile Home-Built Microwave-Assisted System for Peptide Synthesis

An Inexpensive Adaptation of a Commercial Microwave Reactor for Solid Phase Peptide Synthesis

A home-built apparatus to perform solid phase peptide synthesis (SPPS), assisted by microwave irradiation and heating, is presented. In contrast to conventional SPPS reaction vessels, which drain solvent and byproducts via a frit located at the bottom of the vessel, the presented apparatus employs a gas dispersion tube under vacuum to remove solvent, byproducts, and excess reagents. The same gas dispersion tube supplies nitrogen gas agitation of the SPPS beads during the reaction steps of coupling and deprotection. Microwave heating is beneficial for SPPS couplings of sterically hindered residues, such as alpha-aminoisobutyric acid (Aib), an alpha,alpha-dialkylated amino acid residue. This home-built apparatus has been used to prepare, via manual Fmoc SPPS methods, heptameric and octameric peptides dominated by the Aib residue, which is notoriously difficult to couple under standard room temperature conditions and reagents. Further, typical commercial microwave SPPS reactors are dedicated exclusively to SPPS synthesis rendering them inaccessible to non-SPPS users. In contrast, the presented apparatus preserves the versatility of the microwave reactor for conventional microwave acceleration of chemical reactions, as the apparatus is trivially removed from the commercial microwave reactor.

A simple, inexpensive, and novel apparatus for performing solid phase peptide syntheses in a commercial microwave reactor is presented.

A home-built apparatus to perform solid phase peptide synthesis (SPPS), assisted by microwave irradiation and heating, is presented. In contrast to ...